Installation, Operation and Maintenance Manual

Transcription

1 Part # Energy Recovery Ventilators Installation, Operation and Maintenance Manual Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the product described. Protect yourself and others by observing all safety information. Failure to comply with instructions could result in personal injury and/or property damage! Retain instructions for future reference. Model RT General Safety Information Only qualified personnel should install this system. Personnel should have a clear understanding of these instructions and should be aware of general safety precautions. Improper installation can result in electric shock, possible injury due to coming in contact with moving parts, as well as other potential hazards, including environmental. Other considerations may be required if high winds or seismic activity are present. If more information is needed, contact a licensed professional engineer before moving forward. 1. Follow all local electrical and safety codes, as well as the National Electrical Code (NEC), the National Fire Protection Agency (NFPA), where applicable. Follow the Canadian Electric Code (CEC) in Canada. 2. All moving parts must be free to rotate without striking or rubbing any stationary objects. 3. Unit must be securely and adequately grounded. 4. Do not spin fan wheel faster than maximum cataloged fan RPM. Adjustments to fan speed significantly effects motor load. If the fan RPM is changed, the motor current should be checked to make sure it is not exceeding the motor nameplate amps. 5. Do not allow the power cable to kink or come in contact with oil, grease, hot surfaces or chemicals. Replace cord immediately if damaged. 6. Verify that the power source is compatible with the equipment. 7. Never open access doors to the unit while it is running. DANGER Always disconnect power before working on or near this equipment. Lock and tag the disconnect switch or breaker to prevent accidental power up. If this unit is equipped with optional gas accessories, turn off gas supply whenever power is disconnected. CAUTION This unit is equipped with a compressed refrigerant system. If a leak in the system should occur, immediately evacuate and ventilate the area. An EPA Certified Technician must be engaged to make repairs or corrections. Refrigerant leaks may also cause bodily harm. CAUTION When servicing the unit, the internal components may be hot enough to cause pain or injury. Allow time for cooling before servicing. 1 Model RT

2 Receiving/Inspection Upon receiving the product, check to make sure all items are accounted for by referencing the bill of lading to ensure all items were received. Inspect each crate for shipping damage before accepting delivery. Notify the carrier if any damage is noticed. The carrier will make notification on the delivery receipt acknowledging any damage to the product. All damage should be noted on all the copies of the bill of lading which is countersigned by the delivering carrier. A Carrier Inspection Report should be filled out by the carrier upon arrival and the Traffic Department. If damaged upon arrival, file claim with carrier. Any physical damage to the unit after acceptance is not the responsibility of FHP Manufacturing. Unpacking Verify that all required parts and the correct quantity of each item have been received. If any items are missing, report shortages to your local representative to arrange for obtaining missing parts. Sometimes it is not possible that all items for the unit be shipped together due to availability of transportation and truck space. Confirmation of shipment(s) must be limited to only items on the bill of lading. See also Installation/ Lifting. Handling Units are to be rigged and moved by the lifting brackets provided or by the skid when a forklift is used. Number and location of lifting brackets varies by model and size. Handle each piece in such a manner as to keep from scratching or chipping the coating. Damaged finish may reduce ability of the unit to resist corrosion. Storage Units are protected against damage during shipment. If the unit cannot be installed and operated immediately, precautions need to be taken to prevent deterioration of the unit during storage. The user assumes responsibility of the unit and accessories while in storage. The manufacturer will not be responsible for damage during storage. These suggestions are provided solely as a convenience to the user. Inspection and Maintenance during Storage While in storage, inspect units once per month. Keep a record of inspection and maintenance performed. If moisture or dirt accumulations are found on parts, the source should be located and eliminated. At each inspection, rotate all moving components by hand ten to fifteen revolutions to distribute lubricant on motor and bearings. If paint deterioration begins, consideration should be given to touch-up or repainting. Units with special coatings may require special techniques for touch-up or repair. Machined parts coated with rust preventive should be restored to good condition promptly if signs of rust occur. Immediately remove the original rust preventive coating with petroleum solvent and clean with lint-free cloths. Polish any remaining rust from surface with crocus cloth or fine emery paper and oil. Do not destroy the continuity of the surfaces. Wipe clean thoroughly with Tectyl 506 (Ashland Inc.) or the equivalent. For hard to reach internal surfaces or for occasional use, consider using Tectyl 511M Rust Preventive or WD-40 or the equivalent. 2 Model RT Energy Recovery Unit

3 Table of Contents General Description Models and Capacities Supplemental Installation, Operation and Maintenance Manuals Owners Information Product Overview Subassemblies Coils Dampers Energy Wheel Filters Heat Pump Module Optional Electric Heaters Optional Indirect Gas Furnace. 7 Operating Concerns Low Ambient Operation Reduced Airflow Environmental Concerns Installation Installation Concerns Unit Weights and Roof Opening Dimensional Data Access Door Description and Location Service Clearances Handling and Lifting Roof Curb Mounting / Dimensions / Weights.. 13 Rail Mounting / Layout Vibration Isolators Lifting Lug Removal Exhaust Weatherhood Ductwork Connections Drain Trap Plumbing Coil Application Recommendations Water Coils / Water Connections Heat Pump Airside Coils Electrical Information General Electrical Information Field Power Connection Control Center Components Optional Preheater Optional Post-Heater Post-Heater Control Panel Electric Heater Application / Operation Optional Service Outlet Optional Vapor Tight Lights Typical Wiring Diagram Microprocessor Controller Sequence of Operation Energy Wheel Sequence of Operation Electrical Controls Frost Control Application / Operation Timed Exhaust Frost Control Modulating Wheel Frost Control Economizer Application / Operation Modulating the Wheel Variable Frequency Drive (VFD) Optional Remote Control Panel and Schematics 27 Rotation Sensor Dirty Filter Sensor DDC Temperature Control Package Sensor Schematic Compressed Refrigeration System Heat Pump Overview Heat Pump Controls Heat Pump Fault Indicators Energy Recovery Wheel 34 Refrigeration Schematic 35 Typical Operating Conditions 35 Initial Start-up Procedure Start-Up Information/Checklist/Procedure Troubleshooting Airflow Unit Refrigeration Circuit Maintenance Overview Maintenance Frequency Maintenance Procedures Maintenance Log 51 Warranty Backcover Model RT Energy Recovery Unit 3

4 General Description The RT brings in fresh, outdoor air and removes stale exhaust air from the building. The intake and exhaust airstreams move through the RT in opposite directions in separate passages, and each airstream passes through an energy wheel. In cooling mode, the energy wheel removes both heat and moisture from the incoming airstream and rejects it into the exhaust airstream. In heating mode, the energy wheel removes heat and humidity from the exhaust air and rejects it into the intake air, thus reclaiming energy already expended to heat the building air. In addition to the energy wheel, the RT incorporates a heat pump that is connected to an airside coil inside the unit. This coil provides significant, highly efficient heating and cooling by using an outside water source as a heat sink. For purposes of providing temporary emergency heat, an optional secondary heating source such as indirect gas furnace, hot water coil or electric heaters may also be installed. Simply put, this unit preconditions the outdoor air to save money on heating and cooling costs and then provides supplemental heating and cooling by means of a highly efficient heat pump. Outdoor Air Intake Heat Pump Airside Heating and Cooling Coil Coaxial Refrigerant-to-Water Heat Exchanger Heat Pump Module (component locations will vary) Models and Capacities The RT is manufactured in four different platform sizes; 20, 45, 55 and 90. Each platform has multiple options for heating and cooling capacities. Every RT unit has an energy wheel which greatly boosts heating and cooling capacity of the heat pump and a number of additional factory-installed options are available to produce further increases. All 4, 5 and 6 ton capacity units have a single scroll type compressor and Heat Pump Capacity all other units have two scroll type compressors Unit Size Tons and use a split airside RT-20 4, 5, 6 heat pump coil. RT-45 8, 10, 12.5, 15 RT-55 15, 17.5, 20 RT-90 20, 25, 30 Supplemental Installation, Operation and Maintenance Manuals Refer to the following Installation, Operation and Maintenance Manuals for additional details: Part # Exhaust Weatherhood Part # RT Curb Assembly Instruction Part # Model PVF, Indirect Gas Fired Furnaces for Energy Recovery Units Additional manuals are available for each accessory used in the RT. These additional manuals are provided by the respective manufacturers and are included with unit shipment. Filters Energy Wheel Cassette Reheat Coil Supply Air Motor & Blower Heat Pump Compressor(s) 4 Model RT Energy Recovery Unit

