REMOTE RACK SYSTEM OWNERS MANUAL INSTALLATION OPERATIONS - MAINTENANCE 4401 Blue Mound Rd. Fort Worth, TX 76106 Phone: (714) 870-8661 Toll-Free: (800) 833-1106 Fax: (714) 870-6473 www.kairak.com KAIRAK, a Division of ITW Food Equipment Group, LLC. All Rights Reserved ANSI/UL Std. 1995-CAN/CSA C22.2 No. 236 M05 (Intertek #4004142)
1. INTRODUCTION... 3 2. COMPLETION REPORT SERVICE RECORD WARRANTY... 3 3. FEATURES... 4 3.1 CONDENSING UNIT... 4 3.2 REFRIGERANT... 5 3.3 CONTROL PANEL... 5 3.4 ELECTRICAL DEFROST... 5 3.5 ELECTRICAL REQUIREMENTS... 6 3.6 STANDARD COMPONENTS... 6 3.7 ACCESSORIES STANDARD... 6 3.8 HEAD PRESSURE CONTROL VALVE... 6 3.9 ETL APPROVAL... 6 3.10 WALK IN EVAPORATOR COILS... 7 4. DIMENSIONAL DATA... 8 5. INSTALLATION... 9 5.1 RECEIPT AND INSPECTION OF EQUIPMENT... 9 5.2 LIFTING INSTRUCTIONS... 9 5.3 LOCATION AND VENTILATION... 10 5.4 ROOF PLATFORM REQUIREMENTS... 11 5.5 PITCH POCKET... 11 5.6 ELECTRICAL... 11 5.7 PLATFORM DIMENSIONS... 13 5.8 WIRING DIAGRAM WALK IN COOLER... 14 5.9 WIRING DIAGRAM WALK IN FREEZER... 15 6. REFRIGERATION... 16 6.1 PIPING... 16 6.2 STANDARD PIPING PROCEDURES... 17 6.3 LEAK TESTING... 17 6.4 SYSTEM EVACUATION... 18 6.5 SYSTEM CHARGING (LESS FLOODED HEAD PRESSURE CONTROL)... 18 6.6 SYSTEM CHARGING (WITH FLOODED HEAD PRESSURE CONTROL)... 18 6.7 THERMAL EXPANSION VALVE... 20 6.8 HOT GAS BYPASS... 21 6.9 FAN CYCLE CONTROL... 21 7. START-UP PROCEDURE... 21 7.1 CONDENSING UNITS... 22 7.2 EVAPORATOR COIL BEFORE START UP... 22 7.3 EVAPORATOR COIL AFTER START UP... 23 7.4 OPERATIONAL CHECK-OUT... 23 7.5 TIMER DIAL... 25 7.6 SHUT DOWN... 26 7.7 SYSTEM RESTART AFTER SHUT DOWN... 26 8. MAINTENANCE... 27 8.1 AIR-COOLED CONDENSER... 27 KAIRAK REMOTE RACK SYSTEM PAGE 1
8.2 ELECTRICAL AND PIPING CONNECTIONS... 27 8.3 CRANKCASE LUBRICATION... 27 8.4 MAINTENANCE CHECKLIST (AT THE RACK)... 28 8.5 EVAPORATOR COIL... 28 8.6 HEATER REPLACEMENT IN LOW TEMP EVAPORATOR COIL... 29 9. TROUBLESHOOTING... 30 10. TABLES AND CHARTS... 39 10.1 TEMPERATURE PRESSURE CHART... 39 10.2 LINE SIZING FOR REFRIGERATION SYSTEMS... 40 Table 1: Pressure loss... 40 Table 2: Equivalent Feet of Pipe Due to Valve and Fitting Friction... 40 Table 3: Weight Of Refrigerant... 41 Table 4: Recommended Remote Condenser Line Sizes.... 42 Chart 5: Recommended Line Sizes For R-404A... 43 Chart 6: Recommended Line Sizes For R-404A (Cont d)... 44 11. WIRING DIAGRAMS... 45 11.1 SINGLE EVAPORATOR W/WO DEFROST TIMER... 45 11.2 SINGLE EVAPORATOR W/DEFROST TIMER ONLY... 46 11.3 MULTIPLE EVAPORATORS W/DEFROST TIMERS ONLY... 47 11.4 SINGLE EVAPORATOR SINGLE PHASE DEFROST/EVAPORATOR FAN... 48 11.5 SINGLE EVAPORATOR DEFROST AND EVAPORATOR FAN CONTACTORS... 49 11.6 MULTIPLE EVAPORATOR W/FAN CONTACTORS/NO HEATER LIMIT DEFROST... 50 11.7 MULTIPLE EVAPORATOR WITH HEATER LIMIT DEFROST AND EVAPORATOR... 51 11.8 MULTIPLE EVAPORATOR DEFROST AND EVAPORATOR FAN CONTACTORS W/UNIT COOLER HOLDOUT RELAY... 52 11.9 DEFROST CONTACTOR W/EVAPORATOR HOLDOUT RELAY W/O HEATER LIMIT... 53 11.10 DEFROST CONTACTOR W/EVAPORATOR HOLDOUT RELAY W/HEATER LIMIT... 54 11.11 MULTIPLE EVAPORATORS W/DEFROST SWITCHES IN SERIES, W/O HOLDOUT RELAYS/HEATER LIMITS... 55 12. PARTS LIST... 56 13. WARRANTIES... 63 14. REMOTE REFRIGERATION START-UP AND INSTALLATION COMPLETION REPORT AND RECORD... 65 14.1 REMOTE RACK CONDENSING UNIT... 66 14.2 WALK-INS EVAPORATOR COIL... 71 14.3 FIXTURES PREP TABLES COLD RAILS UNDER-COUNTER EQUIPMENT STANDS ALL OTHER ITEMS... 75 14.4 INSTALLTION/PIPING... 77 PAGE 2 KAIRAK REMOTE RACK SYSTEM
REMOTE RACK SYSTEM 1. INTRODUCTION Kairak is committed to producing environmentally friendly and sustainable product offerings without sacrificing quality or reliability. Kairak Remote Rack system assures customers maximum energy savings and a substantially smaller environmental footprint. Kairak systems have been successfully integrated into LEED certified buildings. The Kairak air cooled Remote Rack cooling system utilizes safe HFC s and offers excellent operating efficiency by using multi-circuited condensers for up to 20 compressors and ice makers. This high operating efficiency is made through effective use of the condenser coil surface area. The large condenser coils provide the unit with summer design temperature differences (TD s) lower than traditional designs allow. Lower design TD s produce lower condensing temperatures which produce lower compression ratios and higher compressor capacities, thereby reducing operating cost. Kairak Remote Rack systems are easier to install, easier to service and much less expensive to operate. Complete factory assembly eliminates on-sight construction costs of built-up systems by refrigeration technicians and electricians in the field. The Kairak Remote Rack system is designed primarily for institutional food service operations including: hospitals, universities, schools, hotels, restaurants, coffee shops and convenience stores. Kairak Remote Rack systems pull fresh air over the compressor bodies to reduce their operating temperature. Compressor ventilation has become increasingly important to extend its life span. R-404A refrigerant is used for all applications. 2. COMPLETION REPORT SERVICE RECORD WARRANTY The Kairak completion report and record is located at the back of this manual. This must be filled out and a copy sent to Kairak for their review to begin warranty coverage of your rack system. KAIRAK REMOTE RACK SYSTEM PAGE 3
REMOTE REFRIGERATION RACK REFRIGERANT LINES IN WALL WALK-IN EVAPORATOR Figure 1 3. FEATURES 3.1 CONDENSING UNIT Kairak Remote Rack systems will typically provide many years of trouble-free operation with minimal maintenance. The length of service from a condensing unit is greatly affected by the care taken during the original installation. Cleanliness is absolutely mandatory when installing a condensing unit. Utmost care has been taken at the factory to insure that the unit is free of all contamination. The factory-applied seals must not be removed until the unit is ready for installation. All tubing, valves, and fittings must be carefully inspected to insure cleanliness. The required electrical supply must be provided to the condensing unit control panel. The voltage at the motor-compressor terminals should be checked during start-up and unit operation under full load to insure a tolerance of +/- 10% of the system nameplate rating. The lubrication recommendations for the motor-compressor and fan motors (where applicable) must be carefully adhered to. PAGE 4 KAIRAK REMOTE RACK SYSTEM
