Product Data. Features/Benefits. 50BYN Single-Package Air Cooled Vertical Packaged Units. 5to20Tons

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1 Product Data 50BYN Single-Package Air Cooled Vertical Packaged Units 5to20Tons The 50BYN units are single-package cooling units with integral air-cooled condensers designed for indoor installations. They provide a practical and economical approach to comfort conditioning requirements for offices, factories, and other applications in existing buildings when indoor air-cooled condensers are required. Compact, durable, and attractive cabinet fits any working environment Ducted or free return with rear return connections with vertical or horizontal front supply air discharge High-efficiency cooling for commercial and industrial projects Rear condenser inlet and discharge and belt drive condenser fan permit condenser air connections to be ducted through window or wall louver Features/Benefits Design flexibility Carrier indoor package units are designed to provide the flexibility required in replacement, renovation, and new construction. Units are available in 6 sizes from 5 tons to 20 tons which meet the needs for cooling restaurants, retail stores, warehouses, offices, and building additions. The compact footprint and service from the front of the units save valuable floor space in equipment rooms. Belt drive condensers provide adequate static to overcome ducting and louver static losses. This allows units to be positioned against an existing window or wall louver, or ducted to the outside, as required. These units can be installed in the equipment room or the conditioned space and used for either ducted or free return applications. Convenient rear connections allow easy access for outside air connections and air side economizer. Unit supply air discharge may be vertical or horizontal front to make the best use of headroom. Copyright 1998 Carrier Corporation Form 50BY-1PD

2 Easy installation and maintenance The units are completely pre-piped and wired at the factory to ensure time and money saving installation and service. Exterior access panels are easily removed to provide speedy inspection and service work may be done from the front of the unit. Precision engineered parts translate to a quality built, reliable design that will operate efficiently, minimize service calls, and provide years or reliable operation. Designed for customer satisfaction Where space and styling are important considerations. Models 50BYN are designed to exceed expectations. The high quality baked enamel finish will fit any environment attractively. These packaged systems provide the user with economy and product satisfaction in cooling, heating (with accessory heating coil), dehumidification, filtering, and air circulation. All units are designed to fit through most standard doors. The 20 ton size may be easily field split to simplify moving the units into existing buildings. Special features for outstanding performance High efficiency Carrier scroll compressors deliver quiet, reliable cooling capacity. Compressor motor protection is assured by quick-acting, internal sensing elements that prevent trouble before it starts. Space-saver slab type evaporator and condenser coils use Carrier s advanced heat transfer technology and provide peak heat transfer efficiency with large coil face area. Fins are mechanically bonded to nonferrous, seamless tubing for efficient leakfree operation. Quiet fan performance large volumes of indoor air are moved quietly. Compact housing and specially designed discharge air section provide superior air handling capacity. Convenient front access electrical control center contains all factory prewired control devices. Utilizing a specially designed sloped condensate pan, water will not accumulate in the basepan, meeting the ASHRAE 62 (American Society of Heating, Refrigeration and Air Conditioning Engineers) indoor-air quality standards to provide a comfortable and safe occupied space. As a result of this new design, the coil is easily accessed for cleaning. The interior of the evaporator section is lined with a heavy gage aluminum liner, providing cleanable surfaces for optimum indoor air quality. The weather-resistant cabinets are The 10 to 15 ton units are 2 compressors each on independent cir- constructed of galvanized steel, bonderized, and coated on all external cuits. This provides backup protection and better part load operat- surfaces with a baked enamel finish. The paint finish is nonchalking and is ing efficiency. capable of withstanding ASTM The 20 ton unit uses 3 compressors, Standard No hour salt each on its own independent circuit. spray test. Standard wiring from the factory A choice of controls provides the flexibility to meet almost any applica- and 1 compressor on the second has 2 compressors on the first stage tion. Choose between a full line of stage. This can be easily changed at Carrier room-mounted thermostats, the jobsite to put 2 compressors or the Carrier TEMP System thermostat which provides for communiing 3 steps of control, for optimum on the second stage or even providcating control or interface to VVT part load operation. (variable volume and temperature) All motors are protected against singlephasing conditions. systems. Full compressor protection is assured Units are built in an ISO 9000 (International Standards Organization) certi- by several devices, including Cycle- LOC current-sensing lockout relay, fied manufacturing facility, and are Time Guard II anti-short cycle fully run-tested. In addition, all units control, and high- and low-pressurestats. have as standard the capability to These devices lock out the compressor under abnormal operating indicate a needed service. conditions to prevent compressor Evaporator fan on the 20 ton unit damage and ensure long life. easily removable to aid in rigging unit into existing buildings. Fan discharge on all sizes (except 014 size) The 50BYN units are fully warrantied as shipped from the factory, including can be quickly converted from vertical 1 year on all parts (compressor included). Additional 2 to 5 year to horizontal front supply. warranty on the compressor is standard on 5 to 15 ton units, and is vide a choice when installing the unit. Dual condensate drain locations pro- available as an option on the 20 ton The installer can use whichever unit. drain best suits the particular application, saving both installation time Easy to understand and operate controls provide a virtually mistake-proof drain provides protection against and expense. A built-in secondary control operation. a plugged primary drain or rain entering the condenser, and may elimi- Two-stage capacity control provides back-up protection, additional operating efficiency, and energy drain pan at the jobsite. nate the need to provide an additional savings. Table of contents Page Features/Benefits... 1,2 ARI Capacities... 3 Model Number Nomenclature... 3 Field-Installed Accessories... 3 Physical Data... 4 Base Unit Dimensions Selection Procedure... 8 Performance Data Electrical Data Typical Wiring Schematic Controls Typical Piping and Wiring Application Data Guide Specifications...25,26 2

