Mitsubishi Electric EHPT20Q-VM2EA Service Manual page 42

10-5. Troubleshooting by inferior phenomena
No. Fault symptom
1 Main remote controller 1. There is no power supply to main remote
display is blank.
2. Power is supplied to main remote
2 Please Wait" remains 1. "Please Wait" is displayed for up to 6
displayed on the main
remote controller.
2. Communication failure between the main
3. Communication failure between FTC and
3 The main screen The main remote controller operations do
appears with a press not work for a while after the settings are
changed in the service menu. This is because
disappears in a second. the system takes time to apply the changes.
4 LED2 on FTC is off. When LED1 on FTC is also off. (See 6.
(See 6. WIRING WIRING DIAGRAM.)
DIAGRAM.)
1.
2. There are problems in the method of
3. FTC failure.
GCH15010
Possible cause
controller.
controller, however, the display on the
main remote controller does not appear.
minutes.
remote controller and FTC.
outdoor unit.
connecting the connectors.
1. Check LED2 on FTC. (See 6. WIRING DIAGRAM.)
(i) When LED2 is lit.
Check for damage or contact failure of the main remote controller wiring.
(ii) When LED2 is blinking.
Refer to No. 5 below.
(iii) When LED2 is not lit.
Refer to No. 4 below.
2. Check the following:
Disconnection between the main remote controller cable and the FTC control
board
1. Normal operation
2, 3. Main remote controller start up checks/procedure.
(i)
communication error between the main remote controller and the FTC control
board.
(ii) If is displayed there is a communication error between the outdoor
unit's and FTC's control boards.
Check the wiring connections on the outdoor unit control board and the FTC
control board.
(Ensure S3 is securely wired with no damage. (See 7. FIELD WIRING.)
Normal operation
The cylinder unit is applying updated settings made in the service menu.
Normal operation will start shortly.
AC. 1. Check the voltage across the L and N terminals on the indoor power supply
terminal block 1. (See 7. FIELD WIRING.)
supply.
2. Check for faulty wiring between the connectors.
When the connectors are wired incorrectly
to below. (See 7. FIELD WIRING and a wiring diagram on the control and
electrical box cover.)
Modified settings
(Separate power supply to the cylinder unit)
Cylinder unit
Cylinder unit
control board
XBL XBN
TB1
L N
If there is no problem with the wiring, go to 3. below.
3. Check the FTC control board.
If there is no problem with the wiring, the FTC control board is faulty .
42
Explanation - Solution
Wait" is not displayed.
Wait" is displayed.
Wait" there is a
r.
AC, check for faulty wiring to power
AC, go to 2. below.
them correctly referring
CN3C
TB2
S1 S2 S3
S3
S2
S1