Mitsubishi Electric EHGT17D-YM9ED Service Manual page 51

Code Error
Detailed Input current sensor error/
codes L1-phase open error
• Decrease in input current
through heat pump unit
to 0.1A only if operation
frequency is more than or
equal to 40Hz or compres-
04
sor current is more than or
equal to 6A.
U9
(4220)
Abnormal power
synchronous signal
• No input of power
synchronous signal to power
circuit board
08
• Power synchronous signal
of 44 Hz or less, or 65 Hz or
more is detected on power
circuit board.
Abnormal pressure of 63HS
Abnormal if 63HS detects 0.1 MPa or less.
Detection is inoperative for 3 minutes after
UE
compressor starting and 3 minutes after
(1302)
and during defrosting.
63HS: High pressure sensor
Low pressure
Abnormal if TH33-TH4 exceeds 20°C and
UL
TH33 exceeds 80°C during compressor
(1300)
operation.
Compressor overcurrent interruption
(When compressor locked)
UF
Abnormal if overcurrent of DC bus or com-
(4100)
pressor is detected within 30 seconds after
compressor starts operating.
Current sensor error or input current error
• Abnormal if current sensor detects –1.0A
to 1.0A during compressor operation.
(This error is ignored in case of test run
UH
mode.)
(5300)
• Abnormal if 40A of input current is de-
tected or 37A or more of input current is
detected for 10 seconds continuously.
Low brine flow rate (flow switch operated)
Abnormal if flow switch is operated (under
5.5L/min) during compressor operation.
UA
(2511)
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or com-
pressor is detected after compressor starts
operating for 30 seconds.
UP
(4210)
OCH722A
Cause
1. L1-phase open
2. Disconnection or loose connection between TB1
and noise filter circuit board
3. Disconnection or loose connection of CN5 on
the power circuit board/CNCT on the noise filter
board
4. Defective ACCT (AC current trans) on the noise
filter circuit board
5. Defective input current detection circuit in power
circuit board
6. Defective controller circuit board
1. Distortion of power source voltage, noise
superimposition.
2. Disconnection or loose connection of earth
wiring
3. Disconnection or loose connection of CN2 on
the power circuit board /controller circuit board
4. Defective power synchronous signal circuit in
controller circuit board
5. Defective power synchronous signal circuit in
power circuit board
1. Disconnection or contact failure of connector
(63HS) on the controller circuit board
2. Defective pressure sensor
3. Defective controller circuit board
1. Defective linear expansion valve.
2. Defective controller circuit board
1. Decrease of power supply voltage
2. Looseness, disconnection or converse of com-
pressor wiring connection
3. Defective compressor
4. Defective power board
1. Disconnection of compressor wiring
2. Defective circuit of current sensor on power
circuit board
3. Decrease of power supply voltage
4. Leakage or shortage of refrigerant
1. Valve of brine circuit is closed during operation.
2. Disconnection or loose connection of connector
(63L) on controller circuit board
3. Disconnection or loose connection of 63L
4. Defective controller circuit board
5. Leakage or shortage of brine
1. Decrease of power supply voltage
2. Looseness, disconnection or converse of
compressor wiring connection
3. Defective pump of heat pump unit
4. Defective input circuit of controller circuit board
5. Defective compressor
6. Defective power circuit board
7. DIP switch setting difference of controller circuit
board
51
Action
1. Check the field facility for the power supply.
2. Check the wiring between TB1 and noise filter
circuit board.
3. Check CN5/CNCT wiring.
4. Replace noise filter circuit board.
5. Replace power circuit board.
6. Replace controller circuit board.
1. Check the field facility for the power supply.
2. Check earth wiring.
3. Check CN2 wiring.
4. Replace controller circuit board.
5. Replace power circuit board.
1. Check connection of connector (63HS) on the
controller circuit board.
Check breaking of the lead wire for 63HS.
2. Check pressure by microprocessor.
(Pressure sensor/ 63HS)
3. Replace controller circuit board.
1. Check linear expansion valve.
2. Replace controller circuit board.
1. Check facility of power supply.
2. Correct the wiring (U•V•W phase) to compressor.
3. Check compressor.
4. Replace power circuit board.
1. Correct the wiring (U•V•W phase) to compressor.
2. Replace power circuit board.
3. Check the facility of power supply.
4. Check leakage of refrigerant.
1. Check valve.
2. to 4.
Turn the power off and on again to check if F3 is
displayed on restarting.
If F3 is displayed, follow the F3 processing direction.
5. Correct to proper amount of refrigerant.
1. Check facility of power supply.
2. Correct the wiring (U·V·W phase) to compressor.
Refer to "9-7.TEST POINT DIAGRAM" (Power
circuit board).
3. Check pump.
4. Replace controller circuit board.
Note: Before the replacement of the controller
circuit board, disconnect the wiring to
compressor from the 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.
5. Check compressor. Refer to "9-6. Checking
component parts' function".
6. Replace power circuit board.
7. Check the DIP switch setting of controller circuit
board.