22
10-6. TROUBLESHOOTING FLOW
A Check of indoor fan motor
The indoor fan motor error has occurred, and the indoor fan does not operate.
Turn OFF the power supply.
Is there any foreign matter that interferes
the rotation of the line
fl
ow fan?
Yes
No
Remove the foreign matter and
adjust the line
fl
ow fan.
Pay enough attention to the high voltage on the fan motor connector CN211.
Turn ON the power supply, wait 5 seconds or more, and then press
EMERGENCY OPERATION switch.
Measure the supply voltage as follows within 12 seconds after EMER-
GENCY OPERATION switch is pressed.
If more than 12 seconds passes, turn OFF the power supply and turn it
ON again, then measure the voltage.
<Indoor power P.C. board>
1. Measure the voltage between CN211 (+) and (–).
2. Measure the voltage between CN211 (+) and (–).
<Indoor electronic control P.C. board>
3. Measure the voltage between CN10A (+) and GND (–).
If more than 12 seconds passes after EMERGENCY OPERATION switch
is pressed, the voltage measured at 2. above goes 0 VDC although the
indoor P.C. board is normal.
Does the voltage between CN211
(+) and (–) on the power P.C. board
rise to the range of 3 to 6 VDC within
12 seconds after EMERGENCY
OPERATION switch is pressed?
Replace the indoor fan motor.
Yes
No
The indoor fan motor error has occurred, and the indoor fan repeats "12-second ON and 30-second OFF" 3 times, and then stops.
Measure the voltage between CN211
(+) and (–) while the fan motor is
rotating.
Replace the indoor power
P.C. board.
Is it unchanged holding
0 or 15 VDC?
No
(Changed)
Yes
(Unchanged)
Measure the voltage CN10A
(+) and GND (–) on the indoor
electronic control P.C board when
the fan motor is rotaring.
Replace the indoor fan motor.
Is there 325 VDC
between CN211 (+)
and (–) ?
Yes
Does the voltage between CN10A
(+) and GND (–) on the indoor
electronic control P.C. board fall to
2 V or less within 12 seconds after
EMERGENCY OPERATION switch is
pressed?
Replace the indoor electronic
control P.C. board.
No
Yes
Replace the indoor power P.C.
board.
Is it unchanged holding
0 or 5 VDC?
No
(Changed)
Yes
(Unchanged)
Replace the indoor
electronic control P.C.
board.
No
OBH750
