Mitsubishi Electric PU(H)Y-P250YGM-A, Service Handbook

Page: 127 / 215

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[
IX
Troubleshooting ]
1500 Refrigerant
overcharge An error can be detected
by the discharge temper-
ature superheat.
1. If the discharge SH
10K or less is detected
during operation (the
first detection), the
outdoor unit stops at
once, turns to anti-re-
start mode for 20 sec-
onds, and restarts
after 20 seconds auto-
matically.
2. If the discharge SH
10K or less is detected
again within 30 min-
utes after first stop of
the outdoor unit (the
second detection), the
outdoor unit will make
an error stop, and the
error code "1500" is
displayed.
3. If discharge SH 10K or
less is detected more
than 30 minutes after
the outdoor unit stops,
and the operation de-
scribed in step 1
above will start.
4. For 30 minutes after
the stop of the outdoor
unit, preliminary errors
will be displayed on
the LED display.
(1) Overcharged refrigerant Refer to the page on refrigerant
amount evaluation.
(2) Thermistor input circuit
failure on the main board
(3) Faulty mounting of ther-
mistor (TH11, TH12)
Check the temperature and the pres-
sure of the sensor with LED monitor.
2503 Float switch
trip When the float switch
trips during operation,
and when an open is de-
tected (cannot be detect-
ed during OFF).
Open :
detectable at
-40°C or lower (1) Drainage failure
(2) Connector contact failure
(loose connector)
(3) Disconnection or partial
disconnection of the float
switch wiring
Check the drain pan, drain hose, and
drainage.
Check that the resistance of the float
switch is 250 milliohm or less.
Indoor board (detection circuit)
failure Check the connector contact.
If no fault is found, the indoor board
is a failure.
Error Code
Error definition and error
detection method
Cause Check method and remedy