Mitsubishi Electric PUHY-HP144TSHMU-A Service Handbook page 185

[ IX Troubleshooting ]
In case of M-NET 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 running.
(Power indicator does not appear on the screen.)
(1) Cause
1) The power for the M-NET transmission line is not supplied from the outdoor unit.
2) Short circuit of the transmission line.
3) Incorrect wiring of the M-NET transmission line on the outdoor unit.
Disconnected wire for the MA remote controller or disconnected line to the terminal block.
The indoor transmission line is connected incorrectly to the transmission terminal block for centralized controller (TB7).
4) Disconnected transmission line on the remote controller.
5) Remote controller failure
6) Outdoor unit failure (Refer to 9 [7] Troubleshooting Using the Outdoor Unit LED Error Display.)(page 210)
(2) Check method and remedy
1) Check voltage of the transmission terminal block for of the M-NET remote controller.
If voltage between is 17V and 30V -> M-NET remote controller failure
When voltage is 17V or less -> Refer to [4] - 7 - (2) "Outdoor unit transmission power source circuit" .(page 205)
2) When 2) and 3) above apply, check code 7102 will be displayed on the self-diagnosis LED.
HWE0716A
- 176 -
GB