Mitsubishi Electric Mr. Slim PUHZ-ZRP35VKA Service Manual page 48

Abnormal points and detection method
Check Code
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°C and
TH5−Indoor room temperature [ 2°C
Detection mode 2
TH7−TH3 [ 2°C and
UL
TH5−Indoor room temperature [ 4°C and
(1300)
TH2−Indoor room temperature [ 4°C
Detection mode 3
TH7−TH3 [ 4°C and
TH5−Indoor room temperature [ 2°C
and TH4−TH5 ] 20°C
2. Cooling mode
TH6−TH7 [ 2°C and
TH3−TH7 [ 2°C and
Indoor room temperature - Indoor liquid
pipe temperature (TH2) [ 5°C
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.
(Check code: E0)
2 Abnormal if sub remote controller could
not receive any signal for 2 minutes.
(Check code: E0)
E0 1 Abnormal if indoor controller board can
not receive normally any data from
or
remote controller board or from other
E4
indoor controller board for 3 minutes.
(Check code: E4)
2 Indoor controller board cannot receive
any signal from remote controller for 2
minutes. (Check code: E4)
OCH527C
Case
1 Stop valve of outdoor unit is
closed during operation.
2 Leakage or shortage of
refrigerant
3 Malfunction of linear expansion
valve
4 Clogging with foreign objects in
refrigerant circuit
Note:
C logging occurs in the parts which
become below freezing point
when water enters in refrigerant
circuit.
1 Stop valve of outdoor unit is closed.
2 Decrease of power supply voltage
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
outdoor 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.
48
Judgment and action
1 Check stop valve.
2 Check intake superheat.
Check leakage of refrigerant.
Check additional refrigerant.
3 Check linear expansion valve.
Refer to "11-6. HOW TO CHECK THE
PARTS".
4 After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
1 O pen stop valve.
2 Check facility of power supply.
3 C orrect the wiring (U V W phase) to compres-
• •
sor. Refer to "11-9. TEST POINT DIAGRAM".
(Outdoor power circuit board).
4 Check indoor/outdoor fan.
5 S olve short cycle.
6 R eplace outdoor controller circuit board.
7 C heck compressor. Refer to "11-6. HOW TO
CHECK THE PARTS".
Note: B efore 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 R eplace outdoor power circuit board
9 C heck 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 controllers
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.
Note: I f the unit is not normal after replacing indoor
controller board in group control, indoor control-
ler board of address "0" may be abnormal.