Mitsubishi Electric PQHY-P120THMU-A, Service Handbook

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[
IX
Troubleshooting ]
- 238 - HWE09080 GB
1. Error Code
Drain sensor submergence (Models with a drain sensor)
2. Error definition and error detection method
1) If an immersion of the drain sensor in the water is detected while the unit is in any mode other than the Cool/Dry mode and
when the drain pump goes from OFF to ON, this condition is considered preliminary water leakage. While this error is being
detected, humidifier output cannot be turned on.(Applicable to the units manufactured in or after October 1996)
2) If the immersion of the sensor in the water is detected four consecutive times at an hour interval, this is considered water leak-
age, and "2500" appears on the monitor.
3) Detection of water leakage is also performed while the unit is stopped.
4) Preliminary water leakage is cancelled when the following conditions are met:
One hour after the preliminary water leakage was detected, it is not detected that the drain pump goes from OFF to ON.
The operation mode is changed to Cool/Dry.
Liquid pipe temperature - inlet temperature -10°C[ -18°F]
3. Cause, check method and remedy
2500
Cause Check method and remedy
(1) Drain water drainage problem
Œ
Clogged drain pump
Œ
Clogged drain piping
Œ
Backflow of drain water from other units
Check for proper drainage.
(2) Adhesion of water drops to the drain sensor
Œ
Trickling of water along the lead wire
Œ
Rippling of drain water caused by filter clogging
1) Check for proper lead wire installation.
2) Check for clogged filter.
(3) Failure of the relay circuit for the solenoid valve Replace the relay.
(4) Indoor unit control board failure
Œ
Drain sensor circuit failure
If the above item checks out OK, replace the indoor unit
control board.