Troubleshooting - Mitsubishi Electric PAC-IF071B-E Installation Manual

8. Troubleshooting

<Troubleshooting by inferior phenomena>
No. Fault symptom
1 Main remote controller
display is blank.
2 "Please Wait" remains
displayed on the main
remote controller.
3 The main screen
appears with a press
of the "ON" button, but
disappears in a second.
4 LED2 on FTC (Main) is
off.
(See <Figure 4.5.1>.)
en
43
Possible cause
1. There is no power supply to main remote
controller.
2. Power is supplied to main remote
controller, however, the display on the
main remote controller does not appear.
1. "Please Wait" is displayed for up to 6
minutes.
2. Communication failure between the main
remote controller and FTC (Main).
3. Communication failure between FTC
(Main) and outdoor unit.
The main remote controller operations do
not work for a whilst after the settings are
changed in the service menu. This is because
the system takes time to apply the changes.
When LED1 on FTC (Main) is also off. (See
<Figure 4.5.1>.)
<FTC (Main) powered via outdoor unit.>
1. The outdoor unit is not supplied at the
rated voltage.
2. Defective outdoor controller circuit board
3. FTC (Main) is not supplied with 220 to
240V AC
4. FTC (Main) failure
5. Faulty connector wiring
Explanation - Solution
1. Check LED2 on FTC (Main). (See <Figure 4.5.1>.)
(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 (Main)
control board
• Failure of the main remote controller if "Please Wait" is not displayed.
• Refer to No. 2 below if "Please Wait" is displayed.
1. Normal operation.
2, 3. Main remote controller start up checks/procedure.
(i) If "0%" or "50-99%" is displayed below "Please Wait" there is a
communication error between the main remote controller and the FTC (Main)
control board.
• Check wiring connections on the main remote controller.
• Replace the main remote controller or the FTC (Main) control board.
(ii) If "1-49%" is displayed there is a communication error between the outdoor
unit's and FTC (Main) control boards.
• Check the wiring connections on the outdoor unit control board and the FTC
(Main) control board.
(Ensure S1 and S2 are not cross-wired and S3 is securely wired with no
damage. (See section 4.1.)
• Replace the outdoor unit's and/or the FTC (Main) control boards.
Normal operation.
The indoor unit is applying updated settings made in the service menu. Normal
operation will start shortly.
1. Check the voltage across the terminals L and N or L3 and N on the outdoor
power board. (See section 4.1.)
• When the voltage is not 220 to 240V AC, check wiring of the outdoor unit and
of the breaker.
• When the voltage is at 220 to 240V AC, go to "2." below.
2. Check the voltage across the outdoor unit terminals S1 and S2. (See section
4.1.)
• When the voltage is not 220 to 240V AC, check the fuse on the outdoor
control board and check for faulty wiring.
• When the voltage is 220 to 240V AC, go to "3." below.
3. Check the voltage across the indoor unit terminals S1 and S2. (See section 4.1.)
• When the voltage is not 220 to 240V AC, check FTC (Main)-outdoor unit
wiring for faults.
• When the voltage is 220 to 240V AC, go to "4." below.
4. Check the FTC (Main) control board.
• Check the fuse on FTC (Main) control board.
• Check for faulty wiring.
• If no problem found with the wiring, the FTC (Main) control board is faulty.
5. Check the connector wiring.
• When the connectors are wired incorrectly, re-wire the connectors referring to
below. (See section 4.1.)
L
N
FTC (Main)
powered via
outdoor unit
S1
S2
S3
Black
CN01
FTC