Low-Voltage Detection Or Over-Voltage Detection - Daikin Super Multi NX FFQ25B8V1B Service Manual

SiBE121021_C

7.17 Low-voltage Detection or Over-voltage Detection

U2
Remote
Controller
Display
Outdoor Unit LED A
Display
Method of Low-voltage detection:
An abnormal voltage drop is detected by the DC voltage detection circuit.
Malfunction
Detection
Over-voltage detection:
An abnormal voltage rise is detected by the over-voltage detection circuit.
Malfunction Low-voltage detection:
Decision
Conditions
Over-voltage detection:
Supposed
Causes
Troubleshooting
Service Diagnosis
j i h h i
1 2 3 4
The voltage detected by the DC voltage detection circuit is below 150 V for 0.1 second.
If the error repeats 16 times, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer.
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Supply voltage is not as specified.
Defective DC voltage detection circuit
Defective over-voltage detection circuit
Defective PAM control part
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Check the supply voltage.
Supply voltage as
specified?
YES
Rotate the fan by hand.
Does the fan rotate
smoothly?
YES
Turn on the power
again. System
restarted?
NO
Repeat a few
times.
h
5
NO
NO
(Precaution before turning on the power again)
Make sure the power has been off for
at least 30 seconds.
YES
Disturbance factors
∗ Noise ∗ Power supply distortion
Troubleshooting for Outdoor Unit
Correct the power supply.
Replace the fan motor or
the outdoor unit PCB.
Check for such factors for a
long term.
∗ Try to restart a few times.
Replace the outdoor unit
PCB.
(R7150)
359