227
TROUBLESHOOTING
49) Inspect Reversing Valve
If the slide valve is locked at the middle position due to the operation failure of the reversing valve, the hot
gas leaks into the inlet side, increasing the intake temperature and eventually, increases of the discharge
temperature.
NOTE) When replacing the refrigerant system parts, Refer to P221, [Technical Data When Replacing the Re-
frigerant System Parts].
50) Check for Readings of the Compressor Discharge Pipe Temperature Sensor
1. Check for disconnection or short circuit between terminals on the main PCB and relay connector.
1. Turn ON the electric leakage breaker.
2. Check that a hissing noise is not generated from the revers-
ing valve unit during operation.
3. Check if there is a temperature difference of refrigerant vapor
on the low pressure side between the inlet and outlet of the
reversing valve.
4. Check output voltage (200 V AC) is not continuously applied
to the electromagnetic coil, during connection at CN11 [2]-[8]
on the main PCB in cooling.
Resistance value Condition
∞ Disconnection
0 Ω Short circuit
2. Check compressor discharge pipe temperature during
operation with the monitor mode of the board mainte-
nance functions.
3. Measure actual temperature with a thermometer, and
check for the sensor reading's extreme deviation from
the actual temperature.
4. Measure the resistance value of the compressor
discharge pipe temperature sensor on the main PCB,
and check for extreme deviation from the standard
value.
Code No. Temperature Standard resistance value
Compressor discharge pipe temperature 1 No.46 32 ℉ (0 ℃ ) 182.9 kΩ
Compressor discharge pipe temperature 2 No.47 68 ℉ (20 ℃ ) 70.4 kΩ
122 ℉ (50 ℃ ) 20.2 kΩ
Measure point (on main PCB) 176 ℉ (80 ℃ ) 7.0 kΩ
Compressor discharge pipe temperature 1 CN4[27]-[28] 212 ℉ (100 ℃ ) 3.7 kΩ
Compressor discharge pipe temperature 2 CN4[25]-[26] 248 ℉ (120 ℃ ) 2.1 kΩ
Outlet side in heating
Inlet side
Outlet side in cooling
Coil
Compressor discharge pipe tempera
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