PACKAGED LIQUID CHILLERS

Transcription

1 C-Series PACKAGED LIQUID CHILLERS Service Manual INSTALLATION AND OPERATING INSTRUCTIONS Chiller Solutions LLC 1 Service Manual

2 Section 1.0 Receiving & Inspection...4 Section 2.0 Installation Basic Description Operational Clearance Service Access Clearance Additional Placement Considerations Outdoor Installation Indoor Installation (if ducting exhaust air is required) Mounting Plumbing Piping the Chiller Material Location Field Piping Design and Layout Insulation Power Supply to Chiller Electrical Connection Main Power Connection Grounding Voltage/ Phase/ Hertz Phasing Rotation Control Wiring Options Pumping System Pump Design Understanding the Properties of Anti-freeze Integrated Pumping Variable Speed System Pump (optional) AB Series Bypass Pump (optional) Chiller Liquid Charge...18 Section 3.0 Operation and Control of Edwards Packaged Chillers...19 Typical Electrical Component Layout (Standard) Water Temperature Control (Operating Control) High Pressure Control (Compressor Discharge Pressure) Pressure Control Adjustment Pressure Control Diagram Oil Pressure Safety Control (Compressor Lubrication) Freeze-Up Protection Control Fan Motor Pressure Staging Control Outdoor Units Only Compressor ON/OFF Switch System Circulator ON/OFF Switch By-pass Circulator ON/OFF Switch Motor Circuit Protection Gauge Panel...29 Section 4.0 Start-Up Procedure Initial Start-up and Start-up After Prolonged Shut down...31 Chiller Solutions LLC 2 Service Manual

3 Section 5.0 Functional Operation of the Refrigeration System Solenoid Valve Liquid Line Filter Drier Refrigerant Sight Glass and Moisture Indicator Thermostatic Expansion Valve (TXV) Superheat Adjustment Servicing Operational Function of the System...35 Air Cooled Chiller Refrigerant and Cooling Cycle Coolant System Pressure Relief Valve Automatic Air Eliminator / Tank Fill Pipe and Dip Tube Storage Tank Sight Glass Design and Application of the Edwards Packaged Chiller Pumping Application Operating Temperature Ranges...38 Appendix A - Temperature Control Settings...39 Chiller Indoor Installation...39 Chiller - Outdoor Installation...41 Appendix B Refrigeration Gas Conversion Charts...42 Appendix C - Troubleshooting Guide...43 Appendix D - Refrigeration Piping Assembly Standards...46 System Cleanliness...46 Pressure Testing of Piping...46 Evacuation and Dehydration...47 Brazing Techniques...47 Protective atmosphere...47 Flux...47 Clean Joints...48 Appendix E - Factory Functional Test Record...49 Appendix F Warranty...50 Chiller Solutions LLC 3 Service Manual

4 Section 1.0 Receiving & Inspection Visually inspect for any damage that might have occurred during shipping or transit. Note that your rights of damage claim are limited once the bill of lading has been signed. All freight leaving Chiller Solutions is FOB Pompton Plains, NJ (Please see the Chiller Solutions standard terms and condition of sale along with the Chiller Solutions Acknowledgement of shipping risk of loss forms for more details.) The purchaser above has submitted an order for original equipment products (hereinafter, products ) manufactured by Chiller Solutions LLC (hereinafter Seller ) of 101 Alexander Ave., Unit 3, Pompton Plains, NJ Notwithstanding any other agreed on Terms and Conditions of Sale/Purchase by and between the Purchaser and the seller, Purchaser shall make no claims against the Seller for loss upon shipment as a result of the products transportation, handling, storage, which is f.o.b. point of origin- generally, Pompton Plains, New Jersey, United States of America. Form CSL-16 Note: Damage occurring in transit may include concealed damage. All damages due to travel related abuse are not covered under the Chiller Solutions Standard Warranty. See Standard Warranty for details. Please check the following: 1. Visually inspect the unit and container for any signs of damage or abuse. 2. Remove all packaging from the unit and inspect for damage. 3. Open the electrical access door on the front of the unit and inspect for damage. 4. Open the compressor access door on the rear of the unit and inspect for damage. 5. Inspect the refrigerant pressure gauges (if provided) for pressure between 75 and 125 PSI on all gauges. (If gauges are not provided, a certified technician should check to ensure system pressure(s) are within the above limits.) Chiller Solutions LLC 4 Service Manual

5 Section 2.0 Installation 2.1 Basic Description The A series chillers are one of the most space efficient air cooled chillers available in the market. For a successful installation of the packaged chiller, attention must be given to the clearance allowed around the chiller. The chiller requires coolant fluid to remove heat, electrical power to drive the motors and controls, and air to reject heat. Appropriate clearance around the unit will allow the chiller to draw air through the condenser coils where the heat of absorption and other mechanical heat is rejected. After the heat is added to the air the fan system discharges the air away from the condenser coils. 2.2 Operational Clearance Operationally, the air condensers must be provided an unrestricted source of clean air. Outdoor installations require locating the system away from potential restrictions so that air can move unobstructed through the condensers. Ensure that at least 36 of space is allowed from each of the condenser coils to the nearest possible obstruction. Ensure that the discharge of the condenser fan system is unimpeded and that no obstructions can deflect airflow back toward the air cooled condenser coils. (See Section 2.4.2) WARNING! Restricting airflow to the inlet(s) or from the outlet(s) of the condenser section will restrict the ability to reject heat. This will lead to higher discharge pressures, higher power consumption, diminished chilling capacity, and premature failure of system components. Chiller Solutions LLC 5 Service Manual

