Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

Page: 187 / 436

[7-5 Error Code Definitions and Solutions: Codes [3000 - 3999] ]
24
- chapter 7 BS_07_E
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7-5-2 Error Code [3511]
1. Error code definition
Refrigerant overcooling
2. Error definition and error detection method
1) If the condition "THHS ≤ A
*1
°C remains true for continuous 6 minutes and 30 seconds" is met (for the first time) during oper-
ation, the outdoor unit will stop, go into the three-minute restart delay mode, and then automatically resume operation after
three minutes have passed.
2) If the condition "THHS ≤ A
*1
°C remains true for continuous 6 minutes and 30 seconds" is met again (for the second time)
within 30 minutes of the first stoppage of the outdoor unit explained above, the outdoor unit will stop, go into the three-minute
restart delay mode, and then automatically resume operation after three minutes have passed.
3) If the condition "THHS ≤ A
*1
°C remains true for continuous 6 minutes and 30 seconds" is met again (for the third time) within
30 minutes of the second stoppage of the outdoor unit explained above and before the condition "THHS > A
*1
°C remains true
for continuous 2 minutes" has been met, the unit will come to an abnormal stop, and this error will be indicated as "3511."
4) If the condition "THHS ≤ A
*1
°C remains true for continuous 6 minutes and 30 seconds" is met (regardless of the first or second
time) after 30 minutes of the first occurrence or after the condition "THHS > A
*1
°C remains true for continuous 2 minutes" has
been met, it is considered as the first occurrence, and the unit will follow the same behavior as the one described in item 1)
above.
5) For 30 minutes after the stoppage of the outdoor unit, or the period up to the time when the condition "THHS > A
*1
°C remains
true for continuous 2 minutes" has been met is considered as a preliminary error, and this state will be indicated on the LED.
*1 During cooling: A = Outside temperature TH7; During heating: A = Evaporation temperature Te
3. Cause, check method and remedy
Cause Check method and remedy
(1) Outdoor unit LEV9 malfunction Check the operation of unit in the Cooing or in the Heating
mode.
LEV9
Refer to [8-8 Troubleshooting LEV, FCV Problems].
(2) THHS failure 1) Check the IGBT on the INV board for proper mounting.
2) Check the THHS sensor reading on the LED.
→ Replace the INV board if the THHS value is abnormal.
(3) Thermistor failure (TH7) Resistance value of the thermistor
(4) Low-pressure sensor fault Refer to [8-5 Pressure Sensor Circuit Configuration and
Troubleshooting Pressure Sensor Problems]
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