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Twist TwistAero PCA090480WH Maintenance Manual

Air conditioning unit 90 nominal refrigeration tons
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Summary of Contents for Twist TwistAero PCA090480WH

  • Page 1 Maintenance...

  • Page 2: Table Of Contents

    Refrigerant Leaks ............2 - 3....43 Brazing Refrigerant Lines ..........2 - 3....45 Pressure Testing ............2 - 3....46 Evacuation..............2 - 3....46 Charging................ 2 - 3....47 March 2013 Table of Contents Proprietary/Confidential Page 31 © 2013 Twist, Inc.
  • Page 3 Cleaning and Painting Filters ..................2 - 9....59 Condensers ................2 - 9....59 Evaporators and Ducts............. 2 - 9....59 Painting ..................2 - 9....60 Table of Contents March 2013 Page 32 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 4: Introduction To Servicing

    Section 1: Introduction to Servicing Owner’s Responsibility Ownership of PCA units supplied by Twist, Inc. imposes a duty upon the Owner to maintain the integrity of the equipment. The objective of periodic maintenance is to ensure that the units are in the same condition and configuration as originally supplied by Twist, Inc.

  • Page 5: Operator Daily Inspection

    CHAPTER 2 SERVICE Section 1: Introduction to Servicing General Considerations Only trained personnel should work on the Twist Pre-Conditioned Air unit. Avoid hurried or careless workmanship. Schedule work from start to finish without interruption to insure no steps are overlooked.

  • Page 6: Safety Precautions

    The power then can be turned on. Use extreme caution when working on the unit with power ON. March 2013 Proprietary/Confidential Page 35 © 2013 Twist, Inc.

  • Page 7: Refrigerant Precautions

    Burns - Body tissue may be damaged by freezing. Avoid contact of liquid refrigerant with the bare skin since damages similar to burns may result. March 2013 Page 36 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 8: Refrigeration Basics And Service

    The refrigerant vapor leaving the evaporator coil travels through the suction line to the compressor inlet. The refrigeration process starts over again and continues as long as the compressor is in operation. March 2013 Proprietary/Confidential Page 37 © 2013 Twist, Inc.

  • Page 9: Fundamentals

    Thoroughly evacuate the system after any exposure to the atmosphere.  Any time the system is to be opened, introduce a slightly positive pressure to prevent air from rushing into the lines. March 2013 Page 38 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 10: Oil Refrigerant Mixture

    Failure to do so can severely damage the compressor, creating added work and considerable expense. March 2013 Proprietary/Confidential Page 39 © 2013 Twist, Inc.

  • Page 11: Servicing System And Charging

    Repeat the same procedure with the low-pressure valve. Close the valves on the manifold and crack the low-pressure service valve, connecting the manifold to the system, making it ready for use. March 2013 Page 40 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 12: Service Valves

    Always use a refrigerant recovery system. Check the instructions on the recovery system for proper operation and follow the latest EPA Regulations for refrigerant disposal and records. Check the oil level in the compressor crankcase after the refrigerant is removed. March 2013 Proprietary/Confidential Page 41 © 2013 Twist, Inc.

  • Page 13: Adding Or Removing Oil

    (A little oil will keep the stopper from sticking.) The function of the stopper is to stabilize the pump and keep out contamination. March 2013 Page 42 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 14: Dealing With Non-Condensable

    Refrigeration systems must be absolutely air tight for two reasons: First, any leakage will result in loss of the refrigerant charge. Second, leaks allow air and moisture to enter the system, causing damage to components. March 2013 Proprietary/Confidential Page 43 © 2013 Twist, Inc.
  • Page 15 Despite its simplicity, the soap bubble method can be extremely helpful in pinpointing a leak that is difficult to locate. March 2013 Page 44 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 16: Brazing Refrigerant Lines

    This oxide can be extremely harmful to a refrigerating system. To prevent its formation, sweep an inert gas such as dry nitrogen through the line at low pressure during the brazing operation. Always March 2013 Proprietary/Confidential Page 45 © 2013 Twist, Inc.