5 Owner s Information The following summary highlights some important notes to help avoid premature failure and possible voidance of warranty. Product Overview FHP Manufacturing RT Models integrated with a heat pump system are designed with the purpose of being a self-contained source for heating and cooling in both commercial and institutional applications. This is done in a highly efficient manner through the use of a rotary air-to-air total enthalpy wheel called an energy wheel. The wheel allows the compressors and cooling equipment to be downsized in the unit, therefore being more cost effective to operate. The heat pump system comes from the factory fully charged with refrigerant and is ready for connection to a water source upon arrival. The smaller tonnage units (4-6 tons) contain a single compressor, allowing for one stage of cooling. Larger units (8-30 tons) come standard with two compressors and a split airside coil. This allows for staging of compressors to meet a wider range of outdoor air loads while reducing the amount of cycles per compressor. Subassemblies The following subassemblies are used or are optionally available in all models of the RT. RT Coils In the RT, there is only one coil that will be present in every unit and that is the airside coil. The airside coil is connected to the heat pump compressor(s) and is the primary vehicle for heating and cooling of the building. A reheat coil is optionally available and is installed in the supply air stream adjacent to the airside coil. The reheat coil is also connected to the heat pump but is used only when the unit is in cooling mode and its function is to control humidity in the conditioned air stream. It does this by reheating the chilled air coming from the airside coil and then delivering the dehumidified air at a neutral temperature to the space. A hot water coil is available as an option and is used for supplementary heat for the building. If present, this coil will be installed in the supply airstream, mounted vertically on the interior wall that separates the supply air blower and motor from the airside coil compartment. Optional Hot Water Coil Location RT Dampers There are four locations where dampers are optionally installed. If an exhaust weatherhood is installed, a gravity type damper is included with that fixture. Optional dampers may be located in the air stream and are always motorized. The exhaust damper and outside damper are either low leakage or insulated low leakage. There is one additional optional damper that permits 100% recirculation of exhaust air when the Outdoor Air damper is closed and the Exhaust Air Blower is off and is intended for use during unoccupied conditions. It is located in a vertical position on the interior wall separating the intake airstream from the exhaust airstream. Gravity Type Exhaust Damper Ooutdoor Air Hood Exhaust Hood Filters Wheel Cassette Motorized Outdoor Air Intake Damper Filters Coil Section Electrical Box Exhaust Air Intake Motorized Exhaust Air Damper Motorized Recirculating Air Damper RT Energy Wheel Every RT unit contains a rotary air-to-air total enthalpy wheel known as an energy wheel. The energy wheel rotates through both the incoming air and the exhaust air streams, removing both sensible (heat) energy and moisture from one airstream and transferring it to the other air stream. The energy wheel is incorporated into a subassembly known as an energy wheel cassette. The energy wheel itself is comprised of segments which can be removed for servicing or, in many cases, the entire cassette can be removed. The cassette consists of a rigid frame with bearings, a motor and the energy wheel. It is constructed and installed to prevent air leakage around the energy wheel, forcing the entire airstream to pass through the wheel. Adjustable Air Seals Drive Belt Indirect Gas Heater Bearing Support Label showing cassette serial # and date code Drive Pulley Heat Pump Airside Coil Optional Heat Pump Reheat Coil Model RT Energy Recovery Unit 5

6 RT Filters There are three locations in the RT where filters will be found. In the Outdoor Air Intake, there are permanent metal filters that are accessed by removing the filter access panel on the side of the louver assembly. The metal filters require regular cleaning, see Routine Maintenance section of this manual. In the outdoor air intake portion of the RT, a set of 2-inch thick MERV 8 or MERV 13 pleated filters are used. These filters are located directly in front of the energy wheel cassette and require frequent inspection and periodic replacement. See Routine Maintenance section of this manual. In the exhaust air intake stream there is an additional set of 2-inch thick MERV 8 or MERV 13 pleated filters. These filters are located between the exhaust air intake and the energy wheel cassette. See Routine Maintenance section of this manual. Ooutdoor Air Hood Exhaust Hood Filters Wheel Cassette Filters Coil Section Permanent Metal Filters Two-inch thick MERV 8 or MERV 13 pleated filters Electrical Box Exhaust Air Intake Indirect Gas Heater RT Heat Pump Module Every RT has an integral heat pump module that contains hermetic scroll-type compressor(s), a coaxial refrigerant-to-water heat exchanger(s), refrigerant flow reversing valve(s), expansion valve(s), liquid line filter drier, high pressure manual reset cutout, crankcase heater(s) and various sensors, service ports and safety devices which allows the unit to run at less than full capacity and results in fewer compressor cycles. The heat pump is intended to be connected to an external water source such as a water cooling tower or boiler, a geothermal source or even a ground loop. The module is piped to the airside coil located in the intake airstream and optionally to a reheat coil that will control humidity. The location of components in the module will vary. Control circuitry and the Unit Protection Module (UPM) for the heat pump module are located in the heat pump module. The UPM is a printed circuit board and has LED fault indicator lights to indicate various alarm conditions and also power status. A unit-specific schematic for electrical circuits is located in the Control Unit Protection Module (UPM) Center and another unit-specific schematic for heat pump circuitry is located in the heat pump module. See also the Typical Refrigerant Flow Schematic in this IOM. In normal use, the heat pump module requires only periodic inspection and cleaning. Any servicing or repairs must be performed by an EPA Certified Technician. High Efficiency Scroll Type Compressors Refrigerant Reversing Valves Coaxial Refrigerantto-Water Heat Exchangers Water Intake and Discharge Connections RT Heat Pump Module 6 Model RT Energy Recovery Unit

7 RT Optional Electric Heaters There are two optional electric heaters available for the RT. One is a preheater and is used to prevent frost buildup on the energy wheel. It is located directly in front of the intake air filter assembly. The second optional heater is used as a supplementary emergency heat source for the building and is integrated into the supply air stream by installing the heater in a vertical position on the interior wall separating the coil compartment from the supply air motor and blower compartment. Optional Electric Preheater Location Optional Electric Heater Location RT Optional Indirect Gas Furnace An optional Indirect Gas furnace may be installed in the RT and its function is to provide supplementary emergency heat to the building. The Model PVF Indirect Gas Furnace is installed into the supply air stream by means of raising the supply air motor and blower assembly and installing that assembly directly on top of the furnace. An additional housing is installed on the end of the RT module, providing access to the burners, vest plate and furnace circuitry. A complete IOM for the furnace as well as a unit-specific wiring diagram are located inside the furnace housing access door. Supply Air Motor and Blower Assembly Supply Air Motor and Blower Assembly Model PVF Indirect Gas Furnace Furnace Housing with access to burners, vest plate and circuitry Model RT Energy Recovery Unit 7