6 2.3 Service Access Clearance Another important consideration for the placement of the A-series chiller is the ability to service the components. The A-series is designed to make access to each of the components simple with the removal of one of the access panels. Care must be taken not to obstruct access to these panels when piping or electrically connecting the system. Take special care not to restrict access to the front of the system to allow appropriate access to the operating and safety controls, and compressor area for servicing. Provide enough room on all sides of the unit for servicing and removal of the largest component, should replacement be necessary. Each access panel should have at least 36 of clearance to allow proper service/maintenance of the chiller. Consult local codes for additional clearance limitations. It is also necessary to review the operating environment of the chiller for anything that could affect the performance or longevity of the chiller. Items may include exhaust vents, additional cooling items, corrosive air environments, etc. Recommended distance of at least 36 from nearest object Chiller Solutions LLC 6 Service Manual

7 2.4 Additional Placement Considerations The environment the chiller is placed in will directly affect the performance of the system. Thoroughly understand the products limited warranty! Outdoor Installation In many metropolitan areas, fumes from vehicle exhaust may create an acidic condition in the air, which will prematurely corrode the components of the system. In some marine environments, salt will also prematurely corrode the components of the system. Some industrial buildings have exhaust vents which can increase the temperature of the air in an area causing a higher temperature air to enter the condenser. Debris from lawn maintenance or a naturally dusty environment can cause blockage in the air coils. While every environment can not be mentioned, care must be taken to ensure that the proper options are selected for a given installation, and that a suitable maintenance program is implemented Indoor Installation (if ducting exhaust air is required) Most of Edwards air cooled condensers are furnished with prop-type fans designed for open-air discharge, without ducts. Air requirements are 600 CFM per ton at nominal rating of unit. If ducts are to be connected for condenser air discharge, care should be exercised when designing ducts to ensure that the pressure drop does not exceed 0.1". Venting of the chiller should be planned and constructed so that no air restrictions occur because of duct size or type of installation. Ducts should be smooth on the inside, as rough places tend to collect debris which will decrease capacity and eventually clog the duct and prevent the chiller from exhausting condenser air. Elbows, if used, must be smooth on the inside. All joints must be made so that the exhausted end of one section is inside the next one down stream. Whenever an elbow is used, turning vanes should be utilized to control air stream. If duct work is not implemented at site location or deemed unnecessary, be sure that there are no obstructions, such as a roof or ceiling, above the path of the discharged air. If an obstruction is present, the hot air will not dissipate adequately and may return to the condenser coils and decrease the efficiency of the system. Chiller Solutions LLC 7 Service Manual

8 2.5 Mounting The chiller should be installed on a concrete pad or floor or reinforced floor capable of supporting the operating weight of the entire unit. (Refer to manufacturer s data for unit operating weight.) Consult local codes for additional structural requirements or limitations. Where seismic or vibration isolation is desired, use only isolation devices capable of supporting each corner of the machine according to the corner weight. Minimum distances should be maintained around the unit to allow for adequate air flow. Each chiller skid is designed to support the entire weight of the chiller through the base frame. Adequate support for the base frame is to be provided while moving and mounting the chiller. Moving or mounting a packaged chiller is hazardous and should only be attempted by experienced rigging professionals. CAUTION! Be sure to jack up the chiller evenly on all sides to avoid tipping the chiller over. Do not tilt the chiller more than 20 from its own vertical axis while installing. Do not leave chiller standing in an elevated position. Where casters are optionally provided, ensure that the casters are locked and sufficiently blocked prior to operation. Also ensure that these chillers are installed on a level surface. 2.6 Plumbing On air-cooled models, the only plumbing required is that of connecting the water inlet and outlet from the chiller to the equipment intended to use the chilled liquid solution. These connections should be made prior to the addition of liquid to the chiller. If subject to freezing conditions, use an anti-freeze solution Piping the Chiller Piping to and from the chiller should conform to standard industry practices which fall in line with all pertinent codes. Some considerations about piping the system are material, size, layout, and serviceability. When piping, take care to avoid obstructing the access panel below the piping and the air coil above the piping. Some anti-freeze solutions may not be suitable for use with certain joint compounds or piping products. Consult the manufacturer s information for confirmation prior to piping Material Many options such as PVC, steel, copper, stainless steel, etc. may be used to pipe the system. Examine the area of installation to determine the best solution. The material should be selected to operate in the environment, with the selected anti-freeze, at the chilled fluid temperatures, using joining techniques approved by the manufacture of said material. Material should also conform to all pertinent codes. Chiller Solutions LLC 8 Service Manual

9 2.6.3 Location The location of the chiller should partly be determined by the distance and complexity of the piping system. Distance and turns in piping increase the pressure drop of the system directly increasing the amount of energy required for pumping. Minimizing these factors will improve the efficiency of the chiller system. Location should also conform to all pertinent codes Field Piping Design and Layout A well designed piping system will provide a more reliable and efficient chiller system. Ensure design of piping meets all pertinent codes. Use material that is not affected negatively with the heat transfer fluid to be used. Size the piping large enough to ensure an appropriate velocity through the pipe. Cut down on pressure drop by using as few turns between the chiller and the process as practical. Support the piping according to all applicable codes or standard industry practices. Use air eliminators at the highest areas of the piping system. Use ball or butterfly valves near the inlet and outlet of the chiller to allow isolation from the rest of the system. Provide vibration dampening devices where necessary. Install a serviceable 60 to 80 mesh screen strainer in the return line of the chiller to prevent clogging of the evaporator. Provide a convenient fill valve for the system and an appropriately sized expansion tank. Note: When connecting the supply and return lines from the equipment to the chiller inlet and outlet, be sure to use a suitable flexible connector. Do not connect metal to metal to avoid any possibility of sound transmission from running equipment and other connecting equipment. POTABLE WATER MAXIMUM PRESSURE If liquids other than water (such as glycol, oils, etc.) are used in a chiller system, do not connect permanently to potable water supply If system is to be filled from city water supply, feed through a 25 PSI pressure reducing valve into the return line. Once system is filled, remove pressure reducing valve and feed line. The chiller storage tank is designed for a maximum pressure indicated on the relief valve. Chiller Solutions LLC 9 Service Manual

