Outdoor Units Stop At Irregular Times - Mitsubishi Electric PUHY-P250YNW-A Service Handbook

[8-2 Refrigerant Control Problems ]
8-2-2

Outdoor Units Stop at Irregular Times.

1. Phenomena
Outdoor unit stops at times during operation.
2. Cause, check method and remedy
The first stop is not considered as an error, as the
unit turns to anti-restart mode for 3 minutes as a pre-
liminary error.
Error mode
1. Abnormal high pressure
2. Abnormal discharge air temperature
3. Heatsink thermistor failure
4. Thermistor failure
5. Pressure sensor failure
6. Over-current break
7. Refrigerant overcharge
8. Refrigerant cooling error
Note1: Frost prevention tripping only under cooling mode
may be considered in addition to the above. (Freeze
protection is detected by one or all indoor units.)
Note2: Even the second stop is not considered as an error
when some specified errors occur. (eg. The third
stop is considered as an error when the thermistor
error occurs.)
BS_08_C
Cause Check method and remedy
(1) Check the mode operated in the past by displaying
preliminary error history on LED display with SW4.
(2) Reoperate the unit to find the mode that stops the
unit by displaying preliminary error history on LED
display with SW4.
→ Refer to the reference page for each error mode.
*Display the indoor piping temperature table with
SW4 to check whether the freeze proof operation
runs properly, and check the temperature.
Refer to the following page(s). [10 LED Status Indi-
cators on the Outdoor Unit Circuit Board]
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