3 Model number nomenclature ARI* capacities UNIT 50BYN NOMINAL TONS EVAPORATOR CFM CONDENSER CFM NET COOLING (Btuh) TOTAL kw EER/ SEER IPLV ,000 3,000 59, ,000 4,500 81, ,000 6, , ,800 7, , ,000 9, , ,000 12, , LEGEND EER Energy Efficiency Ratio IPLV Integrated Part Load Value SEER Seasonal Energy Efficiency Ratio *ARI Air Conditioning and Refrigeration Institute. SEER applies to 5 ton unit only. Field-installed accessories Heating coils Field installed coils for hot water or steam, with convenient field piping connections on side of unit. Coil mounts in front of cooling coil and uses unit return-air filter track. Thermostats A complete line of Carrier thermostats is available to meet any control requirements, including Carrier TEMP System thermostats for diagnostics and communicating capability. Low ambient damper Refrigerant pressure operated damper mounted on condenser air discharge modulates to control head pressure. Permits unit to operate in cooling even in winter, when outdoor air temperature is low. Damper automatically restricts condenser airflow to maintain correct condensing pressure for efficient operation at temperatures down to 0 F. Winter start kit This package provides a time delay for the low-pressure switch. Defrost thermostat kit This package allows the unit compressor to turn off when frost begins to form on the evaporator coil. Discharge plenum This kit is for use in free blow applications for controlled free blow into the conditioned space. Economizer mixing box This kit is for free cooling with or without Differential Enthalpy. CO2 sensor This kit is for Indoor-Air Quality Control when Economizer is used. 3