8 Operating Concerns Low Ambient Operation Care has been taken to ensure low ambient operation does not cause damage to the refrigerant system. A factory-installed temperature sensor in the outdoor air intake prevents refrigerant system operation at ambient conditions below 55ºF. Crankcase heaters will still be engaged provided the main power has not been disconnected. If cooling is desired at ambient temperatures below 55ºF, economizer operation (wheel start/stop or wheel modulation) should be employed. Reduced Airflow pumping oil and liquid refrigerant Lack of maintenance will lead to filters and airside coils building-up with dirt and debris. As this occurs, the airflow through the unit will decrease. Airside coils are sized to handle a particular airflow volume and a reduction in airflow can cause the airside coils to get too cold. As this happens, ice buildup on the face of the coil is possible, further reducing airflow. The result of the airside coil operating at temperatures below design limits, is that excessive liquid refrigerant will be returned to the compressor(s). The liquid refrigerant buildup in the compressor(s) will displace the necessary oil needed for proper lubrication. The combination of these two events will significantly reduce the life of the compressor(s) and could result in compressor failure. To maintain the proper airflow and system efficiency, follow all procedures in the Maintenance section. Environmental Concerns This equipment contains R-410A refrigerant. It provides performance similar to that of R-22 refrigerant, but it offers a great advantage. It is an HFC refrigerant and does not contain any ozone depleting HCFC s or CFC s. When working with FHP fully charged refrigerant systems, it is strongly recommended that caution is undertaken during installation, operation, and routine maintenance. Systems using R-410A refrigerant operate at significantly higher pressures and R-22 service equipment or components should not be used on R-410A refrigerant systems. To comply with the U.S. Clean Air Act, anytime there is residual refrigerant, the proper equipment shall be used and methods should be followed to reclaim the refrigerant so that it can be recycled, reprocessed, or destroyed. IMPORTANT Do not release refrigerant to the atmosphere! If required service procedures include the adding or removing of refrigerant, the service technician must comply with all federal, state and local laws. The procedures discussed in this manual should only be performed by a qualified EPA Certified Technician. CAUTION Unit is designed for outdoor or indoor installation. Follow all guidelines in this manual for proper installation. 8 Model RT Energy Recovery Unit

9 Installation Concerns The RT will most often be installed on a rooftop but in some cases it may be preferable to install the unit at ground level beside the building, or even indoors. This portion of the IOM applies directly to roof top installations but most of the concerns remain the same regardless of where the unit is installed. Determine the best location, taking into consideration proper air movement around the unit, proper support of the unit and space around the unit for periodic maintenance. Refer to architect / engineer s instructions in the plans and specifications. Verify the load bearing capacity where the unit is to be installed and make certain that supporting structural members will not conflict with openings needed for ductwork. The RT must be elevated to isolate it from certain weather/temperature conditions and to permit proper installation of a condensate P trap and drain. Some installations will use FHP model GKD roof curb and an installation manual is included with it. It is preferable that the GKD roof curb be installed prior to installation of roofing membrane so that the curb can be properly flashed. If the owner chooses to fabricate a base in the field from materials supplied by others, observe all area building codes and use industry Best Practices to accomplish proper unit support and elevation. See also Rail Installations in this manual. If more than one unit is to be installed, make certain that the discharge air from one unit is not directed toward the outdoor air intake of any other unit. Clearance for exhaust air and return air ducts may be accomplished either by cutting individual duct openings or by opening the entire space within the roof curb unit. If the entire space within the curb is opened, higher radiated sound levels may result. Whenever supply or warm air ducts pass through a combustible roof, clearance of at least one inch (25 mm) must be maintained between the outside surfaces of the ductwork and any combustible materials in accordance with NFPA Standard 90. Installation The system design and installation should follow accepted industry Best Practices, such as described in the ASHRAE Handbook. Adequate space should be left around the unit for piping coils and drains, filter replacement, and maintenance. Sufficient space should be provided on the side of the unit for routine service and component removal should that become necessary. See Service Clearances/Access Panel Locations section for more details. Unit Weights and Recommended Roof Opening Exhaust Intake Supply Discharge Unit Size U V Approximate Weight (pounds) RT RT RT RT All dimensions are in inches. Unit weights assume rooftop configuration with weatherhoods, filters, outdoor air damper, six row DX coil, integral condensing section and an indirect gas-fired furnace. V 1/2 inch U 1/2 inch 1/2 inch Position the unit roof opening such that the supply discharge and exhaust inlet of the unit will line up with the corresponding ductwork. Be sure to allow for the recommended service clearances when positioning opening (see Service Clearances). Do not face the outdoor air intake of the unit into prevailing wind and keep the intake away from any other exhaust fans. Likewise, position the exhaust discharge opening away from outdoor air intakes of any other equipment. Model RT Energy Recovery Unit 9

10 Dimensional Data Overall Exterior Dimensions Model Width (including Lifting Lugs) Overall Width (with Exhaust Hood) Overall Length (with Outdoor Air Hood) RT RT RT RT All dimensions shown are in inches. Access Door Description and Location Following is a list of items accessible through the access doors shown on the diagrams. Some items are optional and may not have been provided. 1. Heat Pump and Unit Protection module (2 doors) Coaxial heat exchanger 2. Control Center with all electrical controls 3. Exhaust air filters Exhaust air intake damper (optional) Control panel and fuses for optional electric post-heater Energy wheel access Bypass damper (optional) 4. Exhaust motor and blower 5. Permanent aluminum filters (access panel located on intake hood) 6. Energy wheel and motor, belt and seals Outdoor air filters Outdoor air intake damper (optional) Frost control sensors (optional) Economizer sensors (optional) Electric preheater (optional) 7. Airside coil access Drain pan 8. Outdoor air blower / motor (if equipped with optional (IG furnace) 9. Outdoor air blower / motor / electric post-heater (if equipped with optional electric post-heater) Model RT with Heat Pump Outdoor Air Intake 3 5 Exhaust Weatherhood 4 10 Model RT Energy Recovery Unit

11 Service Clearances RT-20, -45, -55, and -90 units require minimum clearances for access on all sides for routine maintenance. Filter replacement, drain pan inspection and cleaning, energy wheel cassette inspection, fan bearing lubrication and belt adjustment are examples of routine maintenance that must be performed. Blower and motor assemblies, energy wheel cassette, coil and filter sections are always provided with a service door or panel for proper component access. Clearances for component removal may be greater than the service clearances, refer to drawings for these dimensions. RT-20 RT-45 EXHAUST HOOD 36 IN ACCESS PANEL ACCESS PANEL ACCESS PANEL ACCESS PANEL ELECTRICAL BOX 36 IN ACCESS PANEL OUTDOOR AIR HOOD FILTERS WHEEL CASSETTE FILTERS COIL SECTION EXHAUST AIR INTAKE IG HEATER 36 IN MINIMUM 52 IN CLEARANCE WITH IG HEATER ACCESS PANEL ACCESS PANEL *48 IN **64 IN ACCESS PANEL Clearances for service and component removal on RT-20 and RT-45 * Clearance for energy wheel removal on RT-20 ** Clearance for energy wheel removal on RT-45 RT-55 RT-90 EXHAUST HOOD 42 IN ACCESS PANEL ACCESS PANEL ACCESS PANEL ACCESS PANEL ELECTRICAL BOX 42 IN ACCESS PANEL OUTDOOR AIR HOOD FILTERS WHEEL CASSETTE FILTERS COIL SECTION EXHAUST AIR INTAKE IG HEATER 36 IN MINIMUM 52 IN CLEARANCE WITH IG HEATER ACCESS PANEL ACCESS PANEL 42 IN ACCESS PANEL Clearances for service and component removal on RT-55 and RT-90 Model RT Energy Recovery Unit 11

12 Handling While this unit was constructed with quality and dependability in mind, damage still may occur during handling of the unit for installation. Exercise extreme caution to prevent any damage from occurring to the refrigerant system. This unit contains a system pressurized with refrigerant that if damaged, could leak into the atmosphere or cause bodily harm due to the extreme cold nature of expanding refrigerant. Use protective equipment such as gloves and safety glasses to minimize or prevent injury in case of a system leak during installation. The system design and installation should follow accepted industry practice, such as described in the ASHRAE Handbook. Adequate space should be left around the unit for piping coils and drains, filter replacement, and maintenance. Sufficient space should be provided on the side of the unit for routine service and component removal should that become necessary. See Service Clearances/Access Panel Locations section for more details. Lifting 1. Before lifting, be sure that all shipping material has been removed from unit. 2. To assist in determining rigging requirements, weights are shown below. 3. Unit must be lifted by all lifting lugs provided on base structure. 4. Rigger to use suitable mating hardware to attach to unit lifting lugs. 5. Spreader bar(s) must span the unit to prevent damage to the cabinet by the lift cables. 6. Always test-lift the unit to check for proper balance and rigging before hoisting to desired location. 7. Never lift units by weatherhoods. 8. Never lift units in windy conditions. 9. Preparation of curb and roof openings should be completed prior to lifting unit to the roof. 10. Check to be sure that gasketing has been applied to the curb prior to lifting the unit and setting on curb. 11. Do not use fork lifts for handling unit. Warning All factory provided lifting lugs must be used when lifting the units. Failure to comply with this safety precaution could result in property damage, serious injury, or death. Unit weights assume rooftop configuration with weatherhoods, filters, outdoor air damper, six row DX coil, integral condensing section and an indirect gas fired furnace. 12 Model RT Energy Recovery Unit