  • Page 17: Pressure Testing

    Connect the “High” and “Low” pressure connections on the gauge manifold securely to the service valves on the “High” and “Low” pressure sides of the system respectively and close the valves on the gauge manifold. March 2013 Page 46 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 18: Charging

    To maintain cylinder pressure and expedite charging, warm the cylinder by placing it in warm water or by using a heat lamp. Do not apply heat with a torch. March 2013 Proprietary/Confidential Page 47 © 2013 Twist, Inc.
  • Page 19 While the sight glass is a valuable aid in determining the proper charge, the system performance must be carefully analyzed before placing full reliance on it as a positive indicator of the system charge. March 2013 Page 48 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 20: Introduction To Preventive Maintenance Checklists

    Introduction The following checklists cover all points to be inspected and/or adjusted. A space is provided for the maintenance person to initial. Twist, Inc. suggests those responsible for unit upkeep make copies of these checklists, give them to the maintenance personnel, and after the service work is completed, bind these checklists into a history of the work performed.
  • Page 21 MODEL PCA090480WH CHAPTER 2 SERVICE Section 4: Introduction to Preventive Maintenance Checklists This page left blank intentionally. March 2013 Page 50 Proprietary/Confidential © 2013 Twist, Inc...

  • Page 22: Preventive Maintenance Quarterly Checklist

    7. Check refrigerant lines and flare nuts. Check lines for wear and leakage and repair accordingly. 8. Visually check air passageways inside the unit for obstruction that may block airflow. Clean accordingly. March 2013 2 - 5 Proprietary/Confidential Page 51 © 2013 Twist, Inc...
  • Page 23 14. Check general condition of fan blade assembly and replace if necessary. 15. Check all magnetic contactors for abnormal wear. Repair or replace as needed. 16. Confirm proper operations of the VFD. 2 - 5 March 2013 Page 52 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 24: Preventive Maintenance Semi- Annual Checklist

    1. Check all motors for free rotation and grease all zerk fittings with one-half pump of the grease gun (1/2”). Do not over- lube. 2. Inspect all components in main control panel and repair/replace as necessary. March 2013 2 - 6 Proprietary/Confidential Page 53 © 2013 Twist, Inc.
  • Page 25 MODEL PCA090480WH CHAPTER 2 SERVICE Section 6: Preventive Maintenance Semi-Annual Checklist This page left blank intentionally. 2 - 6 March 2013 Page 54 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 26: Preventive Maintenance Seasonal Checklist

    3. Clean condenser coil. Wash with mild soapy water. Clean more often if environmental conditions dictates. 4. Clean evaporator coil with mild soapy water. Clean more often if environmental conditions dictates. March 2013 2 -7 Proprietary/Confidential Page 55 © 2013 Twist, Inc.
  • Page 27 MODEL PCA090480WH CHAPTER 2 SERVICE Section 7: Preventative Maintenance Seasonal Checklist This page left blank intentionally. 2 - 7 March 2013 Page 56 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 28: Adjustments

    Subtract the two temperatures obtained in 1 and 3 - the difference is superheat. To change the superheat setting: March 2013 Proprietary/Confidential Page 57 © 2013 Twist, Inc.

  • Page 29: Hot Gas By Pass Valve Adjustment

    Adjust the airflow to get the suction pressure higher or lower to test the hot gas valve setting. When service is complete, remove the service gauge manifold connection and cap the Schrader valves. Replace the cap on the hot gas valve. March 2013 Page 58 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 30: Cleaning And Painting

    Continue to operate the unit for another fifteen minutes after the water spray has stopped to dry the unit. Turn unit off and reset the circuit breakers. Clean the air filters and re-install. March 2013 Proprietary/Confidential Page 59 © 2013 Twist, Inc.