4 Physical data UNIT 50BYN NOMINAL CAPACITY (tons) UNIT OPERATING WEIGHT (lb) COMPRESSOR Carrier Scroll Model SR58 SR75 SR58 SR58/SR75 SR75 SR75 Quantity /1 2 3 Rpm 3500 Oil Charge (oz) /44 50/44 50/50 50/50/50 Steps of Control * OPERATING CHARGE R-22 (lb) / / / /9.9/9.9 EVAPORATOR FAN Adjustable, Belt-Driven, Centrifugal Nominal Cfm Cfm Range 1,500-2,500 2,250-3,750 3,000-5,000 3,750-6,250 4,500-7,500 6,000-10,000 Available Static Fan Size x x x x x x9 1 2 Number of Fans Standard Speed Range (Rpm) Max Allowable Rpm Motor Rpm 1725 Vertical Belt Quantity...Type 1...A A B B A B52 Horizontal Belt Quantity Type 1...A A B32 None 2...A B41 Fan Pulley (in.) Motor Pulley (in.) Nominal Hp...Frame Size T T T T T T Fan Shaft Size (mm) Motor Shaft Size (in.) Center Distance (in.) min/max Center Distance (in.) min/max.** N/A N/A EVAPORATOR COIL 3 8-in. OD, Enhanced Copper Tube, Aluminum Fins Quantity Rows - Fin/in Face Area (sq ft) RETURN AIR FILTERS 1 or 2 in. Disposable Type Quantity...Size x x x x x x x x x x 20 CONDENSER FAN Adjustable, Belt-Driven, Centrifugal Nominal Cfm ,000 Cfm Range 2,250-3,750 3,375-5,625 4,500-7,500 5,400-9,000 6,750-11,250 9,000-15,000 Available Static Fan Size 11x x x11 11x x x14 Number of Fans Standard Speed Range (Rpm) Max Allowable Rpm Motor Rpm 1725 Belt Quantity...Type 1...A B A A A B88 Fan Pulley (in.) Motor Pulley (in.) Nominal Hp...Frame Size T T T T T Fan Shaft Size (mm) Motor Shaft Size (in.) Center Distance (in.) min/max CONDENSER COIL 3 8-in. OD, Enhanced Copper Tube, Aluminum Fins Quantity Rows...Fins/in Face Area (sq ft) CONTROLS 24 Volts Provided in Unit High Pressure Cutout (psig) 395 Cut-in (psig) 300 Low Pressure Cutout (psig) 27 Cut-in (psig) 67 Fusible Plug 203 F Time Guard II Devices 5 Minutes on Each Circuit CONDENSATE DRAIN LINE 2@ 3 4BPS LEGEND NPT National Pipe Thread BPS British Pipe Standard (NPT pipe will work with the type of fitting) *The 20 ton unit is factory wired for 2 stages of capacity control. With the addition of a threestage thermostat or outdoor-air thermostat, the unit is capable of 3 stages of capacity control. Shaft center distances shown are for vertical discharge arrangement. **Shaft center distances shown are for horizontal discharge arrantement. 4

5 Base unit dimensions 50BYN DIM. 50BYN006 50BYN008 50BYN012 50BYN014 mm ft-in. mm ft-in. mm ft-in. mm ft-in. A B C D E F G H J K L M N P Q R S T V W X Y Z AA AB AC AD AE AF AG AH AJ AK AL AM AN AP AQ AR AS AT NOTES: 1. Dimensions in [ ] are in millimeters. 2. Center of gravity. 3. Direction of airflow. 4. One side of unit must have minimum of 3 [914] clearance for filter removal. CORNER WEIGHTS Dim. 50BYN006 50BYN008 50BYN012 50BYN014 kg lb kg lb kg lb kg lb A B C D

6 Base unit dimensions 50BYN016 NOTES: 1. Dimensions in [ ] are in millimeters. 2. Center of gravity. 3. Direction of airflow. 4. One side of unit must have minimum of 3 [914] clearance for filter removal. CORNER WEIGHTS Dim. 50BYN016 kg lb A B C D DIM. 50BYN016 mm ft-in. A B C D E F G H J K L M N P Q R S T V W X Y Z AA AB AC AD AE AF AG AH AJ AK AL AM AN AP AQ AR AS AT AV

7 Base unit dimensions 50BYN024 CORNER WEIGHTS Dim. 50BYN024 kg lb A B C D DIM. 50BYN024 mm ft-in. A B C D E F G H J K L M N P Q R S T V W X Y Z AA AB AC AD AE AF AG AH AJ AK AL AM AN AP AQ AR AS AT AV NOTES: 1. Dimensions in [ ] are in millimeters. 2. Center of gravity. 3. Direction of airflow. 4. One side of unit must have minimum of 3 [914] clearance for filter removal. 7