13 Roof Curb Mounting Rooftop units require curbs to be mounted first. The duct connections must be located so they will be clear of structural members of the building. 1. Factory Supplied Roof Curbs: Roof curbs are Model GKD, which are shipped in a knockdown kit (includes duct adapter) and require field assembly (by others). Assembly instructions are included with the curb. 2. Install Curb: Locate curb over roof opening and fasten in place. (Refer to Recommended Roof Openings). Check that the diagonal dimensions are within ±1/8 inch of each other and adjust as necessary. For proper coil drainage and unit operation, it is important that the installation be level. Shim as required to level. 3. Install Ductwork: Installation of all ducts should be done in accordance with SMACNA and AMCA guidelines. Duct adapter provided to support ducts prior to setting the unit. 4. Set the Unit: Lift unit to a point directly above the curb and duct openings. Guide unit while lowering to align with duct openings. Roof curbs fit inside the unit base. Make sure the unit is properly seated on the curb and is level. Curb Outside Dimensions and Curb Weights (lbs) Unit Size L W Weight RT RT RT RT All dimensions are in inches. Weights are for 12 inch high curbs. Roof curb details, including duct locations dimensions are available on RT roof curb assembly instructions, part # Curb Outside Dimensions and Weights SIDE OF UNIT Curb Cap Dimensions Unit Size A B C D E RT RT RT RT All dimensions are in inches. B C D A E ROOF CURB BASE 1 INCH INSULATION Curb Cap Details for Factory Supplied Roof Curbs Rail Mounting / Layout Rails designed to handle the weight of the RT should be positioned as shown on the diagram (rails by others). Make sure that rail positioning does not interfere with the supply air discharge opening or the exhaust air intake opening on the RT unit. Avoid area dimensioned B below. Rails should run the width of the unit and extend beyond the unit a minimum of 12 inches on each side. Set unit on rails. Outdoor Air Intake Hood Isometric view of unit on rails Supply/Exhaust Opening B A Side view of unit on rails Rail Mounting Unit Size A B Curb Outside Dimensions RT RT RT RT All dimensions are in inches. Model RT Energy Recovery Unit 13

14 Vibration Isolators Note Many motor / blower assemblies include optional spring vibration isolation devices. When these isolation springs are used, the motor / blower assembly is secured for shipment by compressing the springs and securing the assembly to intermediate rails (see photo). NOTE On some models of the RT, one lifting lug may be positioned directly in front of the condensate drain connection. See illustration. Spring Isolation Device Motor / Blower Assembly in shipping position Upon receipt, visually inspect motor / blower assemblies to verify presence of spring isolation devices. If they are present, carefully remove shipping restraints to allow free movement of assembly. CAUTION Intermediate Shipping Rail (typical) These assemblies are shipped with the springs in a compressed state and when shipping restraints are removed, the assembly will bounce upward. Do not position hands or fingers where they may be pinched or injured by sudden movement of the assembly. The method of compressing and restraining the motor / blower assembly varies with each product. If sheet metal screws or bolts are used, they are installed with an equal number on both the front and the rear of each assembly. Screws or bolts used on the rear rail of the assembly are difficult to see. It is recommended that the rear screws or bolts be removed prior to the front ones in order to reduce the chance of injury. If restraining bands are used instead of screws or bolts, carefully cut and remove the bands. Any lifting lug that is located as shown should be removed in order to permit installation of the P trap drain kit. Exhaust Weatherhood The exhaust weatherhood is shipped separately as a kit with its own instructions. Ductwork Connections Examples of poor and good fan-to-duct connections are shown below. Airflow out of the fan should be directed straight or curve the same direction as the fan wheel rotates. Poor duct installation will result in low airflow and other system POOR effects. Rotation Length of Straight Duct GOOD Rotation Recommended Discharge Duct Size and Length Model Blower Size Duct Size Straight Duct Length RT x RT x RT x RT x All dimensions shown in inches. Recommended duct sizes are based on velocities across the cfm range of each model at approximately 800 feet per minute (FPM) at minimum airflow and up to 1600 fpm at maximum airflow. Recommended duct sizes are only intended to be a guide and may not satisfy the requirements of the project. Refer to plans for appropriate job specific duct size and/or velocity limitations. Straight duct lengths were calculated based on 100% effective duct length requirements as prescribed in AMCA Publication 201. Calculated values have been rounded up to nearest foot. 14 Model RT Energy Recovery Unit

15 Drain Trap The RT is equipped with a stainless steel condensate pan with a stainless steel drain connection. It is important that the drain connection be fitted with a P trap to ensure proper drainage of the RT while maintaining internal static pressures and to prevent migration of sewer gas back into the unit. A P trap assembly (kit) is supplied with the unit and is to be assembled and installed as local conditions require and according to the assembly instructions provided with the P trap. If local and area building codes permit, the condensate may be drained from the P trap onto the roof, but a drip pad should be provided beneath the outlet. If local and area codes require a permanent drain line, it should be fabricated and installed in accordance with Best Practices and all codes. In some climates it will be necessary to provide freeze protection for the P trap and drain line. The P trap should be kept filled with water or glycol solution at all times and it should be protected from freezing to protect the P trap from damage. If severe weather conditions occur, it may be necessary to fabricate a P trap and drain line of metal and install a heat tape to prevent freezing. Drain Trap Assembly Kit Model RT Energy Recovery Unit 15

16 Plumbing Coil Application Recommendations Factory installed cooling and heating components are mounted in the coil section of the unit. The coil section is downstream of the energy wheel on the supply airside of the unit. Note the coil connection locations on the picture. Airside coil connections are located internal to the unit as shown. Hot water coil connections Coil access door Water Coils Water coils are a design option that must be specified for factory installation. A water coil may be used for further tempering of the outdoor air. If used, the optional hot water coil would be located vertically on the internal cabinet partition that separates the airside coil from the supply air blower compartment of the RT. See also Subassemblies/Coils. 1. Piping should be in accordance with accepted industry standards. Pipework should be supported independently of the RT unit. Water connections are male NPT iron pipe. When installing couplings, do not apply undue stress to the connection extending through the unit. Use a backup pipe wrench to avoid breaking the weld between coil connection and header. 2. Connect the water supply to the bottom connection on the air leaving side and the water return to the top connection on the air entering side. To ensure proper venting, an external air vent in the piping is recommended. Connecting the supply and/or return in any other manner will result in very poor performance. Be sure to replace factory installed grommets around coil connections if removed for piping. Failure to replace grommets will result in water leakage into the unit and altered performance. 3. The air vent at the uppermost point should be temporarily opened during system start-up to release all of the air from the coil. To maintain heat transfer capacity, periodically vent any air in coil. 4. Water coils are not normally recommended for use with entering air temperatures below 40ºF; however, the energy wheel maintains a pre-coil temperature higher than 40ºF. No control system can be depended on to be 100% safe against freeze-up with water coils. Glycol solutions or brines are the only safe media for operation of water coils with low entering air conditions. Continuous water circulation through the coil at all times is highly recommended. 5. Pipe sizes for the system must be selected on the basis of the head (pressure) available from the circulation pump. The velocity should not exceed 6 feet per second and the friction loss should be approximately 3 feet of water column per 100 feet of pipe. Heat Pump Airside Coils Outdoor air entering the RT is first tempered by the energy wheel and then passes through the heat pump airside coil for further heating or cooling. Refrigerant in a vapor state will circulate through the airside coil whenever the heat pump is operating, but the direction of flow will change, depending on whether the unit is in cooling or heating mode. When the unit is operated in the cooling mode, a significant amount of condensate will be produced and then collected in the stainless steel condensate drain pan. The condensate drain pipe should be sized adequately to ensure the condensate drains properly. Refer to Drain Trap section. 16 Model RT Energy Recovery Unit

