Thermo King KD-II SR, Manual

Page: 117 / 182

Refrigeration Maintenance (Rev. 04/03)
103
2. Set the thermostat well below box temperature, and run
the unit in cooling mode until temperature is stabilized
(at least 5 minutes).
3. Close (front seat) the suction service valve. Pump the
compressor down into a deep vacuum (25 in.). Stop the
unit. If the suction pressure does not rise above 10 psig
(69 kPa) in 2 minutes, perform check procedures on the
three-way valve and the bypass check valve. If the pres-
sure does not rise, go to step 4.
4. Front seat discharge service valve, and equalize the
compressor to slightly positive. Disassemble and
inspect the discharge valve plates.
1. Suction Service Valve
2. Compound Gauge
3. High Pressure Gauge (0 to 500 psig)
4. Discharge Service Valve
Install Gauge Manifold
Compound Gauge Indicating 20 in. Vacuum
WARNING: Any time the discharge valve is front
seated, disconnect the unit battery or power source
to prevent accidental compressor start-up.
LOW SIDE PUMP DOWN
NOTE: Operate the unit in COOL for 2 to 5 minutes
before performing the low side pump down.
1. Install a gauge manifold at the compressor.
2. Operate the unit in COOL, front seat the receiver tank
outlet valve and pump down the low side. Then turn the
On/Off switch OFF.
• Pump down the low side to a 20 to 25 in. Hg
vacuum (-68 to -85 kPa). If the unit pumps down
acceptably and then holds at a 15 in. Hg vacuum
(-51 kPa) for 2 minutes or more, it can be assumed
that the receiver tank outlet valve seal, condenser
inlet check valve seal (or hot gas solenoid) and
compressor discharge valve plates are acceptable.