Troubleshooting According To The Remote Controller Malfunction - Mitsubishi Electric PURY-P72 Service Handbook

[ IX Troubleshooting ]
-1- Troubleshooting according to the remote controller malfunction or the external input error
In the case of MA remote controller
1. Phenomena
Even if the operation button on the remote controller is pressed, the display remains unlit and the unit does not start run-
ning.(Power indicator
(1) Cause
1) The power is not supplied to the indoor unit.
ŒThe main power of the indoor unit is not on.
ŒThe connector on the indoor unit board has come off.
ŒThe fuse on the indoor unit board has melted.
ŒTransformer failure and disconnected wire of the indoor unit.
2) Incorrect wiring for the MA remote controller
ŒDisconnected wire for the MA remote controller or disconnected line to the terminal block.
ŒShort-circuited MA remote controller wiring
ŒIncorrect wiring of the MA remote controller cables
ŒIncorrect connection of the MA remote wiring to the terminal block for transmission line (TB5) on the indoor unit
ŒWiring mixup between the MA remote controller cable and power supply cable
ŒReversed connection of the wire for the MA remote controller and the M-NET transmission line on the indoor unit
3) The number of the MA remote controllers that are connected to an indoor unit exceeds the allowable range (2 units).
4) The length or the diameter of the wire for the MA remote controller are out of specification.
5) Short circuit of the wire for the remote display output of the outdoor unit or reversed polarity connection of the relay.
6) The indoor unit board failure
7) MA remote controller failure
(2) Check method and remedy
1) Measure voltages of the MA remote controller terminal (among 1 to 3).
ŒIf the voltage is between DC 9 and 12V, the remote controller is a failure.
ŒIf no voltage is applied, check the causes 1) and 3) and if the cause is found, correct it.
If no cause is found, refer to 2).
2) Remove the wire for the remote controller from the terminal block (TB15) on the MA remote controller for the indoor unit, and
check voltage among 1 to 3.
ŒIf the voltage is between DC 9 and 12 V, check the causes 2) and 4) and if the cause is found, correct it.
ŒIf no voltage is applied, check the cause 1) and if the cause is found, correct it.
If no cause is found, check the wire for the remote display output (relay polarity).
If no further cause is found, replace the indoor unit board.
HWE09130
does not appear on the screen.)
- 272 - GB