  • Page 31: Painting

    SERVICE Section 9: Cleaning and Painting Painting Specifications All aluminum surface preparation and painting of Twist, Inc.’s equipment is powder coated. All steel services are cleaned, phosphate, primed, and painted with a high zinc content paint. Frequency If the paint surface of your PCA unit has been damaged or is showing signs of rust, immediate repair and/or field touch-up painting is required.
  • Page 32 Before applying the finish coat, carefully mix the proper catalyst with the finish coat base per the instructions on the paint containers. The final application of the finish coat may be applied with a brush, a paint sprayer, or a roller. Twist, Inc. recommends the topcoat be sprayer applied. CAUTION: AFTER THE PRIMER OR FINISH COAT IS MIXED, THE POT LIFE OF THE MIXED PAINT WILL BE LIMITED.
  • Page 33 MODEL PCA090480WH CHAPTER 2 SERVICE Section 9: Cleaning and Painting This page left blank. March 2013 Page 62 Proprietary/Confidential © 2013 Twist, Inc.
  • Page 34 Trouble XI - Refrigerant suction pressure too low ....3 - 4....81 Trouble XII - Refrigerant discharge pressure too high....3 - 4....82 Trouble XIII - Refrigerant discharge pressure too low ....3 - 4....83 March 2013 Table of Contents Proprietary/Confidential Page 63 © 2013 Twist, Inc.
  • Page 35 Smoke Detector ............... 3 - 6....96 Phase Monitor ................3 - 6....96 Heating Coils ................3 - 6....96 Cooling Compressors............... 3 - 6 ....96 Table of Contents March 2013 Page 64 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 36: Introduction

    The tables in this section outline the problems, likely causes, and remedies. As it is impossible to foresee all breakdowns, this chapter should not be expected to provide answers to every failure. March 2013 Proprietary/Confidential Page 65 © 2013 Twist, Inc.
  • Page 37 MODEL PCA090480WH CHAPTER 3 TROUBLESHOOTING Section 1: Guide to Repair This page left blank intentionally. March 2013 Page 66 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 38: 2: Troubleshooting Basic System

    Check for balance voltage on all three legs. The phase monitor will stop the unit if the voltage is not balanced within 8%. March 2013 3 - 2 Proprietary/Confidential Page 67 © 2013 Twist, Inc.

  • Page 39: Trouble Ii: Excessive Power Draw

    Single phasing of motors due to Repair connections at all connection loss of one phase in the power points include locations such as supply or mechanical connection magnetic contactors. of the wiring 3 - 2 March 2013 Page 68 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 40: Trouble Iii: Abnormally Low Power Draw

    Check for proper airflow on supply side of system unit. Check ambient air temperature to verify if unit is operating in proper range. Excessive voltage Check power source. March 2013 3 - 2 Proprietary/Confidential Page 69 © 2013 Twist, Inc.
  • Page 41 MODEL PCA045480WH CHAPTER 3 TROUBLESHOOTING Section 2: Troubleshooting Basic System This page left blank. 3 - 2 March 2013 Page 70 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 42: 3: Troubleshooting Airflow System

    Evaporator coil frosted or iced-up See “Evaporator Coil(s) Freeze Up” Chapter 3-5 page 6. Leaking unit-to-duct and/or duct-to- Check duct connections for loose or aircraft connections poor-fitting joints and tighten or repair as necessary. March 2013 Proprietary/Confidential Page 71 © 2013 Twist, Inc.

  • Page 43: Trouble Ii - Abnormally Noisy Blower

    Remove wheel, and balance or replace it as required. Blower wheel loose on shaft Adjust and retighten blower wheel as necessary. Blower wheel hitting or rubbing Readjust blower inlet cone or wheel on inlet cone shaft. March 2013 Page 72 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 44: 4: Troubleshooting Refrigeration System

    Verify that magnetic contact is in good working order and that all phases of power exist at both line and load sides. Check compressor to ensure that motor is not grounded to casing. March 2013 Proprietary/Confidential Page 73 © 2013 Twist, Inc.

