Mitsubishi Electric CMB-WM108V-AA Service Handbook page 146

[ VIII Troubleshooting ]
2501
1. Error Code
2501
Water pump fault
2. Error definition and error detection method
When clogged water circuit or water leaks from the water circuit is detected, the water pump is stopped for protection.
When the following statuses are detected, the pump will be stopped.
The revolutions of the water pump exceeds the specific range.
Pump discharge port: TH34, TH35 > 53ºC [127ºF]
3. Cause, check method and remedy
(1) Water circuit is clogged.
(2) Water leaks from the water circuit
(3) Air infiltration through the air vent valve
(4) Broken or semi-broken thermistor wire
(5) Thermistor failure
(6) Semi-broken pump wire
If a sudden water leak occurs, replace the water pressure protection valves because they may be the cause.
HWE1708A
Cause Check method and remedy
1) Check for tightened water flow rate control valves or field-
installed valves.
2) Check the pump for proper sound.
If there is air in the circuit, it makes a noise.
3) Check that any air vent valves are not installed in the water
circuit on the suction side water pump.
If an air vent valve is installed in the water circuit on the suc-
tion side water pump, it will cause the air infiltration.
4) Check for a broken thermistor wire.
5) Check the resistance of the thermistor.
0°C [32°F] : 6.0kΩ
10°C [50°F] : 3.9kΩ
20°C [68°F]: 2.6kΩ
30°C [86°F] : 1.8kΩ
40°C [104°F] : 1.3kΩ
6) Check for semi-broken pump wires.
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