10 2.6.5 Insulation Insulating the piping is important to prevent condensation from forming on the pipes as well as absorbing heat from the surrounding area. The insulation should meet local codes, and conform to standard industry practice. The insulation should provide reliable thermal resistance and a vapor barrier. The thickness and type of insulation to be used depends on the temperature of the coolant fluid in the system along with the installation environment. 2.7 Power Supply to Chiller A circuit breaker or disconnect switch should be installed, in sight of the chiller, in the power supply lines. On units ordered with disconnect assembly factory mounted, no further devices are needed. The power lines should be connected to the main power tie in lugs as per the schematic diagram supplied with each unit. Factory Installed Disconnect Assembly The machine should be properly grounded and the wire supplying current to the chiller should be heavy enough to handle the chiller load without voltage drop in the line under full load. All wiring should be installed in accordance with local and national electrical codes. Main Electrical Connection (Section 2.7.2) Electrical Connection The A-series packaged chiller is engineered for single point electrical connection. All copper conductors should be used when connecting the electrical to the chiller. Electrical connection to the chiller should meet current National Electric Code along with local codes. The A-series chiller meets or exceeds NEC but may not conform to local codes. Consult local codes for details. Chiller Solutions LLC 10 Service Manual

11 2.7.2 Main Power Connection From the exterior of the chiller, electrical service connection holes have been provided into the main electrical panel. A chase nipple should be used from the exterior panel to the interior electrical box for adequate protection. The main power should connect directly to the top of the panel mounted disconnect marked L1 through L3. Failure to provide the correct electrical conductors and wiring could result in component failure and fire. WARNING! Failure to follow the prescribed Main Power Connection instructions could result in injury or death Grounding An appropriately sized ground must be secured to the Main Ground Lug provided adjacent to the panel mounted disconnect. Ensure that each electrical connection has torque sufficient to resist vibration related loosening. Grounding the chiller should meet current National Electric code along with local codes. See Illustration 4A for details Main Ground Lug Optional Voltage Phase Monitor Panel Mounted Disconnect (Factory Installed) WARNING!! Failure to follow the prescribed Grounding instructions may result in erratic operation of the motors and controls of the system or the premature failure of components. Unsafe operation of the system could result in injury or death Voltage/ Phase/ Hertz The A-series chiller is offered in multiple main power configurations. Ensure that name plate voltage/ phase/ hertz match the electrical service being provided to the system. WARNING! Failure to provide the correct main power configuration to the system may result in severe damage to the system. Chiller Solutions LLC 11 Service Manual

12 2.7.5 Phasing Rotation The A-series chiller typically utilizes a 3 phase system. Incorrect phasing will result in the motors of the system operating in reverse. Chillers utilizing the scroll style compressors are direction sensitive. Running these scrolls in reverse may result in permanent damage to the compressor. Ensure that prior to operating the chiller that other motors in the system are operating in the correct direction prior to starting the compressor. Please also review Section 4 and follow the start up check list. Incorrect phasing can typically be remedied by switching two of the main power legs on the line side of the main power disconnect. WARNING! Phasing the system should only be attempted by a qualified electrician as severe injury or death could result. WARNING! Operating the system in reverse rotation will result in the failure of the components of the system. Chiller Solutions LLC 12 Service Manual

13 2.7.6 Control Wiring Options The standard A-series is configured to allow simple remote operation of the chiller. The control terminal strip provides contacts to operate the chiller run, the pump run, and an alarm contact. Simply provide a normally open relay or switch to these contacts and close the contacts to operate. Consult the wiring diagram for the model of chiller purchased to verify the terminal numbers. These terminals have a factory jumper installed that would be removed if these remote starting options are implemented. You may also optionally purchase switches and/or a remote operating panel in several different configurations from Chiller Solutions. (Consult factory for options and accessories list) Pump Run Contacts - must always be closed and operating prior to the compressor. A system pump interlock in the compressor control circuit prevents the compressor from operating until the system pump starter is activated and operating. The Chiller Run contacts, when remotely connected, should close within a few minutes of starting the system pump or could be started simultaneously. Chiller Run Contacts - must be closed for the compressor to begin cooling. Alarm Contacts - will close with suction or discharge pressure safety control lockout. These dry contacts can be connected to many different controls to provide the operator information that the safety lockout has occurred. The contacts are rated for 240 volts at 10 amps. Flow Switch Contacts - are provided for simple attachment of a coolant flow switch as an option for factory installation or for field attachment. If opened (no flow), these contacts will disable the compressor circuit from operating. Chiller Solutions LLC 13 Service Manual