17 Electrical Information Warning: DO NOT penetrate the roof of the unit for any reason since there are hazardous voltage circuits located between the inner and outer roof panels. The unit must be electrically grounded in accordance with the current National Electrical Code, ANSI/NFPA 70. In Canada, use current CSA Standard C22.1, Canadian Electrical Code, Part 1. In addition, the installer should be aware of any local ordinances or electrical company requirements that might apply. System power wiring must be properly fused and conform to the local and national electrical codes. System power wiring is to the unit main disconnect (door interlocking disconnect switch standard on most units) or distribution block and must be compatible with the ratings on the nameplate: supply power voltage, phase, and amperage (Minimum Circuit Amps - MCA, Maximum Overcurrent Protection - MOP). All wiring beyond this point has been done by the manufacturer and cannot be modified without affecting the unit s agency / safety certification. If field installing an additional disconnect switch, it is recommended that there is at least four feet of service room between the switch and system access panels. When providing or replacing fuses in a fusible disconnect, use dual element time delay fuses and size according to the rating plate. Field Power Connection: The RT is designed for simple, single-point connection (in the Control Module) for high voltage supply. In addition to high voltage power supply, it will be necessary to run low voltage controller circuitry to the terminal strip in the Control Center. In some cases, a second high voltage circuit will be required to power a high capacity electric post heater. Refer to unit-specific wiring diagram for further details. Many RT units will not have any internal circuit fuses. Some large units may have circuit fusing and those fuses will be present on the high voltage side of the Control Center. Optional electric post heaters may be fused and those fuses are located on the post heater control panel. In all cases, refer to the unit-specific wiring diagram. Once high voltage power is connected to the unit it still will not operate unless a controller is installed on terminals R and G of the terminal strip. Do not install any controller circuit or jumper on the R and G terminals until ready for the Startup Procedure. The recommended location for entry of electrical circuits and high voltage supply wiring is through the floor of the unit, preferably in the area of the Control Center. Carefully select a location that does not interfere with other controls or assemblies such as the motorized dampers. Seal penetration in cabinet bottom to prevent leakage. The electric supply to the unit must meet stringent requirements for the system to operate properly. Voltage supply and voltage imbalance between phases should be within the following tolerances. If the power is not within these voltage tolerances, contact the power company prior to operating the system. Voltage Supply: See voltage use range on the rating plate. Measure and record each supply leg voltage at all line disconnect switches. Readings must fall within the allowable range on the rating plate. Voltage Imbalance: In a 3-phase system, excessive voltage imbalance between phases will cause motors to overheat and eventually fail. Maximum allowable imbalance is 2%. To determine voltage imbalance, use recorded voltage measurements in this formula. Key: V1, V2, V3 = line voltages as measured VA (average) = (V1 + V2 + V3) / 3 VD = Line voltage (V1, V2 or V3) that deviates farthest from average (VA) Formula: % Voltage Imbalance = [100 x (VA-VD)] / VA CAUTION If any of the original wire as supplied with the appliance must be replaced, it must be replaced with wiring material having a temperature ratings of at least 105 C. WARNING To prevent injury or death due to electrocution or contact with moving parts, lock disconnect switch open. For units with a gas furnace, if you turn off power supply, turn off gas. Most factory supplied electrical components are prewired. To determine what electrical accessories require additional field wiring, refer to the unit specific wiring diagram located on the inside of the unit control center access door. The low voltage control circuit is 24 VAC and control wiring should not exceed 0.75 ohms. Refer to Field Control Wiring Length/Gauge table for wire length maximums for a given wire gauge. Field Control Wiring Length/Gauge Total Wire Length Minimum Wire Gauge 125 ft ft ft ft. 12 Control wires should not be run inside the same conduit as that carrying the supply power. Make sure that field supplied conduit does not interfere with access panel operation. If wire resistance exceeds 0.75 ohms, an industrialstyle, plug-in relay should be added to the unit control center and wired in place of the remote switch (typically between terminal blocks R and G on the terminal strip (refer to Typical Control Center Components). The relay must be rated for at least 5 amps and have a 24 VAC coil. Failure to comply with these guidelines may cause motor starters to chatter or not pull in which can cause contactor failures and/or motor failures. Model RT Energy Recovery Unit 17

18 Typical Control Center Components - individual components and locations will vary 1. Main Disconnect (non-fusible, lockable) 2. Motor Starter - Exhaust Air Fan 3. Motor Starter - Outdoor Air Fan 4. Motor Contactor - Energy Wheel Vac Control Transformer Vac Terminal strip 7. Fuses for blower motors 8. Grounding lug 9. Distributor block 10. Compressor fuse blocks 11. Compressor contactors 12. Condensing fan contactors 13. Compressor cycle timers 14. Compressor relay 15. Terminal block Optional Control Center Components 16. DDC controller 17. Dirty filter pressure switches 18. Economizer module 19. Thermostats for: - Economizer module - Energy Recovery wheel frost control - Compressor lock out 20. Terminal block 21. Frost control pressure switch 22. Energy recovery wheel VFD Component #6 Exploded Detail of Terminal Strip Refer to Heat Pump System section for components in compressor compartment Access to Control Center Components is gained through the access panel indicated. 18 Model RT Energy Recovery Unit

19 Optional Accessories Preheaters: Preheaters are standard as two-stage, step control. Step control heaters are designed with multiple stages made up of equal increments of heating capability. For example, a 10 kw heater with two stages will be composed of two 5 kw stages. Preheaters are single point wired at the factory. A temperature sensor (with field adjustable set point) is mounted in the outdoor airstream after the preheater to turn the preheater on. See Frost Control Application/Operation for typical set points. If the temperature falls below the set point and the wheel pressure drop sensor is triggered, the first stage of the preheater will turn on. If the first stage does not satisfy the set point, the second stage will also turn on. See also Subassemblies/Electric Heaters Post-heaters: Post-heaters are standard as SCR control; see unit specific wiring diagram. A temperature sensor (with field adjustable set point) is mounted in the outdoor airstream after the postheater to turn the post-heater on. A SCR heater provides an infinitely modulating control of the heat to provide an accurate discharge temperature. A call for heat is required. Post-Heater Control Panel: The post-heater is not single point wired to the RT control center. Separate power must be supplied to the postheater disconnect (located in unit control center). See Access Door Descriptions and Locations for access to post-heater control panel. For Model RT, the exhaust filters must be removed from the unit to access. Electric Heater Application/Operation Factory installed electric heaters may be optionally supplied for energy wheel preheating. The optional electric preheater is positioned upstream of the air intake filters and its primary function is to prevent frost accumulation on the energy wheel. Electric heaters are available in 208, 230, or 460 VAC (refer to heater nameplate for voltage). An optional tempering electric heater may be installed as a supplementary heat source and is located as shown in Subassemblies/Optional Electric Heat. Service Outlet 120 VAC GFCI service outlet ships loose for field installation. Requires separate power source so power is available when unit main disconnect is turned off for servicing. Vapor Tight Lights Vapor tight lights provide light to each of the compartments in the energy recovery unit. The lights are wired to a junction box mounted on the outside of the unit. The switch to turn the lights on is located in the unit control center. The switch requires a separate power source to allow for power to the lights when the unit main disconnect is off for servicing. Model RT Energy Recovery Unit 19

