1501 fault mitsubishi vrf

[pingu]

hi what would cause a 1501 fault apart from overcharging of gas ow its on 410a

[Brian_UK]

I thought that a 1501 fault was an undercharge fault which means there is a leak somewhere.

[Thermatech]

1500 is for overcharge
The outdoor unit looks at the discharge pressure & discharge temperature & then calculates the discharge superheat.
If the discharge superheat is less than 10 deg C & the outdoor unit stops at this condition twice in 30 mins then the system stops on 1500 fault.
The system has major liquid flood back to outdoor unit or the sensors are providing incorrect data to the outdoor control circuit board.
If the system has correct refrigerant charge then other possible causes are
1/ discharge pressure sensor incorrect data.
2/ discharge temp sensor incorrect data.
3/ a liquid to suction bypass in the system which is allowing liquid to flood back to the outdoor unit & overflow the suction accumulator.

For 1501 fault please provide outdoor model number

[martinw58]

this is from mitsi manual 1500 fault code can not find 1501 fault code

1500 Refrigerant
overcharge
An error can be detected
by the discharge temperature
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-restart
mode for 20 seconds,
and restarts
after 20 seconds automatically.
2. If the discharge SH
10K or less is detected
again within 30 minutes
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 described
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 thermistor
(TH11, TH12)
Check the temperature and the pressure

of the sensor with LED monitor