Troubleshooting; Diagnosing Problems For Which No Error Codes Are Available - Mitsubishi Electric QAHV Série Manuel D'installation & D'instructions

6. Troubleshooting

Troubleshooting must be performed only by personnel certified by Mitsubishi Electric.

[1] Diagnosing Problems for which No Error Codes Are Available

If a problem occurs, please check the following. If a protection device has tripped and brought the unit to stop, resolve
the cause of the error before resuming operation.
Resuming operation without removing the causes of an error may damage the unit and its components.
Problem
The unit does not The fuse in the control box
operate. is not blown.
The fuse in the control box
is blown.
Automatic Start/Stop
thermistor has tripped.
Check item
The power lamp on the
The main power is not turned on.
circuit board is not lit.
Measure the circuit
resistance and the earth Short-circuited circuit or ground fault
resistance.
Water temperature is high.
The setting for the automatic Start/Stop
Water temperature is low.
thermistor is too low.
Cause
Switch on the power.
Resolve the cause, and replace the fuse.
Normal
Change the setting for the automatic Start/Stop
thermistor.
GB-61
Solution