8 Selection procedure (with example) I Determine design conditions. Given: Cooling Requirements Total Cooling Capacity (TC)...87,000 Btuh Sensible Cooling Capacity (SHC)...70,000 Btuh Evaporator Air Quantity...3,000 Cfm Summer Entering-Air Conditions: Entering dry bulb (edb)...82f Entering wet bulb (ewb)...67f Entering Condenser Air Temp (EAT)...95F Unit Voltage...460V Heating Requirements Total Heating Load (TC)...200,000 Btuh Winter Entering-Air Temp (edb)...50f Entering Hot Water Temp (ewt)...200f Fan Requirements External Static Pressure Required ESP (in. wg) II Select unit based on cooling requirements. Enter Cooling Capacities table for unit at 3000 cfm and required wet bulb of 67 F and read down to the section displaying capacities with 95 F entering air temperature. The 50BYN008 provides a total capacity closest to design requirements. For out example: Unit selection 50BYN008 Selected at 3000 cfm of 82 F edb, 67 F ewb entering air. TC = 88,800 Btuh Corrected SHC = 66,100 Btuh + (1.45 x 3000 cfm) = 70,456 Btuh (See SHC Correction Table, following cooling capacity tables.) Compressor Power Input = 5.08 kw Leaving Air db 82 F (70,456/[1.1 x 3000 cfm]) = 60.6 F Leaving Air wb h at 67 F wb = (88,800 Btuh/[4.5 x 3000 cfm]) = wb at = 56.9 F III Determine heating capacity. Enter Accessory Heating Coil Capacities table, page 12, with selected air cfm. Select the desired water temperature drop and read data, then correct as indicated in heating correction tables. 200 F hot water selection: TC = 211,000 Btuh selected at 3000 cfm correction factor at of 50 F entering air is 1.08, then TC is 227,000 Btuh this will exceed the job requirements. Heating leaving air temperature 50 F + (227,000 Btuh/[1.1 x 3000 cfm]) = F Heating gpm 227,000 Btuh/(20 F x 500 ) = 22.7 gpm IV Fan requirements. External static pressure (ESP) required 0.75 in. wg Static pressure loss through heating coil 0.08 in. wg Total external static required 0.83 in. wg Enter Fan Performance tables, page 13 for cfm, and static pressure required to obtain the following data: For 3000 cfm and 0.83 ESP, by interpolation the fan operates at 1280 rpm and requires 1.6 brake horsepower. Since standard motor horsepower is 2.0, it will produce the necessary cfm and ESP for this job. 8

9 Performance data GROSS COOLING CAPACITIES 50BYN006 (5 TON) Air Entering Evaporator Cfm/BF Condenser Air 1500/ /0.30 Air Entering Evaporator Wet Bulb Temperature Ewb (F) 2500/0.40 Cfm Temp TC SHC kw TC SHC kw TC SHC kw TC SHC kw TC SHC kw BYN008 (7 1 2 TON) Air Entering Evaporator Cfm/BF Condenser Air 2250/ /0.34 Air Entering Evaporator Wet Bulb Temperature Ewb (F) 3750/0.43 Cfm Temp TC SHC kw TC SHC kw TC SHC kw TC SHC kw TC SHC kw LEGEND BF Bypass Factor Ewb Entering Wet-Bulb kw Compressor Motor Power Input (kilowatts) SHC Sensible Heat Cap. (1000 Btuh) TC Total Cap. (1000 Btuh) Gross Shaded area in table indicates nominal cfm values. NOTES: 1. Direct interpolation is permissible. Do not extrapolate. 2. Gross capacities do not include deduction of indoor-fan motor heat. 3. All capacities are based on nominal condenser airflow. SHC correction table SHC is based on 80 F db temperature of air entering the coil. Below 80 F edb, subtract (corr factor x cfm) from SHC. Above 80 F edb, add (corr factor x cfm) to SHC. BYPASS FACTOR (BF) ENTERING AIR DRY-BULB TEMP (F) under over 85 Correction Factor Use formula shown below. Correction Factor = 1.10 x (1 BF) x (edb 80). 4. The following formulas may be used. sensible capacity (Btuh) t ldb = tedb 1.10 x cfm t lwb = Wet-bulb temperature corresponding to enthalpy of air leaving evaporator coil (h). total capacity (Btuh) h lwb = hewb 4.5 x cfm Where: h = Enthalpy of air entering evaporator coil. 9

