Service manual

35
Check of outdoor thermistors
G
When POWER lamp flashes 6-time.
The thermistors in the outdoor unit are abnormal.
Check of R.V. coil
H
Unit operates COOL mode even if it is set to HEAT mode.
Unit operates HEAT mode even if it is set to COOL mode.
Measure the
resistance
between CN641
1 and 2.
Measure the
resistance
between CN642
1 and 2.
No
Yes
Replace the
thermistor
except RT64.
In case that
RT64 is
abnormal,
replace the
inverter P.C.
board, since
RT64 is
combined with
the inverter P.C.
board.
Replace the inverter
P.C. board.
Disconnect the connectors CN641, CN642 and CN643 from the inverter P.C. board.
(Check the characteristics of each thermistor.)
Defrost thermistor RT61
Measure the
resistance
between CN641
3 and 4.
Reconnect the
connectors
CN641, CN642
and CN643.
Turn ON the
power supply and
press
EMERGENCY
OPERATION
switch.
Discharge
temperature
thermistor RT62
Fin temperature
thermistor RT64
Does the
resistance of the
thermistor have the
characteristics
(11-7.1.)?
No
Yes
Does the unit operate
10 minutes or more?
OK.
(Cause is poor
contact.)
Measure the
resistance
between CN643
1 and 2.
Ambient
temperature
thermistor RT65
Disconnect connector (CN61) between
the compressor and intelligent power
module.
Turn ON the power supply and press
EMERGENCY OPERATION switch
twice (HEAT mode).
Is there 230V AC between CN7211 and
2 on the power P.C.board 3 minutes after
the power supply is turned ON?
Yes
No
Replace the
power P.C. board.
Replace the 4-way valve.
Replace the 4-way valve.
Disconnect connector (CN61) between
the compressor and the intelligent power
module.
Turn ON the power supply and press
EMERGENCY OPERATION switch once
(COOL mode).
Is there 230V AC between CN7211 and
2 on the power P.C. board 3 minutes after
the power supply is turned ON?
No
Yes
Replace the
power P.C. board.
w First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 11-5.
w In case CN721 is not connected or R.V. coil is open, voltage is generated between the
terminal pins of the connector although any signal is not being transmitted to R.V. coil.
Check if CN721 is connected.
CN721
Power P.C. board
(Soldered side)
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