CAUTION: Do not remove factory-applied seals before installation to aid in keeping contaminates from entering system. 3.2 REFRIGERANT R404a is used for all walk-in coolers, walk-in freezers, under counter refrigerated bases, pan chillers and prep tables. 3.3 CONTROL PANEL Each Kairak Remote Rack system is provided with a pre-wired control panel for single point connection with main disconnects. The control panel is designed to assure efficient unit operation and provide a pre-selected sequence of operation during the refrigeration and defrost cycles. Each control panel is equipped with a main disconnect, motor compressor breakers, contactors, fan motor capacitor, defrost time clock for freezer, and wiring diagram for service. The control panel only requires 3 wires for power supply (and neutral if indicated) plus ground wire, at least 4 wires for defrosts heaters and evaporator coil fan motors in freezer. All system circuits are labeled for easy identification. NOTE: Refer to electrical schematics to determine control wire quantities for defrost and alarm features. 3.4 ELECTRICAL DEFROST An electrical defrost heater in the freezer is field connected to the time clock in the control panel. Defrost is initiated by the time clock and stopped by a termination solenoid in the time clock connected to defrost limit thermostat in the freezer coil. The time clock is set to fail safe termination period at 45 minutes. NOTE: The freezer requires four defrost cycles per day: 4:00 A.M. and 10:00 A.M., 4:00 P.M. and 10:00 P.M. KAIRAK REMOTE RACK SYSTEM PAGE 5
3.5 ELECTRICAL REQUIREMENTS The Kairak Remote Rack system is equipped with 208-230 volts, 3 phase, 60 hertz power supply. 460-480 volts power supply is available on request. 3.6 STANDARD COMPONENTS The Kairak Remote Rack system consists of multiple hermetic/glacier scroll compressors, multicircuited condenser with heavy duty fan motors, oversized receivers, and factory installed accessories, evaporator coils with T-Stat, solenoid valve, TX valve, electrical panel and all electrical controls. 3.7 ACCESSORIES STANDARD Standard accessories factory installed in the Kairak Remote Rack system include: drier, sight glass, head pressure control, dual pressure control, pre-wired control panel and fan cycle switches. 3.8 HEAD PRESSURE CONTROL VALVE A head pressure control valve is provided as a standard on all outdoor rack systems to provide stable head pressure in low ambient temperatures. The valve will maintain 180 lbs. PSIG in the receiver. This is accomplished by the modulation of the valve regulating flow from the condenser and the discharge line. It provides a minimum head pressure to insure refrigerant flow at the expansion valve. It also provides a minimum head pressure to assure refrigerant flow at the TXV and provide hot gas to the receivers for cold start situations. 3.9 ETL APPROVAL The Kairak Remote Rack system is approved by Intertek and displays the ETL label on the control panel. ETL listed under the standard for heating and cooling equipment, ANSI/UL Std. 1995- CAN/CSA C22.2 No. 236 M05 (Intertek #4004142) PAGE 6 KAIRAK REMOTE RACK SYSTEM
3.10 WALK IN EVAPORATOR COILS FREEZER A lower temperature electric defrost low silhouette evaporator coil for the freezer is provided with each Kairak Remote Rack system. The evaporator coil draws air in through the coil and discharges it through the fans. For best results, the evaporator coil should be located 18 from the back wall and blow towards the door. Thermostat, solenoid valve and TX valve are installed in the evaporator coil at the factory. A suction line P-Trap should be installed at evaporator coil by installer in the field for improved oil return. COOLER A medium temperature low silhouette evaporator coil for the cooler is provided with each Kairak Remote Rack system. Air defrost is used for defrosting the evaporator coil. The evaporator coils are provided with a thermostat, solenoid valve and TX valve and air defrost timer. Units are pre-piped and pre-wired for final connections. A suction line P-Trap should be installed at evaporator coil by installer in the field. CAUTION: Kairak Remote Rack systems are tested and assembled under strict quality assurance procedures. Each unit is tested and charged with nitrogen prior to shipment. Use caution and exercise safety procedures at all times when preparing for final hook-up. KAIRAK REMOTE RACK SYSTEM PAGE 7
4. DIMENSIONAL DATA H Figure 2 KAIRAK MODEL DIMENSION (INCH) NUMBER L W H KMR-4 48 48 54 KMR-6 72 48 54 KMR-8 96 48 54 KMR-10 120 48 54 KMR-12 144 48 54 KMR-14 168 48 54 KMR-16 192 48 54 KMR-18 216 48 54 KMR-20 240 48 54 CAUTION: Installation clearance: a minimum of 3 feet on all sides. NOTE: Refrigeration lines are stubbed at right end of Rack. Electrical lines are stubbed at left end of Rack. Control Panel adds 10 to length of unit. PAGE 8 KAIRAK REMOTE RACK SYSTEM
5. INSTALLATION 5.1 RECEIPT AND INSPECTION OF EQUIPMENT The utmost care has been taken in crating your Kairak Remote Rack system to protect it against damage in transit. Carefully inspect your unit for damage that may have occurred during delivery. If damage is detected, you should save all crating materials and make a note on the carrier s Bill of Lading describing the damage. Pictures should be taken to document the damage. A freight claim should be filed immediately with the freight carrier. If damage is later noted, either during or immediately after installation, contact the respective carrier and file a freight claim. There is a fifteen (15) day limit to file a freight damage claim with most carriers. Under no condition may a damaged unit be returned to Kairak without first obtaining written permission (return authorization). Any damage must be documented and reported to Kairak. The documentation as well as pictures showing damage should be included. Contact Kairak customer care at (800) 833-1106. 5.2 LIFTING INSTRUCTIONS The Kairak Remote Rack system is a heavy piece of machinery and can weigh from approximately 500 to 10, 000 lbs. Careful consideration of lifting procedures should be made before the unit is lifted by any means. Cables or other load-bearing devices must not be allowed to press against the unit frame body, piping, electrical conduit or the motor control panel. The only area of the unit designed to carry the lifting load is the base. Lifting loads should be distributed evenly around the base to avoid twisting. When lifting the unit by crane, the lifting space provided in the lower portion of the base frame is the recommended attachment points for the lifting cables. (See Figure 3). A spreader bar or similar device should be used to prevent the lifting cables from contacting the unit KAIRAK REMOTE RACK SYSTEM PAGE 9