14 2.8 Pumping Pump design is commonly disregarded in overall system design. Most chillers will provide a pump that will accomplish the task of moving the volume of fluid at a given pressure. However, pump efficiency and design can add significantly to the operating and maintenance cost of the chiller system. An inefficient pumping system costs the operating process twice. First, an inefficient pump will require a larger horsepower motor to operate at the flow and pressure thus directly increasing the amount of power consumption. Second, an inefficient pump will add heat to the process that must be removed by the refrigeration process of the chiller. This is parasitic energy that has no benefit to the chiller operation System Pump Design Prior to purchasing the chiller, determine the total system flow and pressure drop to ensure that the correct pump is selected at the factory. Commonly, a process may require a higher or lower flow than the chiller is rated for. Once the flow and total dynamic head (TDH) is determined, simply select the appropriate pump for the application. If a specific pump is required that is not listed in the pump selection section, consult the factory for selection assistance Understanding the Properties of Anti-freeze Another consideration in pumping design is fluid viscosity and specific gravity. The addition of antifreeze to the system typically causes the fluid to become more viscous, or thicker, directly increasing pump energy requirements. When more anti-freeze is added than is required, the increase in viscosity results in parasitic energy consumption (mentioned previously). Additionally, antifreeze also adversely affects the specific heat of the fluid, or thermal conductivity. This impedance to heat transfer will degrade system efficiency thus increasing runtime and energy usage. Ensure that the appropriate amount of anti-freeze mixture is used to ensure optimal performance of the chiller system. Every 5% of concentration of glycol in the chilled system loop, the capacity of the system drops 1%. Refer to the chart for concentration according to the lowest ambient temperature conditions For example, a system with 60 40ºF: % Concentration of Pressure Drop Glycol (PSI) Pump HP Loss of Capacity % % % Chiller Solutions LLC 14 Service Manual

15 Gallons of Permanent Anti-freeze Required to Lower the Freezing Point of Water in the Storage Tank Only C-SERIES CHILLER MODEL NO. STORAGE TANK CAPACITY IN GALLONS TEMPERATURE +20 F +10 F 0 F -10 F -20 F -30 F -40 F PERCENTAGE ANTI-FREEZE BY VOLUME 17% 26% 35% 41% 45% 51% 53% Chiller Solutions LLC 15 Service Manual

16 2.8.3 Integrated Pumping The system pump is the primary pump for the chiller to move the coolant fluid to the process from the chiller. The standard configuration for the A-series is for the system pump to return the process coolant fluid back through the evaporator into the storage tank with the suction of the system pump connected to the bottom of the tank. This standard configuration requires that the system pump operate any time the refrigeration system operates. The A-series comes with a bypass circuit sized to allow enough coolant fluid flow to return to the evaporator for the safe operation of the refrigeration system. In applications where 2-way valves can effectively shut off all coolant fluid flow to or from the system, the chiller internal bypass valve must remain open or another method of bypass must be installed into the process piping. WARNING!! Compressor operation without rated coolant fluid flow through the evaporator could result in a freezing condition in the evaporator which could cause a freeze rupture. Closing the By-pass valve on a system that has no other means of by-pass could result in the loss of flow to the evaporator. Ensure that the compressor suction safety cutout device is appropriately calibrated to the chiller operating conditions along with the freeze point of the coolant. (See table # 6b for settings) WARNING!! Operating the system pump without a means of bypass in the system and the internal chiller bypass valve closed will result in pump failure Variable Speed System Pump (optional) Optional variable speed controls can be added to allow the system pump to maintain a pressure differential across the process with the use of a variable frequency drive and pressure transducer. This increases the efficiency of the system pumping part of the system by using only as much horsepower as is required to maintain a given pressure. As the AB-series chiller operates to maintain the tank temperature, the system pump can be independently controlled. Consult the factory for pricing and details. Chiller Solutions LLC 16 Service Manual

17 2.8.5 AB Series Bypass Pump (optional) In some applications a bypass pump is desired to maintain the chiller tank temperature, thus allowing the system pump to operate only with a call from the process or operator. This option changes the model name of the chiller to an AB-series. Maintaining the tank temperature provides a measure of thermal storage so that when the process calls coolant at set-point temperature is readily available. The bypass pump uses far less energy than the system pump due to the relatively small amount of pressure drop of the bypass circuit. Additionally, when the system pump is operating full time, the additional heat from pumping must also be chilled thus creating additional parasitic energy usage. Chiller Run with Bypass Pump In the system/bypass AB-series arrangement the C1 and C2 Chiller Run terminals, when closed, operate the bypass pump, which is interlocked with the compressor temperature control circuit. The chiller is sent with a Jumper between the chiller run terminals (C1 & C2), should exterior control be required, remove the jumper and field provide an isolation relay or switch (contact closure) to signal the chiller to operate. System Pump Run with Bypass Pump In the system/bypass AB-series arrangement the P1 and P2 System Pump Run terminals when closed operate the system pump independent of chiller operation. For the system pump to operate a field provided isolation relay or switch (contact closure) must be provided to the System Pump Run terminals (P1 & P2). Chiller Solutions LLC 17 Service Manual

