Mitsubishi Electric Mr. Slim PUHZ-RP71VHA4 Service Manual page 47

Abnormal points and detection method
Error Code
Current sensor error
Abnormal if current sensor detects –1.0A
UH
to 1.0A during compressor operation. (This
(5300)
error is ignored in case of test run mode.)
Low pressure
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts heating operating for 10
minutes.
1. Heating mode
Detection mode 1
TH7-TH3[4: and
TH5-Indoor room temperature[2:
Detection mode 2
TH7-TH3[2:and
TH5-Indoor room temperature[4: and
UL
TH2-Indoor room temperature[4:
(1300)
Detection mode 3
TH7-TH3[4: and
TH5-Indoor room temperature[2:
and TH4-TH5]20:
2. Cooling mode
TH6-TH7[2: and
TH3-TH7[2: and
Indoor room temperature - Indoor liquid
pipe temperature (TH2)[5:
Thermistor TH3: Outdoor liquid pipe temperature
TH4: Discharge temperature
TH5: Indoor cond./eva. temperature
TH6: Outdoor 2-phase pipe temperature
TH7: Outdoor temperature
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or com-
pressor is detected after compressor starts
operating for 30 seconds.
UP
(4210)
Remote controller transmission error
(E0)/signal receiving error (E4)
1 Abnormal if main or sub remote control-
ler cannot receive normally any trans-
mission from indoor unit of refrigerant
address "0" for 3 minutes.
(Error code : E0)
2 Abnormal if sub remote controller could
not receive any signal for 2 minutes.
(Error code: E0)
1 Abnormal if indoor controller board can
E0
not receive normally any data from
or remote controller board or from other
indoor controller board for 3 minutes.
E4
(Error code: E4)
2 Indoor controller board cannot receive
any signal from remote controller for 2
minutes. (Error code: E4)
Case
1 Disconnection of compressor
wiring
2 Defective circuit of current sensor
on outdoor power circuit board
1 Stop valve of outdoor unit is
closed during operation.
2 Leakage or shortage of refriger-
ant
3 Malfunction of linear expansion
valve
4 Clogging with foreign objects in
refrigerant circuit
Clogging occurs in the parts
which become below freez-
ing point when water enters in
refrigerant circuit.
1 Stop valve of outdoor unit is
closed.
2 Decrease of power supply volt-
age
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective fan of indoor/outdoor
units
5 Short cycle of indoor/outdoor
units
6 Defective input circuit of out-
door controller board
7 Defective compressor
8 Defective outdoor power circuit
board
9 Dip switch setting difference of
outdoor controller circuit board
1 Contact failure at transmission
wire of remote controller
2 All remote controllers are set
as "sub" remote controller.
In this case, E0 is displayed
on remote controller, and E4
is displayed at LED (LED1,
LED2) on the outdoor controller
circuit board.
3 Miswiring of remote controller
4 Defective transmitting receiving
circuit of remote controller
5 Defective transmitting receiv-
ing circuit of indoor controller
board of refrigerant address "0"
6 Noise has entered into the
transmission wire of remote
controller.
47
Judgment and action
1 Correct the wiring (U
V W phase) to compres-
• •
sor. Refer to 11-9 (Outdoor power circuit
board).
2 Replace outdoor power circuit board.
1 Check stop valve.
2 Check intake superheat.
Check leakage of refrigerant.
Check additional refrigerant.
3 Check linear expansion valve.
Refer to 11-6.
4 After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U
V W phase) to com-
• •
pressor. Refer to 11-9 (Outdoor power circuit
board).
4 Check indoor/outdoor fan.
5 Solve short cycle.
6 Replace outdoor controller circuit board.
7 Check compressor. Refer to 11-6.
W Before the replacement of the outdoor controller
circuit board, disconnect the wiring to compressor
from the outdoor power circuit board and check the
output voltage among phases, U, V, W, during test
run. No defect on board if voltage among phases
(U-V, V-W and W-U) is same. Make sure to perform
the voltage check with same performing frequency.
8 Replace outdoor power circuit board
9 Check the dip switch setting of outdoor con-
troller circuit board
1 Check disconnection or looseness of indoor
unit or transmission wire of remote controller.
2 Set one of the remote controllers "main" if
there is no problem with the action above.
3 Check wiring of remote controller.
• Total wiring length: max. 500m
(Do not use cable o 3 or more.)
• The number of connecting indoor units:
max. 16 units
• The number of connecting remote control-
ler: max. 2 units
When it is not the above-mentioned problem of
1~3
4 Diagnose remote controllers.
a) When "RC OK" is displayed, remote con-
trollers have no problem. Turn the power
off, and on again to check. If abnormality
generates again, replace indoor controller
board.
b) When "RC NG" is displayed, replace
remote controller.
c) When "RC E3" or "ERC 00-66" is dis-
played, noise may be causing abnormality.
* If the unit is not normal after replacing indoor con-
troller board in group control, indoor controller
board of address "0" may be abnormal.