SPREADER SPREADER PLATFORM Figure 3 WARNING: CABLES OR OTHER LOAD-BEARING DEVICES MUST NOT BE ALLOWED TO PRESS AGAINST THE UNIT FRAME BODY, PIPING, ELECTRICAL CONDUIT OR THE MOTOR CONTROL PANEL. 5.3 LOCATION AND VENTILATION The Kairak Remote Rack unit must be located in an area which allows easy access for installation and service of all electrical lines, refrigeration piping and any accessory equipment. The unit must be level to insure proper lubrication. A minimum of 3 feet clearance must be provided on all sides of the unit. Equipment should be mounted on a smooth, hard, level surface. Mounting surface should be rigid and provisions should be made to prevent noise transmission (structural) to surrounding areas. Air PAGE 10 KAIRAK REMOTE RACK SYSTEM
cooled equipment should not be installed under low structural overhangs which can cause condenser air recirculation restriction. Two units side by side should have a minimum of 1 ½ unit width between them. Care should be taken to prevent air from other sources from entering condenser if this air is at an elevated temperature. 5.4 ROOF PLATFORM REQUIREMENTS The suggested roof platform requirements are shown in Figure 4. The location and installation of all equipment should be in accordance with all local code requirements. The unit can usually be placed directly on the roof platform since each compressor is mounted on vibration isolation pads. For light roof construction vibration isolation pads can be used underneath the supporting frame. Figure 4 5.5 PITCH POCKET A. 9 x 24 pitch pocket must be provided for refrigeration lines. After lines are installed, backfill opening with hot pitch and make sure there are no leaks. 5.6 ELECTRICAL To insure operation of equipment and reduce the possibility of electrical power interruption, the following precautions must be observed: KAIRAK REMOTE RACK SYSTEM PAGE 11
A. All electrical must be done in accordance with the National Electrical Code and existing local codes. B. The power supply must be the same as that which appears on the data plate of the motors. C. An adequate power supply must be provided. D. Voltage fluctuations in excess of +/- 10% should be corrected. E. 120 volts, 1 phase, 60 Hz power supply must be provided for walk-in cooler. F. All unit wiring terminals should be checked for tightness before power is applied to the equipment. G. When wiring is completed, fan motors should be checked for proper rotation. All fan motors of multiple fan equipment have been factory wired to operate with the same rotation. If rotation is found incorrect, reverse two of the three leads on the main incoming power. Before starting a Kairak Remote Rack System, check that all breakers and motor protective devices are in place and that all wiring is secure. A wiring diagram for troubleshooting the unit is included on the cover. PAGE 12 KAIRAK REMOTE RACK SYSTEM
5.7 PLATFORM DIMENSIONS Figure 5 KAIRAK MODEL NUMBER KAIRAK REMOTE RACK SYSTEM DIMENSIONS ENCLOSURE DIMENSION (INCH) WEIGHT (LBS) L W H CONDENSER FAN MOTORS ROOF PLATFORM DIMENSIONS (INCHES) OVERALL PLATFORM CURB OPENING 208V/1PH/60Hz QTY L W H A B KMR-4 440 48 48 54 2 62 57 6 20 8 KMR-6 640 72 48 54 2 86 57 6 20 8 KMR-8 695 96 48 54 3 110 57 6 20 8 KMR-10 870 120 48 54 4 134 57 6 23 8 KMR-12 1000 144 48 54 5 158 57 6 23 8 KMR-14 1240 168 48 54 5 182 57 6 23 8 KMR-16 1440 192 48 54 6 206 57 6 30 8 KMR-18 1600 216 48 54 7 230 57 6 30 8 KMR-20 1820 240 48 54 8 254 57 8 30 8 KAIRAK REMOTE RACK SYSTEM PAGE 13
5.8 WIRING DIAGRAM WALK IN COOLER Figure 6 PAGE 14 KAIRAK REMOTE RACK SYSTEM
5.9 WIRING DIAGRAM WALK IN FREEZER Figure 7 KAIRAK REMOTE RACK SYSTEM PAGE 15
6. REFRIGERATION 6.1 PIPING Connect suction and liquid lines with the evaporator coils and condensing unit on the roof. Leave access tubing in the attic space and backfill opening with hot pitch after installation so that there are no leaks. Precautions must be taken to insure no foreign material enters the pipes during installation. All piping must be supported with hangers that can withstand the combined weight of tubing, insulation, valves and fluid in the tubing. Refrigeration piping must be in compliance with the National and local code and apply good refrigeration standard practice for proper operation of the system. CURBED OPENING FOR ELECTRICAL LINES PLATFORM FINISHED ROOF CURBED OPENING FOR REFRIGERATION LINES P TRAP EVERY 10 FT. EVAPORATOR COIL P TRAP @ SUCTION RISER INVERTED TRAP AT END OF RISER Figure 8 PAGE 16 KAIRAK REMOTE RACK SYSTEM
6.2 STANDARD PIPING PROCEDURES A. Refrigeration pipes should be sized properly. (See Chart 5) B. For the point of connection at the Remote Rack unit and the condensing unit or evaporator fixture, the pipe sizes may not be the same size as the interconnecting pipes. C. Use only dehydrated copper tubing listed for refrigeration grade and application. Only long radius elbows are to be used. D. Use a minimum of 15% silver solder alloy on suction and liquid lines. Dry nitrogen should be passed through when brazing the lines at a low pressure to eliminate oxidation and scaling. E. Suction lines should be sloped ½ for every 10 feet towards the remote rack. P traps should be installed at the bottom of each suction riser and at least every 10 feet of the riser. Inverted traps are also necessary on the top of the risers. This will allow good oil return for the compressors. Double risers are highly recommended on the large suction lines with a high capacity and parallel system, ran parallel, to compensate during minimum load and full load. F. Suction lines should be insulated using listed insulation and plenum rated. The installer must select the correct thickness of the insulation material. At a minimum, insulation should have a ¾ wall thickness. Any pipe insulation located outdoors should be covered and waterproofed to protect it from rain and UV. G. Installers should provide and add isolation valves on suction and liquid to be able to isolate and service evaporator coils in walk-ins, fixtures, reach-ins, prep tables, under counters or any other units. 6.3 LEAK TESTING After all refrigeration lines are connected, the entire system must be leak tested. Particular care should be given to those parts which will be inaccessible at a later date. Pressurize pipes with nitrogen at 300 PSI for at least 48 hours. The use of an electric leak protector is highly recommended because of its greater sensitivity to small leaks. KAIRAK REMOTE RACK SYSTEM PAGE 17
