Thermo King T-1000R, Maintenance Manual

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Refrigeration Maintenance 10-29
CONDENSER CHECK VALVE TEST (SINGLE TEMPERATURE UNITS ONLY)
The condenser check valve prevents refrigerant from moving into the condenser when the unit is in heat. A unit with a leaking
condenser check valve will have good heating capacity when it first goes into the heat mode. But, it will gradually lose heating
capacity as refrigerant moves into the condenser. This problem is more noticeable at lower ambient temperatures. Use the
following procedure to test the condenser check valve.
1. Attach a gauge manifold to the suction service valve and the discharge service valve. Attach another low pressure gauge to
the suction access port located in the suction line near the accumulator inlet. Attach a high pressure gauge to the service port
on the receiver tank outlet valve. A low loss fitting must be used on the hose connected to the suction access port.
2. Operate the unit in low speed cool until the system pressures stabilize.
3. Front seat the receiver tank outlet valve and allow the low side to pump down to 0 to 5 in. Hg vacuum (0 to -17 kPa).
4. Turn the unit Off.
5. Front seat the suction service valve to isolate the low side while it is still in a vacuum.
6. Watch the low pressure gauge attached to the suction access port. The low side pressure should not rise. If it does, there could
be a leak through the hot gas solenoid or the receiver tank pressure check valve (or both).
7. Use the Mechanics/Premium HMI Control Panel to enter the Interface Board Test Mode. Refer to the appropriate
Microprocessor Diagnostic Manual for specific information about the Interface Board Test Mode.
8. From the Interface Board Test Mode select Hot Gas Solenoid.
9. Energize the hot gas solenoid with the Interface Board Test Mode. The discharge pressure and the low side pressure should
equalize when the hot gas solenoid is energized.
10. De-energize the hot gas solenoid with the Interface Board Test Mode when the discharge pressure and the low side pressure
have equalized.
11. Watch the gauges attached to the discharge service port and the receiver tank. The discharge pressure should not rise and the
receiver tank pressure should not fall. If the discharge pressure rises, the condenser check valve is probably leaking.
12. Back seat the receiver tank outlet valve and suction service valve. Perform a “Refrigerant Gauge Removal” procedure.
CONDENSER CHECK VALVE AND PURGE CHECK VALVE TEST (T-500R/T-DAIRY)
1. Attach a gauge manifold to the suction service valve and the discharge service valve. Attach another low pressure gauge to
the suction access port located in the suction line near the accumulator inlet. Attach a high pressure gauge to the service port
on the receiver tank outlet valve. A low loss fitting must be used on the hose connected to the suction access port.
2. Operate the unit in low speed cool until the system pressures stabilize.
3. Front seat the receiver tank outlet valve and allow the low side to pump down to 0 to 5 in. Hg vacuum (0 to -17 kPa).
4. Turn the unit Off.
5. Front seat the suction service valve to isolate the low side while it is still in a vacuum.
6. Watch the low pressure gauge attached to the suction access port. The low side pressure should not rise. If it does, there could
be a leak through one (or more) of following components: hot gas solenoid, purge valve, or receiver tank pressure check valve.
7. Disconnect the purge valve wires from the main wire harness and use jumper wires to energize the purge valve. The discharge
pressure and the low side pressure should equalize when the purge valve is energized.
8. De-energize the purge valve by disconnecting the jumper wires when the discharge pressure and the low side pressure have
equalized.
9. Watch the gauges attached to the discharge service valve and the receiver tank. The discharge pressure should not rise and
the receiver tank pressure should not fall. If the discharge pressure rises, the condenser check valve is probably leaking.
10. Energize the purge valve with jumper wires and leave it energized.
11. Crack the receiver tank outlet valve open and allow refrigerant into the low side until the low side pressure is above the
discharge pressure, but below the receiver tank pressure. Close the receiver tank outlet valve when the low side pressure is
above the discharge pressure and below the receiver tank pressure.
12. Watch the gauge attached to the discharge service valve. The discharge pressure should not rise. If the discharge pressure
rises, the purge check valve is probably leaking.
13. De-energize the purge valve by disconnecting the jumper wires and reconnect the purge valve wires to the main wire harness.
14. Back seat the receiver tank outlet valve and suction service valve. Perform a “Refrigerant Gauge Removal” procedure.