  • Page 45: Trouble Ii - Compressor Short Cycles Or Shuts Off After A

    High” Chapter 3-5 page 10. open Faulty compressor motor Replace compressor. Low supply airflow Check for kinks in the duct and clean air filters. See Section 3-3 Trouble #1 for additional information. March 2013 Page 74 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 46: Trouble Iii: Insufficient Cooling

    Verify pressures system operations. 12. Controller not operating properly 1. Check temperature settings on device and correct or replace component as necessary. March 2013 Proprietary/Confidential Page 75 © 2013 Twist, Inc.

  • Page 47: Trouble Iv: Excessive Compressor Vibration

    (Flooding) If a compressor should experience severe refrigerant flooding, it will make a loud "rattling" sound. This is normal because the separation of the scrolls allows the liquid refrigerant to pass through the compressor without damage. March 2013 Page 76 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 48: Trouble Vi: Flutter Noise When Compressor Stops

    Provide good contact between remote bulb and suction line. (See Chapter 3-6 page 4.) Liquid flooding back to compressor Readjust superheat setting or check remote bulb contact. (See Chapter 2-8 page 1.) March 2013 Proprietary/Confidential Page 77 © 2013 Twist, Inc.

  • Page 49: Trouble Viii: Evaporator Coil(S) Freeze Up

    Suction pressure too low See Trouble XI Chapter 3-5 page 9 of this manual. Also refer to Chapter 2 Section 2-8 for EPR Valve information. March 2013 Page 78 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 50: Trouble Ix: Refrigerant Flood Back To Compressor

    See Chapter 2-8 page 1 of this expansion valve manual. Restricted or plugged Expansion Reclaim system, repair/replace Valve equalizer line equalizer line, and re-charge. Low supply airflow See Trouble II Chapter 3-3 page 1 of this manual. March 2013 Proprietary/Confidential Page 79 © 2013 Twist, Inc.

  • Page 51: Trouble X: Refrigerant Suction Pressure Too High

    (See Chapter 2-8 page 1 and Chapter 3-6 page 4.) Expansion valve stuck open position Repair or replace valve. (See Chapter 3-6 page 4.) March 2013 Page 80 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 52: Trouble Xi - Refrigerant Suction Pressure Too Low

    If pressures are the same, the valve is OK, and the crankcase pressure is lower, the screen is plugged. Replace compressor. March 2013 Proprietary/Confidential Page 81 © 2013 Twist, Inc.

  • Page 53: Trouble Xii - Refrigerant Discharge Pressure Too High

    Unit will automatically shut-down condition compressor. High Pressure Switch is a automatic reset switch. Restriction in discharge line to Reclaim refrigerant and remove condenser restriction in line. Re-charge system and test. March 2013 Page 82 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 54: Trouble Xiii: Refrigerant Discharge Pressure Too Low

    Reclaim system and check for leaks. Re-charge system and test. Compressor malfunction Replace compressor. Ambient temperature too low Do not operate unit. Compressor operating backward Change phase rotation to ABC. (See Chapter 3-6 page 7.) March 2013 Proprietary/Confidential Page 83 © 2013 Twist, Inc.
  • Page 55 MODEL PCA090480WH CHAPTER 3 TROUBLESHOOTING Section 4: Troubleshooting Refrigeration System This page left blank. March 2013 Page 84 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 56: Helpful Troubleshooting Information

    10 lb. above the saturation pressure corresponding to the surrounding air temperature. See the Appendix for R-407C pressure/temperature relationship. March 2013 Proprietary/Confidential Page 85 © 2013 Twist, Inc.

  • Page 57: Clogged Filter-Drier

    Check if the solenoid valve upstream of the valve is opened. The solenoid valve is controlled by the ALC output. Hot Gas By-pass Valve Adjustment Procedure This procedure is more easily performed when ambient air temperature is below 85 degrees F. March 2013 Page 86 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 58: Hot Gas By-Pass Valve Adjustment Procedures

    To test for an inoperative power element: Stop compressor. Remove remote bulb from contact with suction line. Place bulb in ice water. Start compressor. Remove bulb from ice water and warm in hand. At the same March 2013 Proprietary/Confidential Page 87 © 2013 Twist, Inc.