6.4 SYSTEM EVACUATION With refrigerant piping completed and leak tested, equipment is ready to evacuate. Do not use compressor to evacuate system. A quality vacuum pump of 500 microns vacuum is necessary for adequate and dependable system vacuum. Moisture in a refrigeration system can cause corrosion, expansion valve freeze-up and oil sludge. Attach vacuum pump to both high and low side of the system through compressor service valves and evacuate to 500 microns (all service valves*, hand valves and solenoids must be open during evacuation). It is suggested that the vacuum pump be run for a period of time after vacuum has been reached. *Service valves are back setting valves and must be mid-position to open both sides of the system. 6.5 SYSTEM CHARGING (LESS FLOODED HEAD PRESSURE CONTROL) With system wired, piped and evacuated, the unit is ready for refrigerant charging. All charging lines and manifolds must be evacuated prior to admitting refrigerant into the system to prevent contaminating the system with non-condensable. Connect charging line to receiver outlet valve and admit liquid refrigerant into high side of system until flow stops due to pressure equalization between high side and drum pressure. Backseat outlet valve and disconnect charging line. Connect charging line to compressor suction service valve and admit vapor into low side system. Energize equipment and continue to admit vapor into low side of system until liquid line sight glass clears, indicating a fully charged system. It may be necessary to defeat low pressure control on initial start to prevent nuisance trip until low side pressure is above cut out point of control. 6.6 SYSTEM CHARGING (WITH FLOODED HEAD PRESSURE CONTROL) Initial charging is the same as outlined in Less flooded head pressure control. Do not adjust control valves. These are either factory preset or non-adjustable, depending on size. The non-adjustable valves are set at 180 psi for by pass. PAGE 18 KAIRAK REMOTE RACK SYSTEM
Set unloaders (if supplied) to load compressors to 100% while charging. Add additional refrigerant to bring total up to required charge as listed on the system ETL label located on the control panel or the system drawings provided. For the low side charge, energize equipment and continue to admit vapor until liquid line sight glass clears indicating a fully charged system. It may be necessary to defeat low pressure control on initial start to prevent nuisance trip until low side pressure is above cut out point of control. This is a continuation of system charging and must be performed before equipment can be left operating and unattended. This will involve checking and adjusting of all safety and operating controls (pressure and temperature controls have not been set at the factory). Adjust and confirm that the settings are correct and that all controls function properly. Do not attempt to function safety controls without some means of stopping compressor in event of extreme high or low pressure conditions that could damage the equipment. If controls fail to function at set points, determine cause and correct. Jumping any safety control other than for testing purposes is dangerous to personnel and equipment and nullifies equipment warranty. Energize crankcase heaters and allow a minimum of 24 hours operation before a compressor start. A. High Pressure Control -connect a gauge to the compressor discharge service valve. Stop the condenser airflow by stopping fans on air cooled equipment or restricting water flow on water cooled equipment. Control should open immediately when discharge pressure reaches control set point. B. Low Pressure (Pump-Down) Control Connect a gauge to the compressor suction service valve. Throttle receiver outlet valve to lower suction pressure at compressor. Compressor should pump-down and be de-energized when suction pressure reached cut-out setting of control. Open receiver outlet valve and observe rise in pressure at compressor suction connection. Compressor should be energized when pressure reaches cut-in setting of control. C. Oil Pressure Control Copeland Compressor jumper between terminals T1 and T2 of the oil pressure safety control. Compressor should run approximately 120 seconds and cycle off. Remove jumper and reset control. Check operating oil pressure. This is the differential between oil pump discharge pressure and suction pressure and should be a minimum of 10 psig. After several hours running time check oil level in compressor, acceptable oil level is approximately ¼ on sight glass. KAIRAK REMOTE RACK SYSTEM PAGE 19
6.7 THERMAL EXPANSION VALVE Adjust superheat setting to job requirements. To correctly determine superheat: A. Measure the temperature of the suction line at the point the bulb is clamped. B. Obtain the suction pressure that exists in the suction line at the bulb location by either of the following methods: If the valve is externally equalized, a gauge in the external equalizer line will indicate the desired pressure directly and accurately. OR Read the gauge pressure at the suction valve of the compressor. Add the estimated pressure drop through the suction line between bulb location and compressor suction valve to the gauge pressure. The sum of the gauge reading and the estimated pressure drop will equal the approximate suction line pressure at the bulb. C. Convert the pressure obtained (above) to saturated evaporator temperature by using a temperature-pressure chart. D. Subtract the temperature reading of the suction line at the point of the bulb and the converted saturated evaporator temperature from the chart. The difference is superheat. E. (Figure 9) illustrates a typical example of superheat measurement on a refrigeration system using refrigerant 22. The temperature of the suction line at the bulb location is read at 52 F. The suction pressure at the evaporator bulb location is read at 68 psig which is equivalent to a 40 F saturation temperature. 40 F subtracted from 52 F = 12 F superheat. PAGE 20 KAIRAK REMOTE RACK SYSTEM
