Thermo King T-1000R, Maintenance Manual

Page: 227 / 282

Refrigeration Maintenance 10-43
HOT GAS SOLENOID (HGS) TEST
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. A low loss fitting must be used on the hose
connected to the suction access port.
2. Operate the unit in low speed cool.
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. Check the temperatures of the refrigeration lines on each side of the HGS by hand. A temperature difference between the two
sides of the HGS indicates it is leaking.
8. 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.
9. From the Interface Board Test Mode select Hot Gas Solenoid.
10. Momentarily (for approximately 1 second) energize the HGS with the Interface Board Test Mode. The low side pressure
should rise slightly. If the low side pressure does not rise, the HGS is not opening. Check the continuity of the wiring and the
solenoid coil before assuming the solenoid is faulty.
11. Back seat the receiver tank outlet valve and the suction service valve. Perform a “Refrigerant Gauge Removal” procedure.
Note: For T-500R/T-Dairy, instead of points 8 thru’ 11 above, please use the following:
Use “Remote Watch” - Relay Test - Hot Gas Solenoid Test (or jumper wires) to momentarily (for approximately 1 second)
energize the HGS. Refer to the appropriate Microprocessor Diagnostic Manual for specific information about “Remote
Watch”. The low side pressure should rise slightly. If the low side pressure does not rise, the HGS is not opening. Check the
continuity of the wiring and the solenoid coil before assuming the solenoid is faulty.
IN-LINE CHECK VALVE REPLACEMENT
This unit uses some in-line check valves. An in-line check valve is not repairable and must be replaced if it fails. A heat sink
must be used on the in-line check valve when it is being soldered in place to prevent damage to the neoprene seal.
Removal
1. Recover the refrigerant charge.
2. Place a heat sink on the check valve.
3. Unsolder the refrigeration lines and remove the check valve.
1. Valve 3. Valve Seat
2. Neoprene Seal 4. Spring
Cross Section of In-line Check Valve
AEA648