20 Typical Wiring Diagram Following is an example of a typical wiring diagram located in the unit control center. This wiring diagram includes a legend highlighting which accessories were provided with the unit. Factory wiring and field wiring are also indicated. This particular example includes 1) variable frequency drives on the blowers requiring a modulating input, 2) modulating energy recovery wheel with factory controls for economizer, 3) energy wheel rotation sensor, 4) outdoor air and exhaust air dirty filter switches, 5) motorized outdoor air and exhaust air intake dampers, and 6) timed exhaust frost control. Many other factory installed and wired accessories are available. 20 Model RT Energy Recovery Unit

21 Microprocessor Controller Sequence of Operation Microprocessor Controller This unit is typically provided with a microprocessor controller (called a DDC) that is factory programmed, mounted and tested. The controller has an LCD screen to provide for easy monitoring of unit operation and changing set points. Factory-installed sensors are already mounted and wired, but there are several optional sensors and control devices that must be field-installed. See also the unit-specific wiring diagram and the manual supplied with the microprocessor controller. Unit Start Command: Factory mounted and wired Outdoor air (D1) and Exhaust air (D2) damper actuators are powered. Exhaust fan starts after a 10-second delay (adjustable). Supply fan starts 5 seconds (adjustable) after the exhaust fan. Heating, cooling and wheel operation per below. Unit Stop Command (or De-Energized): Supply fan, exhaust fan, tempering options and wheel are de-energized. Outdoor Air and Exhaust Air damper actuators are de-energized and dampers will close. Remote On / Off Unit DDC shall have an input allowing the unit to be started/stopped by others. Occupied / Unoccupied Modes Shall be based on a 7-day time clock internal to the controller. The schedule shall be set by the end user. When a user initiates an override input, the DDC would switch from unoccupied to occupied mode. The DDC will return to the scheduled occupied/ unoccupied mode after the override time has expired (60 min, adjustable). If internal time clock is disabled, a remote contact or a BMS can control the occupied/ unoccupied mode. Occupied Mode 1. Supply fan ON. 2. Exhaust fan ON. 3. Heating per below. 4. Cooling per below. 5. Wheel control per below. Unoccupied Mode (Unit Off) Default setting when there is no recirculation damper or room temperature sensor Unoccupied mode (Cycle on Room) Optional unoccupied mode when there is a recirculation damper and a room temperature sensor wired to unit. 1. Exhaust fan off 2. Supply fan off 3. Recirculation air damper open. 4. OA Damper Closed 5. On a call for heating (room temp set point differential, 65 F - 5 F = 60 F) supply fan cycles on, and the heating increases the room temperature. Unit cycles off when room temperature reaches the unoccupied set point (65 F, adjustable). 6. On a call for cooling (room temp set point + differential, 85 F + 5 F = 90 F) supply fan cycles on, and the cooling decreases the room temperature. Unit cycles off when room temperature reaches the unoccupied set point (85 F, adjustable) Cooling Sequence DDC will power the reversing valve within the heat pump module to direct the refrigerant flow for airside cooling. The cooling is controlled to maintain the supply temperature set point. The mechanical cooling will be locked out when the outside air is < 55 F - 2 F hysteresis, adjustable. Water Source Heat Pump Cooling: DDC will provide a digital signal for 1 or 2 stages of cooling to maintain the supply air set point (adj.). This signal will come wired to the factory provided condensing section. Dehumidification Sequence DDC will power the reversing within the heat pump module to direct the refrigerant flow for airside cooling. The cooling is controlled to maintain the cooling-coil set point. The dehumidification sequence will be locked out when the OA is <10 F above the cold-coil set point. The mechanical cooling will be locked out when the outside air is < 55 F - 2 F hysteresis, adjustable. Water Source Heat Pump Cooling: DDC will provide a digital signal for 1 or 2 stages of cooling to maintain the supply air set point (adj.). This signal will come wired to the factory provided heat pump module. Reheat Sequence While the unit is in dehumidification mode, the outdoor air can be reheated via Modulating Hot Gas Reheat for space neutral applications. Modulating Hot Gas Reheat: The controller will send a 0-10 V signal to the modulating hot gas reheat valve to maintain the supply temperature set point (adjustable). Model RT Energy Recovery Unit 21

22 Heating Sequence The heating is controlled to maintain the supply temperature set point. The heating will be locked out when the outside air is > 70 F + 2 F hysteresis, adjustable. Water Source Heat Pump Heating: DDC will provide a digital signal for 1 or 2 stages of heating to maintain the supply air set point (adjustable). This signal will come wired to the factory provided heat pump module. Auxiliary Heating Sequence The auxiliary heating is controlled to maintain the auxiliary heating set point. The auxiliary heating will be locked out when the after coil temperature is greater than 50 F. The DDC must also be calling for a second stage of heating to activate the auxiliary heat through a relay. Indirect Gas Furnace: A factory mounted thermostat (de-coupled from DDC) will operate the indirect gas furnace to maintain the auxiliary heating set point of 70 F. Electric Heater: A factory mounted thermostat (de-coupled from DDC) will operate electric heater to maintain the auxiliary heating set point of 70 F. Supply Set Point Reset Function Either a room temperature sensor or the outdoor air reset function (if no room temperature sensor wired to controller) will determine the supply temperature of the unit. Outdoor Air Reset Function: With no room temperature sensor available, the controller will default to discharge temperature control based on outdoor air temperature. The controller will monitor the OA temperature and reset the supply temperature set point based upon the outdoor air reset function. Optional Room Temperature Sensor: With a room temperature sensor, the controller will adjust the supply temperature set point up/ down accordingly to satisfy the desired room temperature. Cooling and heating are determined by a difference in temperature of the room temperature sensor compared to the desired room temperature set point (adjustable) Building Freeze Protection If the supply air temperature drops below 35 F (adjustable), the DDC will de-energize the unit and activate the alarm output after a preset time delay. Heat Pump Low Temperature Protection If the post-wheel temperature sensor drops below 40 F for a period of 10 minutes, the heat pump module will be de-energized to protect the system. 22 Model RT Energy Recovery Unit

23 Energy Wheel Sequence of Operation Optional Economizer Stop Wheel: When economizer mode is enabled and there is a signal for cooling, the wheel will stop rotating to allow free cooling. Modulate Wheel: When economizer mode is enabled and there is a signal for cooling, the wheel VFD modulates wheel speed to maintain the discharge temperature set point. The economizer will be locked out when: the outside air is <40 F (- 2 F hysteresis, adjustable); the unit is operating in dehumidification mode; or there is a call for heating. Optional Frost Control - The DDC controller will output a signal when wheel frosting is occurring which is determined by a temperature set point (OA <5 F 2 F hysterisis, adjustable) and wheel pressure drop increase. Preheat: When frosting is occurring, the preheater is energized to defrost the wheel. Once the pressure drop decreases below the set point, the preheater is de-energized. Timed Exhaust: When frosting is occurring, the supply blower is cycled off along with the heat pump module for 10 minutes. The exhaust blower shall continue to run allowing the warm exhaust air to defrost the wheel. After the 10 minute cycle, the supply fan and heat pump are re-energized to continue normal operation. Alarms Indication - DDC shall have one digital output for remote indication of an alarm condition. Possible alarms include: Dirty Filter Alarm: If the outside air or return air filter differential pressure rises above the switch set point (adjustable), the differential pressure switch shall signal the DDC to activate an alarm. Wheel Rotation Alarm: Monitors wheel rotation, and sends a signal to controller (after a 15 second time delay with no rotation) that signals the DDC to activate an alarm. Supply and Exhaust Air Alarm: DDC monitors proving switch on each blower and displays an alarm in case of blower failure. Dirty Wheel Alarm: DDC monitors pressure across the wheel and sends an alarm in the case of an increased pressure drop. DX Alarm: DDC monitors the refrigerant pressure and shuts off refrigeration circuit in the case of high or low refrigerant pressure. Temperature Sensor Alarm: DDC will send an alarm in the case of a failed air temperature sensor. Heat Pump Alarm: The UPM board controlling the heat pump module will send an error signal to the DDC which will then output a non-fatal, generic alarm message. Optional Accessories The following accessories can be ordered with the unit to expand the functionality or usability of the controller. Room Temperature Sensor (TS): The room temperature sensor is a field mounted sensor that can provide a real-time temperature of the space being served. The user will input a desired room temperature setting, and the controller will adjust the discharge temperature of the unit to compensate for changes in room temperature. Room Dehumidistat (S8): The room dehumidistat is a field mounted sensor that can monitor the relative humidity (RH) of the space. If the RH exceeds 60% RH, the dehumidistat will send a digital signal to the controller to decrease the after-cooling coil temperature. The DDC will control the cooling type to achieve the lower after-coil temperature until the space dehumidistat is satisfied. BMS Interfacing: A BMS serial card is provided with the controller for field interfacing with a building management system. Each card is sent out with the default parameters, and the controls contractor must change the appropriate addresses to match the BMS settings. DDC Remote Interface: An interface panel that can be wired to the main controller for remote adjustments of set points. Model RT Energy Recovery Unit 23