Figure 9 6.8 HOT GAS BYPASS (If Supplied) connect gauge to compressor suction service valve. Throttle receiver outlet valve to lower suction pressure at compressor. Hot gas regulator should begin to open as suction pressure approaches design suction pressure. This should be done before unit has bulled down to design condition. 6.9 FAN CYCLE CONTROL The fan cycle control is located at the discharge lines or at the compressor discharge service valve. The non-adjustable fan cycles are set to close at 260 psi and open at 190 psi. The adjustable fan cycle control must be set and adjusted per the factory settings as indicated in the system rack drawings. 7. START-UP PROCEDURE After the installation has been completed, before beginning start-up procedures the following checks should be performed: KAIRAK REMOTE RACK SYSTEM PAGE 21
7.1 CONDENSING UNITS A. Check electrical connections to insure all connections are properly tightened. Verify supplied voltage rating and phase meet system requirements as listed on the system ETL label located on the control panel. B. Check the motor-compressor oil level before start-up. The oil level should be at or slightly above the center of the sight glass. To add oil, use only manufacturer recommended oil as noted on each compressor tag. C. Insure that the rubber grommets are installed under the motor-compressor mounting nuts and that the motor compressor rides freely on its mounting vibration isolators. D. Check the high and low pressure controls and all other safety controls. Adjust if necessary. E. Check the walk-in cooler and freezer thermostats for correct operation. Confirm solenoids are opening and closing as required. F. Tags are provided to indicate refrigerant used in the system. G. The instruction manual, bulletins, tags, etc., are attached to the unit and should be placed inside the electrical panel for future reference. H. Observe system pressures during initial operation. Do not add oil while the system is short of refrigerant unless the oil level is dangerously low. I. Open all isolation valves, including all service valves at the compressors suction and discharge and at the receivers. Check that all Rotalock nuts are tightened securely. Tighten all valves to avoid leaks after start up. WARNING: DO NOT OVERCHARGE WITH OIL. 7.2 EVAPORATOR COIL BEFORE START UP A. Make sure system is wired correctly. Verify voltage rating. B. Check to make sure all electrical terminals are tight. PAGE 22 KAIRAK REMOTE RACK SYSTEM
C. Check fan set screws to confirm they are tight D. Check unit to confirm it is mounted securely using all hangers and is as level as possible. E. Make sure the drain connection is tightened to the drain line securely. F. Pour water into the drain pan to check for complete drainage of the drain pan and drain line. 7.3 EVAPORATOR COIL AFTER START UP A. On initial start-up for the freezer evaporator coil, the fans will not start until the coil temperature reaches approximately 25 F. B. Check the expansion valve superheat setting. It is important that the valve is set properly for efficient operating and even frost formation. C. Make sure the drain line heater is working properly. D. Heavy moisture loads are usually encountered when starting a system for the first time. This will cause a rapid frost build-up that will need to be closely watched. Manually defrost the unit as required. E. Observe the system as it goes through the first defrost cycle to make sure the timer, defrost heaters, termination thermostat and other system components function properly. 7.4 OPERATIONAL CHECK-OUT Only after the system has operated for at least two hours at normal operating conditions without any indications of malfunctions should it be allowed to operate overnight on automatic controls. A thorough re-check of the entire system operation should be made as follows: A. Check the motor-compressor head and suction pressure. If the pressures are not within the system design limits, determine why and take corrective action. B. Check the liquid line sight glass and expansion valve operation. If there are indications that more refrigerant is required, leak test all connections and system components and repair any leak before adding refrigerant. KAIRAK REMOTE RACK SYSTEM PAGE 23
C. Observe the oil level in the motor-compressor crankcase sight glass and add oil as necessary to bring the level to the center of the sight glass. D. Thermostatic expansion valves must be checked for proper superheat settings. Feeler bulbs must be positive thermal contact with the suction line. Valves with high superheat settings produce little refrigeration and poor oil return. Too little superheat causes low refrigeration capacity and promotes liquid slugging and compressor bearing washout. Liquid refrigerant must be prevented from reaching the crankcase. If proper controls cannot be achieved with the system in normal operation, a suction accumulator must be installed in the suction line just ahead of the motor-compressor to prevent liquid refrigerant from reaching the motor-compressor. E. Using suitable instruments carefully check line voltage and amperage at the compressor terminals. Voltage must be +/- 10% of that indicated on the compressor nameplate rating. If amperage draw is excessive, immediately determine the cause and take corrective action. On three phase motor-compressor units, check to see that a balanced load is drawn by each phase. F. Check the fan motor on air-cooled condensers and in walk-in evaporator coils for correct rotation. Fan motor mounts should be carefully checked for tightness and proper alignment. G. High pressure controls on condensing unit using R-404 should be set to cut out at 350 PSIG. The cut-out point of these controls should be checked by stopping the condenser fan and simultaneously monitoring the head pressures with an accurate gauge. H. Re-check all safety controls and operating controls for proper operation and adjust if necessary. I. Check the defrost time clock for initiation, termination and length of defrost period. The standard defrost timer furnished by Kairak provides frequency controls including a failsafe feature that automatically terminates defrost after a set period of time if the termination thermostat fails to function properly. The standard timer is furnished with a 240 volt clock motor and has a contact rating of 40 amps at 240 volts. (See Figure 10 below) PAGE 24 KAIRAK REMOTE RACK SYSTEM