10 Performance data (cont) GROSS COOLING CAPACITIES (cont) 50BYN012 (10 TON) Air Entering Evaporator Cfm/BF Condenser Air 3000/ /0.031 Air Entering Evaporator Wet Bulb Temperature Ewb (F) 5000/0.051 Cfm Temp TC SHC kw TC SHC kw TC SHC kw TC SHC kw TC SHC kw BYN014 (12 TON) Air Entering Evaporator Cfm/BF Condenser Air 3600/ /0.09 Air Entering Evaporator Wet Bulb Temperature Ewb (F) 6000/0.11 Cfm Temp TC SHC kw TC SHC kw TC SHC kw TC SHC kw TC SHC kw LEGEND BF Bypass Factor Ewb Entering Wet-Bulb kw Compressor Motor Power Input (kilowatts) SHC Sensible Heat Cap. (1000 Btuh) TC Total Cap. (1000 Btuh) Gross Shaded area in table indicates nominal cfm values. NOTES: 1. Direct interpolation is permissible. Do not extrapolate. 2. Gross capacities do not include deduction of indoor-fan motor heat. 3. All capacities are based on nominal condenser airflow. SHC correction table SHC is based on 80 F db temperature of air entering the coil. Below 80 F edb, subtract (corr factor x cfm) from SHC. Above 80 F edb, add (corr factor x cfm) to SHC. BYPASS FACTOR (BF) ENTERING AIR DRY-BULB TEMP (F) under over 85 Correction Factor Use formula shown below. Correction Factor = 1.10 x (1 BF) x (edb 80). 4. The following formulas may be used. sensible capacity (Btuh) t ldb = tedb 1.10 x cfm t lwb = Wet-bulb temperature corresponding to enthalpy of air leaving evaporator coil (h). total capacity (Btuh) h lwb = hewb 4.5 x cfm Where: h = Enthalpy of air entering evaporator coil. 10

11 Performance data (cont) GROSS COOLING CAPACITIES (cont) 50BYN016 (15 TON) Air Entering Evaporator Cfm/BF Condenser Air 4500/ /0.35 Air Entering Evaporator Wet Bulb Temperature Ewb (F) 7500/0.45 Cfm Temp TC SHC kw TC SHC kw TC SHC kw TC SHC kw TC SHC kw BYN024 (20 TON) Air Entering Evaporator Cfm/BF Condenser Air 6000/ / ,000/0.40 Air Entering Evaporator Wet Bulb Temperature Ewb (F) Cfm Temp TC SHC kw TC SHC kw TC , SHC kw TC SHC kw TC SHC kw LEGEND BF Bypass Factor Ewb Entering Wet-Bulb kw Compressor Motor Power Input (kilowatts) SHC Sensible Heat Cap. (1000 Btuh) TC Total Cap. (1000 Btuh) Gross Shaded area in table indicates nominal cfm values. NOTES: 1. Direct interpolation is permissible. Do not extrapolate. 2. Gross capacities do not include deduction of indoor-fan motor heat. 3. All capacities are based on nominal condenser airflow. SHC correction table SHC is based on 80 F db temperature of air entering the coil. Below 80 F edb, subtract (corr factor x cfm) from SHC. Above 80 F edb, add (corr factor x cfm) to SHC. BYPASS FACTOR (BF) ENTERING AIR DRY-BULB TEMP (F) under over 85 Correction Factor Use formula shown below. Correction Factor = 1.10 x (1 BF) x (edb 80). 4. The following formulas may be used. sensible capacity (Btuh) t ldb = tedb 1.10 x cfm t lwb = Wet-bulb temperature corresponding to enthalpy of air leaving evaporator coil (h). total capacity (Btuh) h lwb = hewb 4.5 x cfm Where: h = Enthalpy of air entering evaporator coil. 11

