Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 195

[ IX Troubleshooting ]
Error Code
1302 Abnormal high
pressure 2
(heat source
unit)
1500 Refrigerant
overcharge
2000 Pump interlock
trouble
Error definition and error
detection method
If the pressure of
(1) Inner pressure drop due to a
0.098MPa [14psi] or low-
(2) Pressure sensor failure
er is registered on the
(3) Shorted-circuited pressure
pressure sensor immedi-
ately before start-up, it
will trigger an abnormal
(4) A pin on the male connector
stop, and error code
"1302" will be displayed.
(5) Disconnected pressure sen-
(6) Failure of the pressure sen-
An error can be detected (1) Overcharged refrigerant
by the discharge temper-
ature superheat.
(2) Thermistor input circuit
1. If the discharge SH
10K [18°F] or less is
(3) Faulty mounting of ther-
detected during oper-
ation (the first detec-
tion), the heat source
unit stops at once,
turns to anti-restart
mode for 3 minutes,
and restarts after 3
minutes automatically.
2. If the discharge SH
10K [18°F] or less is
detected again within
30 minutes after first
stop of the heat
source unit (the sec-
ond detection), the
heat source unit will
make an error stop,
and the error code
"1500" is displayed.
3. If discharge SH 10K
[18°F] or less is de-
tected more than 30
minutes after the heat
source unit stops, and
the operation de-
scribed in step 1
above will start.
4. For 30 minutes after
the stop of the heat
source unit, prelimi-
nary errors will be dis-
played on the LED
display.
The unit comes to an ab- (1) Heat source water pump
normal stop when the
pump interlock circuit re- (2) Broken or disconnected
mains open for ten min-
utes while the unit is not (3) Connector disconnection,
in the stop mode. The
code "2000" will be dis- (4) Failure of the interlock in-
played if Dip SW 2-8 on
the heat source unit con-
trol board is set to OFF. (5) Failure of the interlock in-
Cause
leakage.
sensor cable due to torn out-
er rubber
on the pressure sensor is
missing or contact failure
sor cable
sor input circuit on the con-
troller board
failure on the main board
mistor (TH11)
failure
wires
contact failure
put circuit on the relay
board
put circuit on the control
board
- 186 -
Check method and remedy
Refer to the page on the trouble-
shooting of the high pressure sen-
sor.
Refer to the page on refrigerant
amount evaluation.
Check the temperature and the pres-
sure of the sensor with LED monitor.