18 2.8.6 Chiller Liquid Charge A fill pipe is located at the top of the storage tank of the water chiller and is so tagged (See Section 5.6 for illustration). By removing the cap from this line and inserting a funnel, the liquid to be chilled may be added to the storage tank and interconnecting lines. To allow for venting while filling the storage tank, make sure this funnel does not seal off the top of the fill pipe. Be sure to replace the cap and air vent after filling. On large installations, it may be desirable to pump the chiller liquid solution into the tank(s) and inter-connecting lines. Care should be taken in selecting the pump for this process. The storage tank(s) is designed for a maximum pressure indicated on the relief valve installed on the storage tank. A sight glass is located on each storage tank for a visual check on chiller liquid level. The storage tank is so designed to allow a 2" air cushion at the top of each tank for expansion of the chiller liquid when warm. POTABLE WATER If an anti-freeze solution is used in the chiller, do not permanently connect to potable water supply. AMBIENT FREEZING Chillers located outdoors should be protected for ambient freeze-up by anti-freeze solution to the lowest outside temperature likely to occur in the area where the chiller is to be installed. Chillers installed indoors should be protected by antifreeze solution to approximately 25 F below the lowest water temperature control setting to be used. Before starting chiller be sure controls are set in accordance with the control setting. Chiller Solutions LLC 18 Service Manual

19 Section 3.0 Operation and Control of Edwards Packaged Chillers The chiller is controlled automatically by the water temperature control located on the control panel (Section 3.1). Models 1 through 12 ton (Standard) The water temperature control senses the return chilled liquid to the chiller and cycles the compressor as the cooling load requires. It makes and breaks the electrical circuit to the compressor contactor upon reaching the cut-out setting on the control. The compressor will remain shut down until the return liquid to the chiller reaches the cut-in setting. This energizes the electrical circuit to the compressor and it will continue to operate until the cut-out temperature setting is again reached. Models 16 ton and larger (Standard) On these units the temperature control works in conjunction with the liquid line solenoid valve. When return chilled liquid reaches the cut-out setting, the temperature control breaks the electrical circuits to the liquid line solenoid valve allowing it to close. Once closed, the compressor goes into refrigerant pump down, pumping the refrigerant from the low side (evaporator) to the high side (condenser and receiver). As the refrigerant is pumped out of the low side, the suction pressure lowers until it reaches the cut-out point on the suction pressure control. The compressor will remain shut down until the return liquid to the chiller reaches the cut-in setting on the coolant temperature control. This will energize the electrical circuit to the solenoid valve and it will open allowing the suction pressure to rise. When the pressure reaches the cut-in point on the suction pressure control, it energizes the electrical control circuit to the compressor. Chiller Solutions LLC 19 Service Manual

20 Typical Electrical Component Layout (Standard) Section 3.1 Section 3.11 Section 3.5 Section 3.10 Section 3.2 Chiller Solutions LLC 20 Service Manual

21 3.1 Water Temperature Control (Operating Control) On single compressor units (1 though 60 ton) the standard temperature control is a single stage available in two temperature ranges: 20 F to 80 F and -30 F to 50 F. The control that corresponds best to the specified temperature range on chiller ordered will be used. Both controls are identical other than the difference in range. Each have an adjustable cut-in cut-out differential of between 4 and 14. This adjustment is found on the inside of the control. By removing the front cover, the adjustment slide on the right side can be moved up to increase, or down to decrease, differential. Additional control options are also available, please consult factory for pricing and specifications. On dual compressor models (60 through 120 ton units) a two stage temperature control is utilized with the same temperature ranges that are available in the single stage. The differential on the control is fixed at 3.5 F. The differential between the two stages is adjustable from 2 F to 7 F. Additional control options are also available, please consult factory for pricing and specifications. On units with three or more compressors, a multi-stage proportioning temperature controller is used. This unit incorporates a sensor, signal center, staging control, and potentiometer to provide accurate staging of the compressors under varying load conditions. OPTION: On units incorporating the 2 stage temperature control there is an option of a lead-lag compressor relay assembly. This will enable the operator to change the lead compressor which operates the first stage of the temperature control by a selector switch. The sensing bulb of the water temperature control is located in the return chilled liquid line of the chiller and is controlling the temperature of the chilled liquid. The front dial should be set at 5 F above the maximum temperature desired. The differential on the inside of the control should be set at the lowest temperature desired. This would be the setting on the front dial minus the differential. CAUTION! Before setting this control below 42 F, be sure to check the freezing point of the chilled solution with a hydrometer. The chilled solution should contain enough anti-freeze to protect it at 25 F below the minimum setting on the temperature control. Chiller Solutions LLC 21 Service Manual

22 3.2 High Pressure Control (Compressor Discharge Pressure) The pressure control senses the compressor discharge pressure. This control is required to be set no higher than 400 psi, and comes from the factory set at 375 psi. The high pressure control is tested for operation during factory testing. Once the control has tripped, the compressor will not start until the manual reset switch has been pressed. Be sure to check the troubleshooting guide for possible reasons for this safety control trip prior to reset of the device. Once the cause of the trip has been identified and remedied, reset of the switch will allow the compressor circuit to complete and the compressor to start. (Consult the electrical diagram for more information on impact of the high pressure control on the compressor circuit.) Models 1 though 12 ton (Standard) The control on this unit is a manual reset on both low and high pressure cut-out. The reset button is located on the front cover of the control and must be depressed to bring the unit back into operation after trip-out. The low pressure cut-out is to prevent freezing of the chilled solution on low suction. If the control trips on low pressure, check the settings on this control and the settings on the water temperature control. They should be in accordance with the charts in Appendix A. Frequent shutdowns on low suction usually indicate that the machine is low on refrigerant gas. The high pressure cut-out is set at the factory at 375 PSI. Models 16 tons and larger (Standard) The controls on these units are automatically reset by operation of the temperature control. Cut-in and cut-out points should be in accordance with the charts in Appendix A. Short cycling on low pressure control usually indicates that the control settings are incorrect or unit is low on refrigerant gas. The high pressure control is factory set at 375 PSI. Chiller Solutions LLC 22 Service Manual