12 Performance data (cont) ACCESSORY HEATING COIL CAPACITIES UNIT 50BYN STEAM DISTRIBUTING COIL* HOT WATER COIL CFM TC LAT Air P TC LAT (Btuh) (F) (in. wg) (Btuh) (F) GPM Water P Air P (Psig) (in. wg) 1, , , , , , , , , , , , , , , , , , LEGEND LAT Leaving Air Temperature (F) TC Total Heating Capacity (1000 Btuh) P Pressure Drop *Steam distributing coil 1 row, ratings based on 2 psig steam, 60 F entering air. Hot water coil 2 row, ratings based on 200 F entering water temperature, 20 F water temperature drop, 60 F entering air temperature NOTES: 1. Maximum allowable leaving air temperature 140 F. 2. Maximum operating limit for heating coils is 200 psig or 400 F. 3. To obtain capacities other than those given above, multiply the Btuh value from the Accessory Heating Coil Capacities table by the proper value from the Heating Capacity Correction Factor table. 4. Formulas: Leaving Air Temperature LAT = edb (F) + (TC Btuh/1.1 x cfm]) Gpm = TC (Btuh) (500 x T water [F]) 5. Reduced airflow (caused by dirty filters, loose or broken fan belts, etc.) over coil during cooling cycle may result in freeze-up of nearby heating coil. Since units normally require a low pressure switch cut-out setting at about 27 F, use of a freeze-up thermostat is recommended if heating coil is not drained or filled with an antifreeze solution. 6. Field supplied thermostat and control valve are required when using accessory heating coils. HEATING CAPACITY FACTORS STEAM COIL Steam Entering Air Temperature (F) Pressure Psig Water Temp (F) Drop HOT WATER COIL Entering Entering Air Temperature (F) Water Temp (F)

13 CONDENSER FAN PERFORMANCE 50BYN Bhp STATIC PRESSURE (in. wg) Cfm Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp 2, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , LEGEND Brake Horsepower Shaded areas require field-supplied drive. 13

14 Performance data (cont) EVAPORATOR FAN PERFORMANCE CFM EXTERNAL STATIC PRESSURE (in. wg) BYN Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp BYN Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp BYN Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp LEGEND Bhp Brake Horsepower NOTES: 1. Shaded areas require field-supplied drive. 2. Italics require field-supplied motor. 14

15 3,600 4,200 4,800 5,400 6,000 4,500 5,250 6,000 6,750 7,500 6,000 7,000 8,000 9,000 10,000 CFM EVAPORATOR FAN PERFORMANCE (cont) EXTERNAL STATIC PRESSURE (in. wg) BYN014 Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp BYN016 Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp BYN024 Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp LEGEND Bhp Brake Horsepower NOTES: 1. Shaded areas require field-supplied drive. 2. Italics require field-supplied motor. 15

16 Electrical data UNIT 50BYN V-PH-Hz VOLTAGE RANGE COMPRESSOR NO. 1 COMPRESSOR NO. 2 COMPRESSOR NO. 3 CONDENSER FAN INDOOR-FAN MOTOR POWER SUPPLY* Min Max RLA LRA RLA LRA RLA FLA Hp FLA Hp FLA MCA MOCP 208/ / / / / / LEGEND FLA Full Load Amps LRA Locked Rotor Amps MCA Minimum Circuit Amps MOCP Maximum Overcurrent Protective Device (see Note 1) NEC National Electrical Code RLA Rated Load Amps *Minimum Ckt Amps and MOCP Amps values per NEC (see Note 1). The overcurrent protective device for the unit shall be fuse or HACR circuit breaker (see Note 1). NOTES: 1. In compliance with NEC requirements for multimotor and combination load equipment (NEC Articles 430 and 440), the overcurrent protective device for the unit shall be fuse or HACR circuit breaker. Canadian units may be fuse or circuit breaker. 2. Wire sizing amps are a sum of 125% of the compressor RLA plus 100% of indoor fan motor FLA. 3. Motors are protected against primary single phasing condition. 4. Indoor-fan motors are 3-phase motors of same voltage as unit. 5. Three-phase voltage imbalance must not exceed 2 percent. 16