  • Page 59: Valve Stuck In Open Position

    This is a common source of trouble on expansion valves. Since the valve is the first cold spot in the system, moisture will freeze and block the valve open, closed, or in any position in between. (See “B” and “C” above.) March 2013 Page 88 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 60: Expansion Valve Field Disassembly/Re-Assembly

    10" adjustable wrenches, to seal the metal-to-metal knife-edge joint. The sealing surfaces should be free of any foreign material or nicks that might prevent a leak-tight joint. March 2013 Proprietary/Confidential Page 89 © 2013 Twist, Inc.

  • Page 61: Compressor Electrical Phase Rotation

    The suction pressure should drop, and the discharge pressure should rise. If the compressor is phased incorrectly, it will exhibit the following symptoms: March 2013 Page 90 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 62: Compressor Operating In A Vacuum

    400-500°F, which causes the orbiting scroll to rub on the fixed scroll, resulting in a compressor failure. The failure will start to initiate in 1-2 minutes of operation and will only deteriorate further after the failure starts. March 2013 Proprietary/Confidential Page 91 © 2013 Twist, Inc.

  • Page 63: Compressor Motor Megging

    As a result, the condensing pressure will rise. In extreme cases, it may rise to a point where the high-pressure cutout will stop the compressor. March 2013 Page 92 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 64: Troubleshooting Direct Digital Controller (Ddc)

    2 flashes in sync, Module is configured for a then pause. different baud rate than the rest of the network segment. 2 flashes / second 3 flashes, then off Module has been formatted March 2013 Proprietary/Confidential Page 93 © 2013 Twist, Inc.
  • Page 65 Narrow Body mode. Depending on which pushbutton is depressed the ALC will bring the unit up in the proper mode, determining by ambient temperature the correct running mode for the present conditions. March 2013 Page 94 Proprietary/Confidential © 2013 Twist, Inc.

  • Page 66: Checking Controller Inputs

    The next most likely cause of a problem is that the thermal overloads are tripped. Reset the overloads and check the system again. If the overloads trip on a regular basis, check the amperage of the motor. Check the settings of March 2013 Proprietary/Confidential Page 95 © 2013 Twist, Inc.

  • Page 67: Control Voltage

    If the ALC controller is calling for cooling but the compressors don’t seem to operate, check the high and low refrigerant pressure limit switches and the high compressor temperature limit switch. March 2013 Page 96 Proprietary/Confidential © 2013 Twist, Inc.
  • Page 68 Removal for Overhaul .............. 4 - 1....99 Replacement Parts..............4 - 1....99 Shipping Procedures Shipping Procedure..............4 – 2 .... 101 Storage Procedures Storage Procedure ..............4 - 3..... 103 March 2013 Table of Contents Proprietary/Confidential Page 97 © 2013 Twist, Inc.
  • Page 69 MODEL PCA090480WH CHAPTER 4 REMOVAL, SHIPPING, AND STORAGE Table of Contents This page left blank intentionally. Table of Contents March 2013 Page 98 Proprietary/Confidential © 2013 Twist, Inc.
  • Page 70 Manufacture Refrigerant DuPont Refrigerant Oil BVC32 Polyvinylether Coil Cleaner Nu-Brite Starter Duct 20’ Section Twist Flat Duct 20’ Section Twist Reducer 14” to 8” Flat Twist Aircraft Adapter Twist March 2013 4 -1 Proprietary/Confidential Page 99 © 2013 Twist, Inc.
  • Page 71 I/O FLEX 6126 Controller, Flex I/O6126 I/O FLEX 8160 Expansion Board Flex I/O8160 GPRM-B4C05C-3 Relay, 4PDT, 5A, 24 VAC, LED,STOP C3 Controls 3UG4513-1BR20 Relay, 3PH Line Monitoring 400VAC Siemens 4 -1 March 2013 Page 100 Proprietary/Confidential © 2032 Twist, Inc.

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