To set the number of defrost cycles every 24 hours, pull the pins out and set at the desired cycle off times. Each pin represents a 15 minute interval. Pins pulled out away from center of time clock represent refrigeration off and defrost on (See Figure 10, shown in red). Pins pushed toward center indicate refrigeration on and defrost off. Make sure time clock is set to correct time of day. Kairak recommends 4 times a day defrost for a typical walk in freezer, 45 minutes each defrost period, set at 4:00 A.M. and 10:00 A.M., 4:00 P.M. and 10:00 P.M. (See Figure 10). To set the time of day, rotate the disc clockwise until the arrow lines up the correct time of day. Note that the clock face is divided into 24 hours. J. The time should initially be set for 4 defrost cycles per day. Each installation should be checked so the system operates efficiently with a minimum number of defrost cycles. The fail-safe works more efficiently with a minimum number of defrost cycles. The failsafe setting should not normally exceed 45 minutes because of danger of overheating the unit if the defrost cycle is prolonged too long. 7.5 TIMER DIAL On Cycle - Pins In Off Cycle - Pins Out (Shown in red) Timer shown with clock set at 8 P.M. Figure 10 KAIRAK REMOTE RACK SYSTEM PAGE 25
A. Dual pressure controls settings on the condensing unit should be cut in and out close to: R-404A High Low (R-404A) Fixture Description Cut Out psig In psig Out psig Walk-In Freezer 350 25-30 5 Walk-In Cooler 350 45-55 20 7.6 SHUT DOWN A. Equipment which will not be required to operate for a period of time should be secured by storing refrigerant charge in the receiver or condenser. B. Front seal the receiver outlet valve. Set thermostat at a setting below system temperature to insure that liquid line solenoid is energized. Defeat the low pressure control and allow unit to pump down to a suction pressure of approximately 5 psig. It may be necessary to repeat pump-down as some refrigerant will remain in oil and will slowly boil off. When suction pressure holds at 5 psig, front seal suction service valve. Lock disconnect in position. C. On units with water-cooled condensers, special precautions must be taken to completely drain the vessels to prevent freezing if ambient should be below 32 F. D. Inspect system for possible worn or faulty components and repair if required. 7.7 SYSTEM RESTART AFTER SHUT DOWN A. A thorough leak test should be performed. B. Coil(s) should be checked for dirt accumulation or obstruction and cleaned if necessary. C. Energize crankcase heaters and allow a minimum of 24 hours operation before a compressor restart. D. Install gauges, start system and check for correct refrigerant charge, proper system operation and balance. PAGE 26 KAIRAK REMOTE RACK SYSTEM
8. MAINTENANCE 8.1 AIR-COOLED CONDENSER The air-cooled condenser(s) should be cleaned with a brush and vacuum cleaner every four to six months to remove all accumulations of dust, leaves and other debris. If your air-cooled condenser must operate in unusually dusty locations, cleaning should be scheduled as often as conditions dictate. WARNING: BE SURE THAT THE MAIN DISCONNECT SWITCH IS IN THE OFF POSITION BEFORE ANY CLEANING OR MAINTENANCE OF THE CONDENSERS. 8.2 ELECTRICAL AND PIPING CONNECTIONS All electrical connections should be periodically checked to be sure they are tight. Loose connections contribute to low voltage conditions which can cause motor failure. Refrigerant connections should be inspected to insure that they have not loosened. Whenever it is necessary to add refrigerant, a careful leak check of all refrigerant connections should be made. 8.3 CRANKCASE LUBRICATION As indicated under the operational check-out procedures, the oil level in the motor compressor crankcase should be at the center of the sight glass as all times. If the oil level is low, more oil should be added to bring the level up to the center of the sight glass. The expansion valve adjustment and the size of the risers and traps should be checked to locate the cause of the oil migration to correct it. The quality of the compressor oil can be checked by using an oil sample. Visual examination for the compressor oil can disclose the condition of the system. Acid test is highly recommended to measure the extent of contamination in the system. Dirty, discolored oil indicates one of the following: A. Contaminations such as moisture, air, etc., trapped in the system. B. Excessive pressure drop of improper control settings allows motor compressors to operate at a dangerously low suction pressure. This may cause motor compressor overheating and oil discoloration. KAIRAK REMOTE RACK SYSTEM PAGE 27
If this situation occurs and oil discoloration is not too dark, the installation of a new liquid line filter/drier may be enough to remove contamination and clear the oil. If the discoloration is severe, the oil should be replaced and a new liquid filter/drier installed as many times as necessary to eliminate the contamination. After the oil is replaced, the system controls should be readjusted. 8.4 MAINTENANCE CHECKLIST (at the rack) A. Condenser check to insure it is clean. Adjust cleaning schedule if necessary. B. Compressor Excessive noise: check mounting grommets, tighten if loose; check for excessive ice buildup at the suction side and signs of liquid slogging back to it; make sure compressor is not short cycling. C. Pressure reading high side and low side. Check cut in and cut out; adjust if necessary. D. Sight glasses check for flashing or bubbling. Add refrigerant to clear it. E. Check for oil residue or stain around entire unit. Oil residue or stain should be an indication of a refrigerant leak. F. Condenser fan motor rotation check for any sign of excessive vibration or loud noise. G. Electrical components check that all timers are properly set. Check all electrical connections and contacts for signs of burns. 8.5 EVAPORATOR COIL Evaporator coil should be checked at least once a month for proper defrosting to maintain amount and pattern of frosting. It is dependent on the temperature of the room, the type of product being stored, how often new product is brought into the room and the percentage of time the door to the room is open. Also, if the coil is not defrosting completely, check for faulty defrost heaters. Under normal usage, maintenance should cover the following items at least once every six months: A. Tighten all electrical connections. B. Tighten fan set screws. C. Clean the coil surface. PAGE 28 KAIRAK REMOTE RACK SYSTEM