17 Typical wiring schematic, 50BYN units NOTES: 1. Fan motors are inherently thermally protected. 2. Three-phase motors are protected under primary single phase conditions. 3. Use conductors suitable for at least 194 F (90 C) when replacing factory wiring. 4. Use copper conductors only. 5. Wiring for field power supply must be rated at 165 F (75 C) minimum. C Compressor Contactor CB Circuit Breaker CLO Compressor Lockout CR Control Relay EQUIP Equipment GND Ground HPS High-Pressure Switch IFC Indoor-Fan Contactor IFM Indoor-Fan Motor IFP Indoor-Fan Protector LPS Low-Pressure Switch NEC National Electrical Code OFC Outdoor-Fan Contactor OFM Outdoor-Fan Motor OFP Outdoor-Fan Protector LEGEND TB Terminal Block TDR Time Delay Relay TRAN Transformer Terminal Block Connection Marked Terminal Unmarked Terminal Splice Factory Wiring Field Control Wiring 17

18 Controls Operating sequence All units require the addition of a thermostat accessory package to complete the control circuit. The sequence of operation may vary depending on which package is selected. Room-mounted thermostat The unit uses an electronic, communicating electronic, or mechanical thermostat mounted in the conditioned space. Fan circulation When the thermostat selector switch is set to the FAN position, the evaporator-fan motor will operate to provide air circulation. Cooling The evaporator will operate continuously or when the compressor runs, depending on the setting of the thermostat fan selector switch. When the thermostat closes (on a call for cooling), the control relay outdoor-fan contactor and compressor contactor(s) close. The control relay will start the indoor fan if it is not already running. The condenser fan contactor will start the condenser air fan and the compressor contactors will immediately start the compressor(s). The 50BYN024 unit as wired from the factory has two compressors on first stage and one on second stage; this may be changed (see application section of this product data). A second stage on 50BYN012 to 024 units will close if additional cooling demand is required, and will start the second-stage compressor. When the thermostat is satisfied, the second stage compressor will stop first, and then the first stage compressors will stop when cooling demand is satisfied. The condenser will also stop as soon as the first stage cooling is satisfied. Low ambient control on 50BYN units is accomplished with a refrigerant operated damper located on the condenser fan discharge. Low ambient operation does not affect operating sequence. A 5-minute timer (TDR [Time Delay Relay]) will prevent the compressor(s) from restarting for 5 minutes after any compressor has stopped. Heating The evaporator fan will operate continuously or when the compressor runs, depending on the setting of the thermostat fan selector switch. When the thermostat closes (on a call for heating), the thermostat activates the water or steam control valve to meet heating requirements. Carrier TEMP System thermostat The Carrier TEMP System thermostat works like a room thermostat, but provides for communicating control. The TEMP thermostat requires the addition of an accessory relay pack to interface with the unit. This relay pack may be mounted in the lowvoltage control compartment. The system operation is the same as stated in the Room-Mounted Thermostat section. All units The control circuit incorporates a currentsensing lockout relay (Cycle-LOC device) that locks off the compressor(s) when any safety device is activated (low- or high-pressure switches, condenser-fan motor overload or compressor internal overload). If any compressor safety device opens, the compressor(s) will stop and a 24-v signal will be sent to the X connection of the low-voltage terminal strip. The signal may be used to light an indicator light on the unit. Since the unit is protected by the Cycle-LOC device, the compressor(s) will not restart following a safety interruption unless the thermostat is satisfied without cooling operation. To reset the Cycle-LOC control device, manually turn the control power to the OFF, then back to the ON position. High- and low-pressure switches and motor overload protectors will reset automatically when the condition which caused device to trip has dropped below the reset condition. 18

