Heating - Mitsubishi Electric MXZ-4C36NAHZ Service Manual

Check code
2500
Abnormal points and detection methods
Abnormal if drain sensor or float switch detects to be in the water during
cooling or dry operation.
To release this abnormality, reset the power (turn OFF and ON).
TH21: Indoor intake temperature thermistor (RT11 or TH1)
TH22: Indoor liquid pipe temperature thermistor (RT13 or TH2)
TH23: Branch box gas pipe temperature thermistor (TH-A to E)
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Are there 2 or more
indoor units with different
refrigerant connected?
No
Start heating operation.
Check the temperature
of TH22/23 if they are
within appropriate range.
Are they within the range?
Yes
Turn ON the emergency
operation switch (SWE).
Does the drain pump work?
Yes
Is the drain level
unusually high?
No
Continue to the next page
OCH573
Diagnosis
Yes
Are the refrigerant piping
and the indoor/ outdoor connector
connected in the same unit?
Yes
No
· In heating operation
The temperature difference between
the intake and blowing air:
Approx. 57 to 86°F [14 to 30:]
Piping temperature:
Approx. 104 to 131°F [40 to 55 ]
Note:
The temperature may differ depending
on the operating condition.
No
Yes
Water leakage
Causes and check points
Reverse connection of extended piping (when
connecting multiple units)
Reverse connection of indoor/ outdoor connector
Defective thermistor of TH21 or TH22/23
Defective drain sensor or float switch
Defective drain pump
Poor drainage
· Clogged drain pump
· Clogged drain pipe
Solve the reverse connection, or
No
connect the connectors properly.
Refer to the diagnosis of check code<1100>.
Refer to the diagnosis of check code<2502>.
Check the drain discharge system for:
· Clean the drain pan.
· Clogged drain pump
· Clogged or reverse connection of drain pipe
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Chart 1 of 2
Remedy