23 3.2.1 Pressure Control Adjustment The following guidelines and diagrams illustrate the procedures for adjusting these controls. All-Range Controls (Low Side Only) The low side of All-Range pressure controls has a scaleplate that displays the CUT IN and CUT OUT setpoints. (See visible scale on left side of control.) Turning the range screw adjusts the CUT IN and CUT OUT setpoints up or down simultaneously, while maintaining a constant pressure differential. Turning the differential screw adjusts the CUT OUT setpoint only on the left side of the scale, and changes the pressure differential. High Side Dual Pressure Controls The high side of the dual pressure control has a scaleplate that displays only the CUT OUT setpoint. (See the visible scale on right side of control.) Turning the range screw adjusts the CUT OUT setpoint. The differential is fixed at approximately 65 psi. For controls with the high side (or combination low side and high side) Manual Reset Lockout option, see Manual Reset Operation. CAUTION! DO NOT ADJUST POINTERS BEYOND THE HIGHEST OR LOWEST INDICATOR MARKS ON THE CONTROL S PRESSURE SCALE. ADJUSTING POINTERS BEYOND INDICATOR MARKS MAY DAMAGE SCREW THREADS AND CAUSE INACCURATE CONTROL OPERATION. CAUTION! CAUTION! USE THE PRESSURE CONTROL SETTINGS RECOMMENDED BY THE MANUFACTURER. DO NOT EXCEED THE PRESSURE RATINGS OF THE CONTROLLED EQUIPMENT OR ANY OF ITS COMPONENTS WHEN CHECKING PRESSURE CONTROL OPERATION OR OPERATING THE CONTROLLED EQUIPMENT AFTER INSTALLING AND ADJUSTING PRESSURE CONTROL AND BEFORE LEAVING INSTALLATION, CYCLE THE CONTROLLED EQUIPMENT SEVERAL TIMES (AT LEAST THREE) AT NORMAL OPERATING CONDITIONS. USE PRESSURE GAUGES TO VERIFY PROPER CONTROL SETTINGS AND EQUIPMENT OPERATION Chiller Solutions LLC 23 Service Manual

24 To manually adjust the pressure controller, follow the steps below. 1. Set low side CUT IN by adjusting low side range screw. Turn screw clockwise to raise CUT IN setpoint. 2. Adjust the differential screw. Turning the differential screw changes the CUT OUT setpoint. Turn screw clockwise to raise CUT OUT setpoint. 3. Set high side CUT OUT setpoint by adjusting high side range screw. Turn screw clockwise to raise the CUT OUT setpoint. (High side differential setting is fixed.) Manual Reset Operation Pressure controls with the Manual Reset option lock out when they reach the CUT OUT pressure setpoint and must be manually reset by the user to restart the chiller system. The manual reset mechanism is trip-free and cannot be overridden by blocking or tying the reset button down. On equipment with locked out controls, first determine and remedy the cause of the lockout before proceeding. When lockout is caused by the control s low side CUT OUT, allow the sensed pressure to rise to the CUT IN setpoint. When lockout is caused by the control s high side CUT OUT, allow the sensed pressure to drop at least 70 psig below the CUT OUT setpoint. After the sensed pressure has reached the desired pressure (as described above), press and release the Reset button on the front of the control to restore operation of the chiller. Chiller Solutions LLC 24 Service Manual

25 3.2.2 Pressure Control Diagram Differential Screw (Low Side Only) Low Side Range Screw Manual Reset Button (Combination Low Side and High Side Manual Reset) High Side Range Screw Low Side CUT OUT or DIFFERENTIAL pointer Low Side Bellows High Side Bellows High Side CUT OUT Pointer Low Side CUT IN pointer Chiller Solutions LLC 25 Service Manual

26 3.3 Oil Pressure Safety Control (Compressor Lubrication) Models 30 ton and up (Standard) The two probes of this control are placed between the compressor lubrication oil pump and the compressor crankcase pressure and are sensing the pressure differential between these two points. This control is factory preset at 9 PSI differential and no field adjustment should be made. Should the compressor shut down on the oil pressure control, check the level of oil in the compressor oil sight glass located on the side of the compressor; oil should be approximately half way on the sight glass. IMPORTANT! 3.4 Freeze-Up Protection Control Never reset this control more than once. If compressor goes off on oil pressure control again, a refrigeration service organization should check out and correct this problem. At no time should this control be jumped out or set below the 9 PSI differential. If control is reset more than once, permanent damage may be cause to the compressor bearings due to lack of lubrication. Models 16 ton and up (Standard) This control prevents the freezing of the chilled liquid on low pressure. It incorporates a time delay network to allow momentary low pressure surge and low pressure build up during compressor start-up. This control must be manually reset by depressing the reset button located on the front cover. This control should be set in accordance with the control setting charts in Appendix A. 3.5 Fan Motor Pressure Staging Control Outdoor Units Only Models 3 and 5 ton The pressure transducer and a permanent split capacitor motor provide infinite speed variation of the condenser fan. The pressure connection of this control is made directly into the high pressure side of the chiller. The transducer sensing the high pressure variation, coupled with the builtin printed circuit, modulates the phase conduction angle of the bipolar AC sine wave power supply to the fan motor. Models 7 ton and up (Standard) These units use a multiple fan motor arrangement to provide increased or decreased air flow through the condenser under varying ambient conditions. Each fan controller has a pressure control with a cut-out for operation of the fan motors. These controls are preset Chiller Solutions LLC 26 Service Manual

