Emergency Operation - Mitsubishi Electric PEY Series Service Manual

TROUBLESHOOTING

9-5. Emergency operation

9-5-1. When wireless remote controller fails or its battery is exhausted
ON/OFF
COOL
9-5-2. When wired remote controller or indoor unit microprocessor fails
(1) When the wired remote control or the indoor unit microprocessor has failed, but all other components work properly, if you
set the switch (SWE) on the indoor controller board ON, the indoor unit will begin emergency operation.
When emergency operation is activated, the indoor unit operates as follows:
1) Indoor fan is running at high speed.
2) Drain pump is operating.
* Note on the wireless remote control: when the remote control does not function, it is possible to activate emergency
operation by using the indoor unit emergency operation switch (SW1, SW2 of the wireless signal receiver board).
However, if the indoor unit microprocessor has failed, it is necessary to proceed with points 2) and 3) below as in the
case of the wired remote controller.
(2) When you activate emergency operation of the cooling or heating, you have to set the switch (SWE) on the indoor controller
board and activate emergency operation of the outdoor unit.
For details on how to activate emergency operation of the outdoor unit, refer to the outdoor unit wiring diagram.
(3) Before you activate emergency operation, check the following points:
1) Emergency operation cannot be activated when:
• The outdoor unit malfunctions.
• The indoor fan malfunctions.
• When it has detected the malfunction of drain pump during self-diagnosing.
2) Emergency operation becomes continuous only by switching the power source on/off.
ON/OFF on the remote control or temperature control etc. does not function.
3) Avoid operating for a long time when the outdoor unit begins defrosting while emergency operation of the heating is
activated because it will start to blow cold air.
4) Emergency cooling should be limited to 10 hours maximum (The indoor unit heat exchanger may freeze).
5) After emergency operation has been deactivated, set the switches etc. to their original positions.
6) Movement of the vanes does not work in emergency operation, therefore you have to slowly set them manually to the
appropriate position.
HWE1305A
1 ON/OFF lamp (lit when unit is operating; unlit when unit is not operating)
2 Emergency operation
In cases where the remote control unit does not operate properly, use the
1
COOL button on the wireless remote control signal receiver to toggle the
unit on or off.
Operation mode
2
Preset temperature
Fan speed
COOL
24°C/75°F
High
37