D. Clean the fan blades. E. Check the operation of the control system. F. Clean the drain pan and check for proper drainage. G. Check the drain line heaters. 8.6 HEATER REPLACEMENT IN LOW TEMP EVAPORATOR COIL A. Make sure the electrical power to the heaters is turned off. B. Disconnect heater leads on both ends of the heater to be removed. C. Remove the sheet metal screws holding the heater retainer to the heater plate on the electrical connection end of the unit. D. Pull the heater(s) to be replaced out of the tube holes in the coil. It is necessary to lower the drain pan to remove the bottom heater. E. Replacement coil heaters are received coiled in a two foot diameter. Before inserting the heater in the coil, uncoil about one foot of the straight end to make it easier to insert the heater into the tube hole. F. Insert end of the heater into tube hole and uncoil it while pushing it through the coil. G. Attach tube clamp and retaining bracket to new heater just before rubber boot. Push heater in until bracket meets the header plate. Fasten bracket to the header plate to prevent heater creep. H. Reconnect the heater leads as shown on the wiring diagram. KAIRAK REMOTE RACK SYSTEM PAGE 29
9. TROUBLESHOOTING SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Motor line open. Fuse blown. Tripped overload. Close start or disconnect switch. Replace fuse. See Compressor will not start Compressor does not run Control contacts are dirty or jammed in open position. Frozen compressor or motor bearings. Control in off position because of cold location. Repair or replace. Repair or replace. Use thermostatic control or move control to warmer location. Defective starting component. (Single phase compressor only) Locate and replace. Unit short cycles Control differential set too closely. Discharge valve leaking. Motor compressor overload. Refrigerant shortage. Refrigerant overcharged. Widen differential. Correct condition. Check for high head pressure, tight bearings, seized, pistons, clogged air cooled condenser. Repair leak and recharge. Purge System. PAGE 30 KAIRAK REMOTE RACK SYSTEM
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Cycling on high pressure. Check water supply, dirty condenser or defective fan. Compressor will not start hums intermittently (cycling on overload). Improperly wired. Low line voltage. Relay contacts not closing. Open circuit in starting winding. Stator winding grounded. High discharge pressure. Tight compressor. Check wiring against diagram. Check main line voltage and determine location of voltage and drops. Check by operating manually. Replace relay if defective. Check stator leads. If leads are ok, replace stator. Check stator leads. If leads are ok, replace stator. Eliminate cause of excessive pressure. Make sure discharge shut-off valve is open. Check oil level. Correct binding. Refrigerant shortage Repair leak and re-charge. Unit operates long or continuously. Control contacts sticking in closed position. Dirty condenser. Air in system. Compressor inefficient. Clean points or replace control. Clean condenser. Purge system to remove air. Check valves and piston. KAIRAK REMOTE RACK SYSTEM PAGE 31
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Improper wiring. Check wiring to schematic. Correct if necessary. Refrigerant shortage. Repair leak and recharge. Control set too high. Control wiring loose. Reset control. Check wiring to control. Fixture temperature too high. Expansion valve or strainer plugged. Compressor inefficient. Expansion valve set too high. Iced or dirty coil. Unit too small. Clogged or small gas lines. Oil logged system. Clean or replace. Check valves and pistons. Lower settings. Defrost or clean. Add unit or replace. Clear clog. Increase line size. Remove excess oil. Check Refrigerant. Charge if needed. Head pressure too high. Refrigerant overcharge. Air in system. Dirty air-cooled condenser. Purge system. Purge system. Clean area around air-cooled condenser and inspect for airborne dirt source. PAGE 32 KAIRAK REMOTE RACK SYSTEM
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Insufficient water supply. Recirculating cooling air. High side restriction. Check water isolation valves. Adjust water pressure regulator valve. Inspect chiller. Seal off unit from other machines and provide intake isolated from air outlet. Remove blockage. Head pressure control valve set wrong. Readjust. Refrigerant shortage. Repair leak and recharge. Compressor suction or discharge valves inefficient. Clean or replace leaky valve plates or replace compressor. Head pressure too low. Cold ambient or cold water. Check condenser fan motors cycle controls and adjust. Check head pressure valve and adjust or replace. Adjust water pressure regulator valve. Head pressure control valve set wrong or no head pressure valve installed. Readjust or install a head pressure control valve. Noisy unit. Insufficient compressor oil. Tubing rattles. Mounting loose. Repair leak and recharge. Bend tubes away from contact and secure. Tighten. KAIRAK REMOTE RACK SYSTEM PAGE 33