24 Frost Control Application/Operation Extremely cold outdoor air temperatures can cause moisture condensation and frosting on the enthalpy wheel. Frost control is an optional feature that will prevent/control wheel frosting. Three options are available: 1. Timed Exhaust frost control 2. Electric preheat frost control 3. Modulating wheel frost control All of these options are provided with a thermostat (with probe) mounted in the outdoor air intake compartment and a pressure sensor to monitor pressure drop across the enthalpy wheel. The typical temperature setting corresponds to the indoor air relative humidity as shown in the Frost Threshold Temperatures Table and represents when frost can occur. An increase in pressure drop would indicate that frost is occurring. Both the pressure sensor and the outdoor air temperature sensor must trigger in order to initiate frost control. The two sensors together ensure that frost control is only initiated during a real frost condition. Field wiring of a light (or other alarm) between 6 & C in the control center will notify personnel when unit is in frost control mode (refer to Remote Panel Wiring schematics section for wiring details). The following explains the three options in more detail. Timed exhaust frost control includes a timer in addition to the thermostat and wheel pressure sensor. When timed exhaust frost control is initiated, the timer will turn the supply blower on and off to allow the warm exhaust air to defrost the enthalpy wheel. Default factory settings are 5 minutes off and 30 minutes on. Use the following test procedure for troubleshooting. Testing (refer to Timer A1 B1 15 diagram) Jumper the wheel pressure switch in the unit control center. Set the Timer Scale for T1 and T2 to 1 minute. Set the Timer Settings for T1 and T2 to 1.0. Set the dip switch to the down position. (normal position) Frost Threshold Temperatures Indoor RH at 70 F Frost Threshold Temperature 20% -10º F 30% -5º F 40% 0º F T2 Timer Scale T MIN T2 1 MIN T A2 Timer Dip Switch Turn the temperature sensor up as high as possible. The supply blower should cycle on for one minute, then turn off for one minute. After testing, set the Timer Scale as follows: T1 = 10 minutes, T2 = 1 hour Set the Timer Settings as follows: T1 = 0.5, T2 = 0.5. The timer is now set for 5 minutes off and 30 minutes on. Remember to remove the jumper. Electric preheat frost control includes an electric heater (at outdoor air intake) and an airflow pressure switch (located at the preheater) in addition to the thermostat and pressure sensor on wheel. (Refer to Electric Heater Application/Operation for electric preheater location). When electric preheat frost control is initiated, the electric preheater will turn on and warm the air entering the energy wheel to avoid frosting. Use the following test procedure for troubleshooting. Testing Turn the thermostat as high as it will go and jumper the wheel pressure sensor. The heater should turn on. If it doesn t, either put the outdoor airside doors on or temporarily jumper the airflow pressure switch in the preheater control center to avoid nuisance tripping of the pressure switch. Also check the airflow switch pressure tap located at the supply discharge blower to ensure the tubing is connected and the tap is not blocked. Remember to remove the jumpers. Modulating wheel frost control includes a variable frequency drive in addition to the thermostat and pressure sensor. When modulating wheel frost control is initiated, the variable frequency drive will reduce the speed of the wheel. Reducing the speed of the energy wheel reduces its effectiveness, which keeps the exhaust air condition from reaching saturation, thus, eliminating condensation and frosting. If the outdoor air temperature is greater than the frost threshold temperature OR the pressure differential is less than the set point, the wheel will run at full speed. If the outdoor air temperature is less than the frost threshold temperature AND the pressure differential is greater than the set point, the wheel will run at reduced speed until the pressure differential falls below the set point. The temperature and pressure differential set points are set at the factory, but are field-adjustable (refer to VFD section for more information). The variable frequency drive will be fully programmed at the factory. 24 Model RT Energy Recovery Unit

25 Economizer Application / Operation The energy wheel operation can be altered to take advantage of economizer operation (free cooling). Two modes are available: 1) De-energizing the wheel or 2) Modulating the wheel. A field supplied call for cool (Y1) is required. De-energizing the wheel is accomplished with a signal from a Temperature or Enthalpy sensor mounted in the air intake compartment. This Primary sensor will de-energize the energy wheel when the outdoor air temperature (factory default is 65ºF) or enthalpy (factory default is the D setting) is below the field adjustable set point. An Override temperature sensor is also furnished in the outdoor air intake compartment to deactivate economizer mode. The Override (with field adjustable set point) is set at some temperature lower than the Primary sensor (factory default is 50ºF). Effectively, the two sensors create a deadband where the energy recovery wheel will not operate and free cooling from outside can be brought into the building unconditioned. Testing Temperature Sensor with Override Turn both Temperature and Override thermostats down as low as they go. The wheel should be rotating. Turn the Temperature sensor up as high as it goes, and keep the Override sensor as low as it will go. The wheel should stop rotating. Temperature Sensor with Override Turn both sensors as high as they will go. The wheel should start rotating. Set the Temperature sensor at desired point for economizer operation to begin. Set the Override sensor at desired point for economizer operation to end (factory default is 65ºF and 50ºF, respectively). Enthalpy Sensor with Override Turn unit power off. Disconnect C7400 solid state enthalpy sensor from terminal So on the enthalpy controller. Also, disconnect the 620 ohm resistor from terminal Sr on the enthalpy controller. Turn unit power on. The LED on the enthalpy controller should light and the energy recovery wheel should not rotate. Turn unit power off. Reconnect 620 ohm resistor to terminal Sr on the enthalpy controller. Turn unit power on. The LED on the enthalpy controller should not light and the energy recovery wheel should energize and rotate. If the steps above provide the results described, the enthalpy economizer is working properly. Turn unit power off. Reconnect C7400 solid state enthalpy sensor to terminal So. Modulating the Wheel In applications in which an internal heat gain is present in the space, the rotational speed of the energy wheel may be modulated (via variable frequency drive) to avoid overheating the space during the winter. The speed of the energy wheel will be controlled in response to the discharge temperature set point. Sequence of Operation: The variable frequency drive is fully programmed at the factory (refer to VFD section for more information). A call for cool must be field wired to the unit (terminals provided Enthalpy Sensor with Override Enthalpy Controller in unit - refer to wiring diagram in unit control center) to allow for initiation of economizer mode. When the space calls for cooling, factory supplied controls will drive the following wheel operations: T AO > T RA T AO < T RA and T AO > T SA T AO < T RA and T AO < T SA Wheel runs at full speed. (maximum energy recovery) Wheel is stopped. (no energy recovery) Wheel will modulate to maintain discharge temperature. Where (T OA ) is the outdoor air temperature set point, (T RA ) is the return air temperature set point, and (T SA ) is the supply air discharge thermostat set point. Model RT Energy Recovery Unit 25

