Mitsubishi Electric PQHY-P72ZLMU-A Service Handbook page 254

[ IX Troubleshooting ]
1. Error Code
1102
Discharge temperature fault
2. Error definition and error detection method
1) If the discharge temperature of 120 °C [248°F] or more is detected during the above operation (the first detection), the heat
source unit stops once, turns to anti-restart mode for 3 minutes, and restarts after 3 minutes automatically.
2) If the discharge temperature of 120° C [248°F] or more is detected again (the second detection) within 30 minutes after the
second stop of the heat source unit described above, the mode will be changed to 3 - minute restart mode, then the heat
source unit will restart in 3 minutes.
3) If the discharge temperature of 120°C [248°F] or more is detected (the third detection) within 30 minutes after the stop of the
heat source unit described above (regardless of the first or the second stop), the heat source unit will make an error stop, and
the error code "1102" will be displayed.
4) If the discharge temperature of 120°C [248°F] or more is detected more than 30 minutes after the previous stop of the heat
source unit, the detection is regarded as the first detection, and the operation described in step 1 above will start.
5) For 30 minutes after the stop (the first stop or the second stop) of the heat source unit, preliminary errors will be displayed on
the LED display.
3. Cause, check method and remedy
Cause
(1) Gas leak, gas shortage
(2) Overload operation
(3) LEV failure on the indoor unit
(4) BC controller LEV malfunction
Cooling only : LEV3
Cooling main : LEV1,2,3
Heating only or heating
main : LEV3
(5) BC controller SVM1 and 2 malfunction
Cooling only
(6) BC controller SVA malfunction
Cooling only or cooling main
(7) BC controller SVB malfunction
Heating only or heating main
(8) Solenoid valve SV malfunction 4a-4d,7a,7b
:heating only, heating main
(9) Heat source unit LEV1,LEV6,LEV7 actuation
failure
(10) Port address setting error.
(11) Closed ball valve
(12) Insufficient heat source water flow, heat
source water supply cutoff, dirty or clogged
water heat exchanger Heating
(13) Gas leak between low and high pressures
(4-way valve failure, Compressor failure, So-
lenoid valve (SV1a) failure)
(14) Thermistor failure
(TH4)
(15) Input circuit failure on the controller board
thermistor
HWE15150
Check method and remedy
Refer to the page on refrigerant amount evaluation.
Check operating conditions and operation status of indoor/
heat source units.
Perform a heating operation and check the operation.
Cooling: LEV on the indoor unit
BC controller LEV1,2,3
Heat source unit LEV1,LEV7
BC controller SVM1,2
BC controller SVA,C
Heating: LEV on the indoor unit
Heat source unit LEV6,LEV7,SV4a-4d,7a,7b
BC controller LEV3
BC controller SVB
BC controller SV4a - 4d
Refer to the page on troubleshooting LEV.
Confirm the port address of the indoor unit.
Confirm that the ball valve is fully open.
Check the water heat exchanger for clogging.
Check the heat source water circulation pump.
Perform a cooling or heating operation and check the opera-
tion.
Check the thermistor resistor.
Check the inlet air temperature on the LED monitor.
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GB