27 at the factory at cut-in and cut-out points and are both automatically reset by the increase and decrease in condensing pressure. 3.6 Compressor ON/OFF Switch If present, this switch is used to make and break the electrical circuit to the compressor controller. It should be kept in the on position at all times of normal operation. On chillers 16 tons and larger, this switch should be used as an emergency shut down only. 3.7 System Circulator ON/OFF Switch If present, this switch operates the main system circulator. Control Circuit Voltage 115 Volts. 3.8 By-pass Circulator ON/OFF Switch If present, this switch operates the by-pass circulator controller. The by-pass pump should be kept in the on position at all times Positively do not run the compressor with the by-pass pump switch in the off position or freeze-up of the evaporator might occur. CAUTION! Chiller Solutions LLC 27 Service Manual

28 3.10 Motor Circuit Protection Motor protectors are supplied for each pump, compressor, and fan and are so labeled in ascending numerical order (See wiring diagram for motor protector assignments). Each motor protector is factory set for maximum operating conditions where condensing temperatures may reach as high as 140ºF and exercise additional amp draw on the component. To manually set protection level, insert a small flat-head screwdriver into the slot located on the dial left of the STOP indicator. Lineup indicator arrow to desired amp protection: counterclockwise to increase and clockwise to decrease. Care should be exercised when setting the dial outside factory recommendation. Note: Dial setting is full load motor current. Trip current is 125% of dial setting. Typical Protection Device Note Location of Dial WARNING! The opening of the branch-circuit protective device may be an indication that a fault current has been interrupted. To reduce the risk of fire or electric shock, the component of the controller should be examined and replaced if damaged. If burnout of the current element of an overload relay occurs, the complete device must be replaced. Chiller Solutions LLC 28 Service Manual

29 3.11 Gauge Panel When performing preventative maintenance, or servicing the chiller, the supply of accurate data is essential to troubleshoot and repair any known issues. The upper portion of this stainless steel panel includes one liquid filled pressure gauge for the suction line and one for the discharge. These gauges provide simple read-out of the operating refrigerant pressures. The 6 point temperature display is mounted to the front of the electrical enclosure. This electronic display utilizes a selector knob to display 1 of six temperatures. The temperatures sensed are: Fluid Inlet Temperature Fluid Outlet Temperature Suction Line Temperature Liquid Line Temperature Compressor Discharge Temperature Condenser Air Outlet Temperature The pressure-temperature (PT) chart is used by a technician to ensure proper system operation. PT charts are most often used for three purposes: to set a coil pressure so that the refrigerant produces the desired temperature, to check the amount of superheat above the saturated vapor condition at the outlet of the evaporator and to check the amount of sub-cooling below the saturated liquid condition at the end of the condenser. Chiller Solutions LLC 29 Service Manual

30 Section 4.0 Start-Up Procedure CAUTION! DO NOT TURN DISCONNECT SWITCH TO THE ON POSITION UNTIL THE FOLLOWING STEPS HAVE BEEN COMPLIED WITH. UNDERSTAND THE FOLLOWING STEPS BEFORE PROCEEDING WITH UNIT POWER-ON. 1. Ensure that system is completely filled with chiller liquid (water; water/glycol; etc.) 2. Close all gate valves going to the process to be cooled. 3. Turn all compressor and circulator on-off switches to the off position, if applicable. 4. AIR COOLED MODELS ONLY - Check fan blade clearance in venturi to ensure that proper clearance has been maintained and blades are clear. 5. Set all temperature and pressure controls in accordance with the control settings in Appendix A. 6. Open all gate valves on unit that pertain to the recirculation piping. 7. ALL SINGLE PUMP UNITS - Open the by-pass valve located above the circulator in the by-pass line. 8. Place the main power disconnect switch to the on position. 9. Turn the by-pass pump to the on position and check rotation. Rotation should be in accordance with the direction arrow shown on pump housing. If rotation is incorrect, shut off main power disconnect and interchange two of the three phase wires supplying power to the unit. 10. Unit is now ready for start-up. a. Turn disconnect switch to on position. b. Unit should be left in this position for 24 hours to allow time for compressor crankcase heater to boil off any refrigerant liquid that might be in crankcase. c. Turn by-pass pump to the on position. d. On model 16 tons and higher, turn manual pump-down switch to on position, if applicable. e. Turn compressor on-off switch to the on position and compressor will start if applicable. Note: Condenser fans will start modulating once head pressure exceeds 200 PSI. The pressure transducer located on the compressor discharge line provides a 4-20mA signal to a VFD which modulates fan RPM to maintain discharge pressure. Chiller Solutions LLC 30 Service Manual

31 4.1 Initial Start-up and Start-up After Prolonged Shut down If water temperature in storage tank and lines are high (above 75 F) upon start-up, the compressor may shut off on the high pressure control. This is normal; if it occurs, wait until suction and discharge pressures (as read on pressure gauges) read approximately within 5 PSI of each other, then reset the discharge control. This operation may have to be repeated until the water temperature in the tank reaches a lower temperature. Chiller Solutions LLC 31 Service Manual

