Error Code 2502 - Mitsubishi Electric PQHY-P72TYHMU-A Service Handbook

Table of Contents
[ IX Troubleshooting ]
1. Error Code
2502
Drain pump fault (Models with a drain sensor)
2. Error definition and error detection method
1) Make the drain sensor thermistor self-heat. If the temperature rise is small, it is interpreted that the sensor is immersed in
water. This condition is considered to be a preliminary error, and the unit goes into the 3-minute restart delay mode.
2) If another episode of the above condition is detected during the preliminary error, this is considered a drain pump error, and
"2502" appears on the monitor.
3) This error is always detected while the drain pump is in operation.
4) The following criteria are met when the criteria for the forced stoppage of heat source unit (system stoppage) are met.
"Liquid pipe temperature - inlet temperature
The immersion of drain sensor is detected 10 consecutive times.
The conditions that are listed under items 1) through 3) above are always met before the criteria for the forced stoppage
of the heat source unit.
5) The indoor unit that detected the conditions that are listed in item 4) above brings the heat source unit in the same refrigerant
circuit to an error stop (compressor operation prohibited), and the heat source unit brings all the indoor units in the same re-
frigerant circuit that are in any mode other than Fan or Stop to an error stop. "2502" appears on the monitor of the units that
came to an error stop.
6) Forced stoppage of the heat source unit
Detection timing: The error is detected whether the unit is in operation or stopped.
7) Ending criteria for the forced stoppage of heat source unit
Power reset the indoor unit that was identified as the error source and the heat source unit that is connected to the same
refrigerant circuit.
Forced stoppage of the heat source 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
ŒClogged drain pump
ŒClogged drain piping
(3)
Adhesion of water drops to the drain sensor
ŒTrickling of water along the lead wire
ŒRippling of drain water caused by filter clogging
(4)
Indoor unit control board failure
ŒDrain pump drive circuit failure
ŒDrain heater output circuit failure
(5)
Items (1) through (4) above and an indoor unit elec-
tronic valve closure failure (leaky valve) occurred si-
multaneously.
HWE09080
- 10 °C [ -18°F] " has been detected for 30 minutes.
Cause
- 240 -
Check method and remedy
Check for proper functioning of the drain pump.
Check for proper drainage.
1)
Check for proper lead wire installation.
2)
Check for clogged filter.
If the above item checks out OK, replace the indoor unit
control board.
Check the solenoid valves on the indoor unit for leaks.
GB

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