Mitsubishi Electric PUZ-ZM200YKA2-ET Service Manual page 46

Check Code Abnormal points and detection method
Low pressure
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts heating operating for 10
minutes.
TH7−TH3 4°C and
TH5-Indoor room temperature
Thermistor TH3: Outdoor liquid pipe temperature
TH5: Indoor cond./eva. temperature
UL
TH7: Ambient temperature
(1300)
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or compres-
sor is detected after compressor starts oper-
ating for 30 seconds.
UP
(4210)
Remote controller transmission error (E0)/
signal receiving error (E4)
Abnormal if main or sub remote controller
cannot receive normally any transmission
from indoor unit of refrigerant address "0" for
3 minutes. (Check code: E0)
Abnormal if sub remote controller could not
receive any signal for 2 minutes. (Check
code: E0)
Abnormal if indoor controller board can not
receive normally any data from remote con-
troller board or from other indoor controller
E0
board for 3 minutes. (Check code: E4)
or
E4
Indoor controller board cannot receive any
signal from remote controller for 2 minutes.
(Check code: E4)
OCH771C
Cause
Stop valve of outdoor unit is
closed during operation.
Leakage or shortage of refrigerant
Malfunction of linear expansion
2°C valve
Clogging with foreign objects in
refrigerant circuit
Note: If water enters in refrigerant
circuit, clogging may occur
where the part becomes
below freezing point.
Stop valve of outdoor unit is
closed.
Decrease of power supply voltage
Looseness, disconnection or
reverse of compressor wiring con-
nection
Defective fan of indoor/outdoor
units
Short cycle of indoor/outdoor
units
Defective input circuit of outdoor
controller board
Defective compressor
Defective outdoor power circuit
board
DIP switch setting difference of
outdoor controller circuit board
Contact failure at transmission
wire of remote controller
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 out-
door controller circuit board.
Miswiring of remote controller
Defective transmitting receiving
circuit of remote controller
Defective transmitting receiving
circuit of indoor controller board
of refrigerant address "0"
Noise has entered into the trans-
mission wire of remote controller.
46
Judgment and action
Check stop valve.
Check intake superheat.
Check leakage of refrigerant.
Check additional refrigerant.
Check linear expansion valve.
Refer to "10-5. HOW TO CHECK THE
PARTS".
After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
Open stop valve.
Check facility of power supply.
Correct the wiring (U V W phase) to com-
• •
pressor. Refer to "10-8. TEST POINT
DIAGRAM". (Outdoor power circuit board).
Check indoor/outdoor fan.
Solve short cycle.
Replace outdoor controller circuit board.
Check compressor. Refer to "10-5. HOW
TO CHECK THE PARTS".
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.
Replace outdoor power circuit board
Check the DIP switch setting of outdoor
controller circuit board
Check disconnection or looseness of indoor
unit or transmission wire of remote controller.
Set one of the remote controllers "main" if
there is no problem with the action above.
Check wiring of remote controller.
• Total wiring length: maximum 500 m
(Do not use cable 3 or more.)
• The number of connecting indoor units:
maximum 16 units
• The number of connecting remote con-
troller: maximum 2 units
If the cause of trouble is not any of – above,
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 occurs 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: If the unit is not normal after replacing indoor
controller board in group control, indoor con-
troller board of address "0" may be abnormal.