Mitsubishi Electric PQHY-P200YLM-A Service Handbook page 343

[ IX Troubleshooting ]
In the case of MA remote controller
3. Phenomena
"HO" or "PLEASE WAIT" display on the remote controller does not disappear, and no operation is performed even if the button
is pressed. ("HO" or "PLEASE WAIT" display will normally turn off 5 minutes later after the power on.)
(1) Cause
1) The power for the M-NET transmission line is not supplied from the heat source unit.
2) Short-circuited transmission line
3) Incorrect wiring of the M-NET transmission line on the heat source 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).
The male power supply connectors on the multiple heat source units are connected to the female power supply switch con-
nector (CN40).
In the system to which the power supply unit for transmission lines is connected, the male power supply connector is connect-
ed to the female power supply switch connector (CN40) on the heat source unit
4) Disconnected M-NET transmission line on the indoor unit.
5) Disconnected wire between the terminal block for M-NET line (TB5) of the indoor unit and the indoor unit board (CN2M) or
disconnected connector.
6) Incorrect wiring for the MA remote controller
Short-circuited wire for the MA remote controller
Disconnected wire for the MA remote controller (No.2) and disconnected line to the terminal block.
Reversed daisy-chain connection between groups
Incorrect wiring for the MA remote controller to the terminal block for transmission line connection (TB5) on the indoor unit
The M-NET transmission line is connected incorrectly to the terminal block (TB13) for the MA remote controller.
7) The sub/main setting of the MA remote controller is set to sub. Two PAR-31MAA controllers are connected.
8) 2 or more main MA remote controllers are connected.
9) Indoor unit board failure (MA remote controller communication circuit)
10) Remote controller failure
11) Heat source unit failure (Refer to IX [9] Troubleshooting Using the Heat source Unit LED Error Display.)
(2) Check method and remedy
1) When 2) and 3) above apply, check code 7102 will be displayed on the self-diagnosis LED on the heat source unit.
Same symptom for all units in a
system with one heat source
unit?
Check the self-diagnosis LED
Is the error code 7102
displayed?
Error found?
Check (1).
Refer to IX [4] -7- (2) "Troubleshooting transmission power circuit of heat source unit" for how to check item 1 in the flow chart
above.
HWE15060
NO
YES
YES
Check
2 and 3.
NO
YES Replace the ME remote
controller with the MA
remote controller
NO
Check 4.
Correct
the error.
Correct
the error.
- 334 -
Measure voltages of the
terminal block for transmission
line (TB5) on the indoor unit.
NO
17 - 30V?
YES
Check for 5 and 6.
YES
Error found?
NO
Indoor unit board or
MA remote controller failure
GB