Unit Operation - Trane CXAJ series Installation, Operation And Maintenance Manual

Modular air-cooled chiller (heat pump) unit
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Unit Operation

Start Steps
• Power on the unit, press MODE button on the Single Unit Controller to select cooling or
• When the unit operates for over 30 minutes and the system steadily operates, inspect the
• Make sure all temperature sensors are installed at the correct position, and the capillary
• Inspect the unit and remove the wastes, the tools and the parts. Fix all shell plate metal parts
Long-term Shutdown
• If this system is not used for a long time, the followings shall be done before shutdown:
heating after 120 seconds, and then press ON/OFF button on the Single Unit Controller to
start the unit.
following items to ensure the normal operation of the unit:
1. Inspect whether the water flow and water pressure readings of the unit are stable and
within the normal range.
2. Test the high and low pressures of the unit. During the normal operation, the low pressure
shall be 85-145 psig (0.586-1.0 MPa), and the high pressure shall be 290-500 psig (2.0-3.45
MPa).
3. Inspect the current reading of the compressor.
4. Inspect the power supply.
5. Measure the system superheat degree.
In ARI conditions (water inlet temperature of 12.2 ℃ , water outlet temperature of 6.7 ℃ ,
ambient temperature of 35 ℃ ), the normal system superheat of each circuit is 5-8 ℃ . The
superheat measured on any circuit is beyond this range, the superheat setting on the
expansion valve shall be regulated to obtain a proper reading. Wait for 15 to 30 minutes to
make the new set value stable after each adjustment of expansion valve.
6. Measure the system sub-cooling degree.
In ARI conditions, the normal system sub-cooling degree of each circuit is 5-10 ℃ . If the
sub-cooling degree measured on any circuit is beyond this range, necessary adjustment
shall be made after the inspection of circuit superheat. If the superheat is normal but the
sub-cooling degree is abnormal, please contact the professional maintenance personnel.
7. If the system leakage is found, the leakage point shall be found out to repair, and then
the gaseous refrigerant shall be charged into the circuit. When the unit operates, the
refrigerant is charged from the low pressure pipe till the operating pressure is normal. If
the operating pressure is low, and the sub-cooling degree is low, it will indicate that the
refrigerant is insufficient.
8. If the operating pressure shows that the refrigerant is excessive, the refrigerant shall be
recycled slowly at the liquid pipe (to minimize the loss of refrigerant oil as far as possible).
9. The start and stop unit below 4 times in an hour.
tubes of the temperature sensors must be firmly fixed in order to avoid vibration and
abrasion.
including the control panel and the compressor access plate, and install all screws to the
original places.
1. Inspect whether the refrigerant pipe leaks or not. If any, be sure to repair it.
2. Maintain the water pump and the air conditioning equipment as recommended by the
manufacturer.
3. Empty the circulating water in the system, unscrew the water drainage opening in the
water supply and return circuit, disassemble the side panel of the unit, unscrew the water
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