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Oil slugging or refrigerant flood back. Adjust oil level or refrigerant change. Check expansion valve for leak or oversized orifice. Adjust the superheat Unbalanced fan or defective fan motor. Replace bent or broken fan blades. Check motor bearings. Tighten motor holder or replace. Replace motor. Short of refrigerant. Gas/oil ratio low. Repair leak and recharge. Add oil to compressor to reach half sight glass level. Compressor loses oil. Plugged expansion valve or strainer. Oil trapped in lines. Short cycling. Superheat too high at compressor suction. Clean or replace. Drain tubing toward compressor. See Unit short cycles above. Change location of expansion valve bulb or adjust valve to return wet gas to compressor. Improper installation and piping practice. Check piping sizes and methods and confirm suction lines are sloped toward compressor. Check for oil traps on the risers. Correct piping. Frosted or sweating suction line. Expansion valve admitting excess refrigerant. Adjust expansion valve. PAGE 34 KAIRAK REMOTE RACK SYSTEM
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Poor or improper insulation. Repair, or replace with thicker insulation. Hot liquid line. Shortage of refrigerant. Expansion valve open too wide. Refrigerant overcharge. Insufficient condensing. Repair leak and recharge. Adjust expansion valve. Purge system. Check if the condenser is dirty, fan motor operational, sufficient water supply. Frosted liquid line. Receiver shut-off valve partially closed or restricted. Clogged dehydrator or restricted. Open valve or remove. Replace clogged part. Unit on vacuum Ice plugging expansion valve. Plugged expansion valve. Defective pressure switch. Apply hot wet cloth to expansion valve. If suction pressure increases, there is moisture in the system and the filter drier should be replaced. Clean strainer or replace expansion valve. If the pressure switch is stuck closed, replace. If the switch is set too low adjust to proper setting, above 5 psi. Compressor will not Defective capacity control. Replace. KAIRAK REMOTE RACK SYSTEM PAGE 35
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION unload or load up. Unloader mechanism Replace. defective. Faulty thermostat stage or broken capillary tube. Replace. Stages not set for application. Replace. Clogged suction oil strainer. Excessive liquid in crankcase. Oil pressure gauge defective. Clean strainer. Check crankcase heater. Reset expansion valve for higher superheat. Check liquid line solenoid valve operation. Repair or replace. Keep valve closed except when taking reading. Little or no oil pressure. Low oil pressure safety switch defective. Worn oil pump. Replace. Replace. Oil pump reversing gear stuck in wrong position. Worn bearing. Low oil level. Loose fitting on oil lines. Reverse direction of compressor rotation. Replace compressor. Add oil. Check and tighten system. Pump housing gasket leaks. Replace gasket. PAGE 36 KAIRAK REMOTE RACK SYSTEM
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Flooding of refrigerant into crankcase. Adjust thermal expansion valve. Low voltage during high load conditions. Check supply voltage for excessive line drop. Motor overload relays or circuit breaker open. Defective or grounded wiring in motor or power circuits. Loose power wiring. High condensing temperature. Power line fault causing unbalanced voltage. Replace compressor motor. Check all connections and tighten. See corrective steps for high discharge pressure. Check supply voltage. Notify power company. Do not start until fault is corrected. High ambient temperature around the overload relay. Provide ventilation to reduce heat. Failure of second starter to pull in on part winding system. Repair or replace starter or time delay mechanism. Compressor thermal protector switch open. Operating beyond design conditions. Discharge valve partially shut. Add facilities so that conditions are within allowance limits. Open valve. KAIRAK REMOTE RACK SYSTEM PAGE 37
SYMPTOM PROBABLE CAUSE RECOMMENDED ACTION Blown valve gasket. Replace gasket. Freeze protection opens. Thermostat set too low. Low water flow. Low suction pressure. Reset to 40 F or above. Adjust GPM. See Low suction pressure PAGE 38 KAIRAK REMOTE RACK SYSTEM
10. TABLES AND CHARTS 10.1 TEMPERATURE PRESSURE CHART Temp (F) R404A Temp (F) R404A -50 0.6 55 114.7-45 2.7 60 125.3-40 5.0 65 136.6-35 7.6 70 148.6-30 10.4 75 161.2-25 13.4 80 174.6-20 16.8 85 188.8-15 20.5 90 203.7-10 24.5 95 219.4-5 28.8 100 235.9 0 33.5 105 253.4 5 38.6 110 271.7 10 44.0 115 290.9 15 49.9 120 311.1 20 56.2 125 332.3 25 63.0 130 354.5 30 70.3 135 377.8 35 78.1 140 402.2 40 86.4 145 427.7 45 95.2 150 454.4 50 104.7 KAIRAK REMOTE RACK SYSTEM PAGE 39
10.2 LINE SIZING FOR REFRIGERATION SYSTEMS The following tables indicate liquid lines and suction lines for all condensing units. When determining the refrigerant line length, be sure to add an allowance for fittings, (see table 2 below). Total equivalent length of refrigerant lines is the sum of the actual linear footage and the allowance for fittings. Table 1: Pressure loss Pressure loss of liquid refrigerant in liquid line risers. (Expressed in pressure drop, PSIG and subcooling loss, F). LIQUID LINE RISE IN FEET 10' 15' 20' 25' 30' 40' 50' 75' 100' REFRIGERANT PSIG F PSIG F PSIG F PSIG F PSIG F PSIG F PSIG F PSIG F PSIG F R404A 4.1 1.1 6.1 1.6 8.2 2.1 10.2 2.7 12.2 3.3 16.3 4.1 20.4 5.6 30.6 8.3 40.8 11.8 Table 2: Equivalent Feet of Pipe Due to Valve and Fitting Friction Copper Tuber, OD, Type "L" 1/2 5/8 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 5 1/8 6 1/8 Globe Valve (Open) 14 16 22 28 36 42 57 69 83 99 118 138 168 Angle Valve (Open) 7 9 12 15 18 21 28 34 42 49 57 70 83 90 Turn Through Tee 3 4 5 6 8 9 12 14 17 20 22 28 34 Tee (Straight Through) or Sweep Below 0.75 1 1.5 2 2.5 3 3.5 4 5 6 7 9 11 90 Elbows or Reducing Tee (Straight Through) 1 2 2 3 4 4 5 7 6 10 12 14 16 PAGE 40 KAIRAK REMOTE RACK SYSTEM
Table 3: Weight Of Refrigerant Weight of refrigerant for copper lines during operation. (Pounds per 100 lineal feet of type L tubing) Line Size O.D. in Inches Refrigerant Liquid Line Hot Gas Line Suction Line at Suction Temperature -40 F -20 F 0 F +20 F +40 F 3/8 404A 3.4 0.31 0.03 0.04 0.06 0.09 0.13 1/2 404A 6.4 0.58 0.04 0.07 0.13 0.16 0.24 5/8 404A 10.3 0.93 0.07 0.11 0.17 0.25 0.35 7/8 404A 21.2 1.92 0.15 0.23 0.37 0.51 0.72 1-1/8 404A 36.1 3.27 0.26 0.39 0.63 0.86 1.24 1-3/8 404A 55 4.98 0.4 0.58 0.95 1.32 1.87 1-5/8 404A 78 7.07 0.56 0.82 1.35 1.86 2.64 2-1/8 404A 134 12.25 0.98 1.43 2.35 3.23 4.58 2-5/8 404A 209 18.92 1.51 2.21 3.62 5 7.07 3-1/8 404A 298 27.05 2.16 3.15 5.17 7.14 9.95 3-5/8 404A 403 36.5 2.92 4.25 6.97 19.65 13.67 4-1/8 404A 526 47.57 3.8 5.55 9.09 12.58 17.8 KAIRAK REMOTE RACK SYSTEM PAGE 41