Drain Pump Fault (Models With A Float Switch) - Mitsubishi Electric CMB-WP1016V-GA1 Service Handbook

[ VIII Troubleshooting ]
1. Error Code
2502

Drain pump fault (Models with a float switch)

2. Error definition and error detection method
1) The immersion of sensor tip in water is detected by the ON/OFF signal from the float switch.
Submergence of the sensor
When it is detected that the float switch has been ON for 15 seconds, it is interpreted that the sensor tip is immersed in
water.
Sensor in the air
When it is detected that the float switch has been OFF for 15 seconds, it is interpreted that the sensor tip is not immersed
in water.
2) If it is detected that the float switch has been ON for 3 minutes after the immersion of the sensor tip was detected, this is con-
sidered a drain pump failure, and "2502" appears on the monitor.
The total time it takes for this error to be detected is 3 minutes and 15 seconds, including the time it takes for the first im-
mersion of the sensor tip to be detected.
3) Detection of drain pump failure is performed while the unit is stopped.
4) The following criteria are met when the criteria for the forced stoppage of outdoor unit (system stoppage) are met.
"Liquid pipe temperature - inlet temperature
It is detected by the float switch that the sensor tip has been immersed in water for 15 minutes or more.
The conditions that are listed under items 1) through 3) above are always met before the criteria for the forced stoppage
of the outdoor unit.
5) The indoor unit and HBC controller that detected the conditions that are listed in item 4) above brings the outdoor unit in the
same refrigerant system to an abnormal stop (compressor operation prohibited), and the outdoor unit brings all the indoor
units and HBC controller in the same refrigerant system that are in any mode other than Fan or Stop to an abnormal stop.
"2502" appears on the monitor of the units that came to an abnormal stop.
6) Forced stoppage of the outdoor unit
Detection timing: The error is detected whether the unit is in operation or stopped.
This error is detected whether the unit is in operation or stopped.
7) Ending criteria for the forced stoppage of outdoor unit
Power reset the indoor unit that was identified as the error source and the outdoor unit that is connected to the same refrig-
erant circuit.
Forced stoppage of the outdoor unit cannot be cancelled by stopping the unit via the remote controller.
(Note) Items 1) - 3) and 4) - 7) are detected independently from each other.
The address and attribute that appear on the remote controller are those of the indoor unit (or OA processing unit)
that caused the error.
3. Cause, check method and remedy
(1) Drain pump failure
(2) Drain water drainage problem
Clogged drain pump
Clogged drain piping
(3) Stuck float switch
Check for slime in the moving parts of the float switch.
(4) Float switch failure
(5) Indoor unit/HBC controller control board fault
Drain pump drive circuit failure
Float switch input circuit failure
(6) Items (1) through (5) above and an indoor unit electronic
valve closure failure (leaky valve) occurred simultane-
ously.
(7) Untightened manual air vent valve
If a sudden water leak occurs, replace the water pressure protection valves because they may be the cause.
During water supply or air vent operation, set the Dip SW 5-2 from OFF to ON. (This error is ignored for nine hours.)
HWE1410A
- 10°C [ -18°F] " has been detected for 30 minutes.
Cause
- 119 -
Check method and remedy
Check for proper functioning of the drain pump
mechanism
Check for proper drainage.
Check for normal operation of the float switch.
Check the resistance with the float switch turned
on and turned off.
Replace indoor unit control board.
Check the solenoid valves on the indoor unit for
leaks.
Visual/Manual inspection
GB