32 5.0 Functional Operation of the Refrigeration System The Edwards Packaged Chiller has the major components found in all refrigeration systems: evaporator, compressor and condenser. In addition to these major components, the system also has a thermal expansion valve, suction tube, liquid suction interchanger, filter drier, suction line filter, vibration eliminators, receiver, low and high side charging valves. 5.1 Solenoid Valve The solenoid valve is an on/off type valve which operates when the energized solenoid coil uncovers a port inside the valve allowing it to open. The valve also is equipped with a manual stem allowing the valve to be closed using a refrigeration service wrench. This valve is designed to protect the system from liquid migrating in off cycle times. The solenoid is opened simultaneously with compressor operation. 5.2 Liquid Line Filter Drier The liquid line filter drier is a hermetically sealed type filter drier designed to assist in screening and dehydrating the liquid refrigerant returning from the condenser. The filter drier is installed prior to the solenoid valve, sight glass and expansion valve thus providing additional protection. 5.3 Refrigerant Sight Glass and Moisture Indicator The sight glass is designed with a moisture indicator to provide a view inside the liquid line. The moisture indicator changes color based on the amount of moisture in the system. 5.4 Thermostatic Expansion Valve (TXV) The expansion valve operates to control the amount of refrigerant that enters the evaporator. The valve is designed in three primary components: the body, the cage, and the power-head. The cage is designed to operate in a range of capacities and can be exchanged with other cage sizes within the design of the expansion valve assembly. The power-head is designed to monitor the suction line temperature and pressure providing control of the amount of superheat directly after the evaporator. Chiller Solutions LLC 32 Service Manual

33 5.4.1 Superheat Adjustment The superheat can be adjusted using a standard flat screwdriver to adjust the spring tension of the cage. This is located under the 9/16 hex bolt on the valve below the dome of the power-head. WARNING! ONLY A CERTIFIED REFRIGERATION TECHNICIAN SHOULD ATTEMPT TO ADJUST THE SUPERHEAT; VALVES ARE FACTORY-SET TO A SPECIFIC SUPERHEAT. IF ADJUSTMENT IS NEEDED REFER TO INSTRUCTIONS BELOW FOR PROPER PROCEDURE. IMPROPER ADJUSTMENT MAY RESULT IN VALVE MALFUNCTION AND/OR SYSTEM DAMAGE. Expansion valves are factory-set for a static superheat. However, the superheat can be adjusted if needed. To properly adjust Alco Thermo Valves to other superheat settings: 1. Remove seal cap on side of valve 2. Turn the adjusting stem in a clockwise direction to increase the super heat, and counter clockwise to decrease superheat (approximately 1/2ºF per turn for R22 applications). Allow adequate time between adjustments for system to stabilize before checking superheat. 3. When the desired superheat is achieved, reinstall the seal cap. Note the location of the 9/16 hex bolt to be removed to access the screw that will adjust spring tension Chiller Solutions LLC 33 Service Manual

34 5.4.2 Servicing Before opening any system, make sure the pressure in the system is brought to and remains at atmospheric pressure. Failure to comply may result in system damage and or personal injury. To inspect, clean, or replace parts of the Emerson Thermo valve: 1. Disconnect equalizer line. 2. Remove the cap screws. 3. Carefully lift off the power assembly. 4. Remove cage assembly and gaskets. 5. Lightly oil gasket with refrigeration oil. (Note: Good service practice replacing all gaskets whenever a valve is opened.) 6. Assemble in the same order as disassembled. 7. When putting the power assembly on, make sure the cage assembly lugs line up with the slots inside the power assembly. (See figure below) 8. Tighten cap screws evenly and torque to 300 inch pounds. 9. Check for leaks. Chiller Solutions LLC 34 Service Manual

35 5.5 Operational Function of the System The high pressure & temperature refrigerant vapor is pumped from the compressor discharge side to the condenser where removal of heat and condensation of the refrigerant from a vapor to a liquid occurs. The high temperature & pressure liquid then passes into the filter drier, this removes any moisture from the liquid refrigerant. After passing through the liquid drier, the liquid passes through the liquid line sight glass and into the thermal expansion valve. The thermal expansion valve senses the temperature in the suction line leaving the evaporator by a remote sensing bulb. The TXV meters the amount of refrigerant fed to the evaporator and in conjunction with the compressor, maintains a proper pressure differential between the high side and the low side of the system. Upon leaving the expansion valve, the liquid refrigerant is subjected to a much lower pressure and the refrigerant immediately begins to vaporize. As refrigerant passes through the evaporator it completely vaporizes, drawing heat from the surrounding evaporator surface and water passing through the evaporator coil. The low pressure & temperature vapor is then drawn back through the suction line. At the same time, the temperature of the water passing through the evaporator coils is lowered as a result of the heat being drawn from it. Chiller Solutions LLC 35 Service Manual

36 Air Cooled Chiller Refrigerant and Cooling Cycle Chiller Solutions LLC 36 Service Manual

37 5.6 Coolant System The three major components of the coolant system are the system circulator, by-pass circulator* and combination storage tank and evaporator. The coolant is pumped from the storage tank to the equipment to be cooled and returned by means of the system circulator. The returning coolant is then boosted by the operation of the by-pass circulator and fed into the evaporator coil inside the storage tank. Here heat is removed from the coolant by the refrigerant surrounding the evaporator coolant passages. After leaving the coils at the desired temperature the coolant is discharged into the storage tank where it is ready to be used to complete the coolant cycle. This system also incorporates a by-pass line with a swing check valve, which allows water to by-pass directly to the by-pass circulator when the system pump is pumping against a dead head or system pump flow is greatly reduced. This ensures that a proper flow is maintained through the evaporator and the refrigeration cycle is kept at top efficiency. The coolant system also incorporates several minor components: an automatic air eliminator, tank fill pipe and dip tube, a storage tank sight glass and a storage tank pressure relief valve. Chiller Solutions LLC 37 Service Manual