19 Typical piping and wiring LEGEND Condenser Airflow Evaporator Airflow Power Wiring Control Wiring *NEC National Electrical Code NOTES: 1. Wiring and piping shown are general points of connection guides only and are not intended for or to include all details for a specific installation. 2. All wiring must comply with applicable local and national codes. 3. All piping must follow standard piping techniques. Refer to Carrier System Design Manual Part 3 for details. 4. Connect drain to building waste system and provide a trap of sufficient depth for unit static. 19

20 Application data Location For best results unit must be properly located and installed. Selected location should not be adjacent to an acoustically sensitive space, for example a conference room or executive office. The best location is in mechanical rooms in areas like elevators, restrooms, stairways, or similar spaces. The mechanical room should use construction methods which will help isolate the transmission of acoustical energy. Since these units typically use large quantities of ducted condenser air, select a location with the best access to outside window or wall to accommodate condenser air louver. Locate the unit as close to the wall opening as possible but allow space for return air inlet and access to the evaporator and condenser coil for cleaning. Units on the same floor should have a minimum of 6 feet between units to prevent recirculation of condenser air. Units floor to floor should have a minimum of 10 feet between units to prevent recirculation. Units should not be located with several units pulling condenser air from a small space between buildings, which may be recirculated. Recirculation of condenser air will result in increased head pressure which may cause units to trip on high pressure. There are several methods for applying 50BYN units in different space applications. See page 23 for recommended equipment room applications and locations of key components. Moving units into existing buildings Carrier s 50BYN units are designed to pass through most 36-in. door openings. The filter rack and duct mounting flanges may also be removed. The height of the 20 ton unit exceed some door openings, see section on splitting the 20 ton unit. Unit mounting stand When units are mounted to use a existing window height, a field-supplied steel mounting stand is recommended. The stand should be built rigid enough to support the weight of the unit and braced to prevent any side to side movement of the stand. A mounting height higher than the window sill height is recommended, which allows the condenser duct to be pitched back to the louver in the window for rain elimination and drainage. Unit isolation Unit compressors are internally isolated and the compressor compartment is lined with acoustical insulation. If additional vibration isolation is desired, rubber in shear pads are recommended under the four corners of the unit. Spring isolation is not recommended. All duct connections to the unit should be made with flexible connections to prevent any transmission of vibration of the ductwork. Accessories Condenser air filters are recommended on the condenser air inlet to prevent build up of dirt and debris, which are pulled in with the condenser air and can plug the coil. This filter will reduce the need to clean the condenser coil. See page 23 for recommended location of condenser air filters. Outside air connections and air economizer Outdoor ventilation air is required for most spaces and the use of an outdoor economizer cycle can save cooling energy. Carrier s 50BYN units can be applied with ventilation control options, including CO2 activated ventilation or differential economizer. Several methods of bringing the air into the unit are possible. A mixing box with dampers to control outdoor and return air is the best method. A mixing box assures adequate mixing of both air streams. When an integrated economizer cycle (compressors can operate with full outdoor air) is used, it is recommended that an evaporator defrost thermostat be put in the unit. This control will turn off the compressors when frost begins to form on the evaporator coil. Heating coils Accessory steam and hot water coils are mounted in the unit return air before the cooling coil. The filter rack provided with the unit is removed, the coil mounted in the same position and the filter rack reattached to the coil. The same filter rack may be used with ducted or free return. Care must be exercised in location of outside ventilation or economizer air in to the unit when heating coils are used to prevent coil freeze up. Make sure adequate mixing of return and outside air is provided to prevent below freezing temperatures at any point of the coil. Also be sure that dampers close off outdoor air during unit shutdown. Spring return outdoor air dampers are recommended. Discharge plenum When unit is to be used directly in the space to be conditioned without ductwork attached, a discharge plenum with acoustical lining and a discharge grille on the unit are recommended. It is recommended that the fan be slowed down to deliver no more than nominal cfm for best acoustical performance. Condenser air filter racks, mixing boxes with outdoor air dampers and economizers, and discharge plenums may be field fabricated or are available through specialty accessory manufacturers. 20