26 Variable Frequency Drives (VFD) An optional VFD may be installed at the factory for purposes of controlling the speed of the energy wheel or the blower motors. Its purpose is to constantly regulate the speed of rotation of the energy wheel or the blower motors in response to various optional sensors. Depending on the options selected by the owner, as many as three VFD s may be installed in the unit. When the VFD receives a predetermined signal, it will adjust the frequency (hertz) of the AC power supply to any connected motor, thus changing the speed of rotation. Typical Variable Frequency Drive (VFD) (refer to unit-specific documentation) The VFD is preset at the factory to respond to conditions specified by the owner. In some cases, the VFD will be controlled by owner-installed sensors and controlling devices such as CO 2 sensors, dehumidistats or pressure sensors. The VFD is sometimes an element of the frost control process for the energy wheel. Refer to the VFD manufacturer s information supplied with the unit and also see the unit-specific wiring diagram provided with the unit. A copy of the VFD manufacturer s manual can be found online at com. For technical support for the VFD, contact Yaskawa direct at Model RT Energy Recovery Unit

27 Remote Control Panel and Wiring Schematics The remote panel is a series of junction boxes ganged together and includes a stainless steel faceplate. The remote panel is available with a number of different alarm lights and switches to control the unit. The remote panel ships loose and requires mounting and wiring in the field The remote panel is available with the following options: Unit on/off switch Unit on/off light 7-day time clock Hand/off/auto switch Dirty filter light Economizer light Frost control light Wheel rotation sensor light Refer to Electrical Connections section for Field Control Wiring recommendations. Indicator Lights powered by the ER Unit R C G Unit On/Off Y1 Y2 W Frost Control Economizer Rotation Sensor NC PS2 C NO Dirty Filter PS3 NC C NO Dirty Filter Indicator (power by others) 7-Day Timer or On/Off Switch 7-Day Timer S1 - Unit On/Off R C G Terminal Block in Unit Control Center For 7-Day Timer, use blue and black wires. Red wires should be capped off. Hand/Off/Auto Switch Refer to Pressure Switch for voltage and load ratings. Heating/Cooling Switches and Night Setback Switch/Timer R C S1 Unit On/Off G On Off Auto BMS R C G Terminal Block in unit Control Center S6 S7 S4 Econ/First Stage Cooling Second Stage Cooling Y1 Y2 W1 6 7 Terminal Block in unit Control Center 12 Hand/Off/Auto Switch allows the unit to Off - off On - Manual Operation Auto - Unit is controlled by BMS, RTU, etc. NOTE: RTU controllers are by others. S5 Night Setback Timer Night Setback Switch A Model RT Energy Recovery Unit 27

28 Rotation Sensor The rotation sensor monitors energy wheel rotation. If the wheel should stop rotating, the sensor will close a set of contacts in the unit control center. Field wiring of a light (or other alarm) between terminals R & 12 in the unit control center will notify maintenance personnel when a failure has occurred (refer to Remote Panel Wiring Schematics section for wiring details). Dirty Filter Sensor Dirty filter sensors monitor pressure drop across the outdoor air filters, exhaust air filters, or both. If the pressure drop across the filters exceeds the set point, the sensor will close a set of contacts in the unit control center. Field wiring of a light (or other alarm) to these contacts will notify maintenance personnel when filters need to be replaced. The switch has not been set at the factory due to external system losses that will affect the switch. This switch will need minor field adjustments after the unit has been installed with all ductwork complete. The dirty filter switch is mounted in the exhaust inlet compartment next to the unit control center or in unit control center. Setscrew (on front of switch) must be manually adjusted after the system is in operation. Negative pressure connection is toward the front or top of the switch. (senses pressure on the blower side of filters) Microprocessor (DDC) Temperature Control Package The RT may be controlled either by owner-supplied and installed controlling devices or it may be optionally equipped with a microprocessor (DDC) control package. The DDC control package allows for stand-alone operation of energy recovery units. It permits integration of owner-supplied devices such as room thermostats, dehumidistats or CO 2 sensors. The controller regulates the temperature of air discharged from the unit. It can work in response to either temperature sensors in the discharged air (discharge control) or it will respond to room temperature sensors (room control). Typical DDC Controller (refer to unit-specific documentation) Room control requires a temperature sensor or room thermostat that will call for either heating or cooling to be wired to the controller. Room thermostats may be supplied by the owner or may optionally be provided by FHP. Positive pressure connection is toward the back or bottom of the switch. (senses pressure at air inlet side of filters) To adjust the switch, the unit must be running with all of the access doors in place, except for the compartment where the switch is located (exhaust intake compartment). The adjusting screw is located on the top of the switch. Open the filter compartment and place a sheet of plastic or cardboard over 50% of the filter media. Replace the filter compartment door. Check to see if there is power at the alert signal leads (refer to electrical diagram). Whether there is power or not, turn the adjustment screw on the dirty filter gauge (clockwise if you did not have power, counterclockwise if you did have power) until the power comes on or just before the power goes off. Open the filter compartment and remove the obstructing material. Replace the door and check to make sure that you do not have power at the alert signal leads. The unit is now ready for operation. 28 Model RT Energy Recovery Unit

29 Sensors Mounted by Factory Factory mounted temperature, pressure, and current sensors are available in the locations indicated on the unit diagram below. A list of available sensors is shown below. The specific sensors provided on a given unit are labeled in the unit control center on the terminal strip. Sensors are wired to the terminal strip to make it easy for the controls contractor to connect the Building Management System for monitoring purposes. EW-P RAF-P EF-A EAW RAI TO OUTSIDE RA FILTER FROM INSIDE EXHAUST BLOWER OAF-P OAI ENERGY WHEEL OAAW OAF-A FROM OUSTIDE OA FILTER COOL COIL HEAT COIL TO INSIDE SUPPLY BLOWER ACC OAD OAW-P Temperature Sensors - 1K Ohm RTD Drawing Labels Terminal Strip Labels OAI OAAW ACC OAD EAW OA/Supply Inlet Temp OA After Wheel After Cooling Coil Temp Supply Discharge Temp Exhaust After Wheel Temp RAI RA/Exhaust Inlet Temp Pressure Sensors (analog or digital) Drawing Labels Terminal Strip Labels OAF-P OAW-P RAF-P OA/Supply Filter Pressure Outdoor Air Wheel Pressure RA/Exhaust Filter Pressure EW-P Exhaust Wheel Pressure Amp - Current Sensors (analog or digital) Drawing Labels Terminal Strip Labels OAF-A EF-A Supply Fan Amps Exhaust Fan Amps Model RT Energy Recovery Unit 29

30 Optional Field-Installed Control Sensors The following sensors and control devices are all options that may be ordered with the RT. They are shipped loose with the unit and are to be fieldinstalled in a location selected by the A / E or the owner. Each device is to be installed in accordance with the manufacturer s instructions that are shipped with the unit. In all cases, retain the additional instructions for future use by the owner. CO2 Sensor The CO2 Sensor is an optional device provided by the factory. It may be factory-installed in the unit Return Air intake or it may require field installation in a duct or in a room. It has a number of different wiring options but is usually connected to the Variable Frequency Drive that controls the Supply Air blower. See also the unit-specific wiring diagram and installation instructions provided by the manufacturer. Typical CO2 Sensors Microprocessor (DDC) Remote Interface The optional Remote Interface Panel permits viewing of settings that are present on the microprocessor controller (DDC) and also permits inputting of new settings. It is to be field installed and is connected to terminal J10 of the Microprocessor Controller. See also the unit-specific wiring diagram and the Installation and Operating instructions provided with the remote panel. Typical DDC Remote Interface Remote Panel The optional Remote Panel may be used instead of a Microprocessor Controller (DDC). It has a number of different options that include manual or timed control of the unit and several different alarm indicators that are connected to sensors built into the unit. See also the unit-specific wiring diagram. Room Mount Duct Mount Dehumidistat The optional Dehumidistat is a passive device, requiring no supply voltage. It works in a make/ break manner. It can be installed in either a vertical or a horizontal position and the two wires found on the back of the sensor are to be connected to terminals B5 and BC5 on the Microprocessor Controller. See also unit-specific wiring diagram. Typical Remote Panels Room Temperature Sensor The optional Room Temperature Sensor is a simple thermistor-type sensor that provides an analog signal to the microprocessor controller (DDC) and is to be wired directly to terminals B4 and BC4 of the controller. Typical Dehumidistat Typical Room Temperature Sensor 30 Model RT Energy Recovery Unit