wsm STW37 Workshop Manual page 515

STW34, STW37, STW40, WSM
Refrigerant Fails to Circulate
1. Symptoms seen in refrigerating cycle
• LO pressure side (1) pressure is vacuum and, HI pressure
side (2) is low pressure.
LO pressure side (1)
Vacuum
HI pressure side (2)
0.49 to 0.59 MPa (5 to 6 kgf/cm
2. Probable cause
• Refrigerant flow obstructed by moisture or dirt in the
refrigerating cycle freezing or sticking on the expansion
valve orifice.
3. Solution
Allow to stand for same time and then resume operation to
decide whether the plugging is due to moisture or dirt.
• If caused by moisture, correct by referring to instructions in
previous.
• If caused by dirt, remove the expansion valve and blow out
the dirt with compressed air.
• If unable to remove the dirt, replace the expansion valve.
Replace the receiver. Evacuate and charge in proper
amount of new refrigerant. (See page 10-S20.)
• If caused by gas leakage in heat sensitizing tube, replace
the expansion valve.
(1) LO Pressure Side
Expansion Valve Opens Too Far or Improper Installation of
Heat Sensitizing Tube
1. Symptoms seen in refrigerating cycle
• Both LO and HI pressure side (1), (2) pressures too high.
LO pressure side (1)
0.29 to 0.39 MPa (3 to 4 kgf/cm
HI pressure side (2)
1.96 to 2.45 MPa (20 to 25 kgf/cm
• Frost or heavy dew on low pressure side piping.
2. Probable cause
• Expansion valve trouble or heat sensitizing tube improperly
installed.
• Flow adjustment not properly done.
3. Solution
• Check installed condition of heat sensitizing tube.
• If installation of heat sensitizing tube is correct, replace the
expansion valve.
(1) LO Pressure Side
10-S16
2
, 71.2 to 85.3 psi)
(2) HI Pressure Side
9Y1211109CAS0023US0
2
, 42.7 to 56.9 psi)
2
, 284.5 to 355.6 psi)
(2) HI Pressure Side
9Y1211109CAS0024US0
KiSC issued 11, 2014 A
CABIN