Service Manual

33
OCH636B
<Abnormalities detected while unit is operating>
Check code Abnormal points and detection method Cause judgment and action
U1
(1302)
High pressure (High-pressure switch
63H operated)
Abnormal if High-pressure switch 63H
worked (*) during compressor operation.
*602 PSIG [4.15 MPa]
63H: High-pressure switch
1 Short cycle of indoor unit
2 Clogged filter of indoor unit
3 Decreased airflow caused by
dirt of indoor fan
4 Dirt of indoor heat exchanger
5 Locked indoor fan motor
6 Malfunction of indoor fan motor
7 Defective operation of stop
valve (Not full open)
8 Clogged or broken pipe
9 Locked outdoor fan motor
0
Malfunction of outdoor fan motor
1 Short cycle of outdoor unit
2 Dirt of outdoor heat exchanger
3 Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
4 Disconnection or contact failure
of connector (63H) on outdoor
controller board
5 Disconnection or contact failure
of 63H connection
6 Defective outdoor controller board
7 Defective action of linear
expansion valve
8 Malfunction of fan driving circuit
1–6 Check indoor unit and repair the defect.
7 Check if stop valve is fully open.
8 Check piping and repair the defect.
9–2 Check outdoor unit and repair the defect.
3 Check the inspected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool: Refer
to "10-10. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
4–6 Turn the power off and check F5 is
displayed when the power is on again.
When F5 is displayed, refer to “Judgment
and action” for F5.
7 Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS" and "10-7. HOW TO CHECK THE
COMPONENTS".
8 Replace outdoor controller board.
U2
(TH4: 1102)
(TH33: 1132)
High discharge temperature
High comp. surface temperature
(1) Abnormal if discharge temperature ther-
mistor (TH4) exceeds 257˚F [125°C] or
230˚F [110°C] continuously for 5 minutes.
Abnormal if condenser/evaporator tem-
perature thermistor (TH5) exceeds 104˚F
[40°C] during defrosting and discharge
temperature thermistor (TH4) exceeds
230˚F [110°C].
(2) Abnormal if discharge superheat
(Cooling: TH4 −TH5
Heating: TH4−TH6) increases.
All the conditions in A or B are detected
simultaneously for 10 minutes continu-
ously after 6 minutes past from com-
pressor Startup (including the thermostat
indication or recovery from defrosting).
<Condition A>
• Heating mode
• When discharge superheat is less than
126˚F [70°C].
• When the TH6 temp is more than the
value obtained by TH7−9˚F [5°C].
• When the condensing temp of TH5 is
less than 95˚F [35°C].
<Condition B>
• During comp. operation (Cooling and
Heating)
• When discharge superheat is less than
144˚F [80°C] in cooling.
• When discharge super heat is less
than 162˚F [90°C] in heating.
• When condensing temp of TH6 is more
than −40˚F [−40°C] (In cooling only).
(3) Abnormal if comp. surface temperature
thermistor (TH33) exceeds 239˚F [115°C]
or 221˚F [105°C] continuously for 5
monitues.
A12–30N: 257˚F [125°C] or 230˚F [110°C]
A36, 42N: 239˚F [115°C] or 221˚F [105°C]
1 Overheated compressor opera-
tion caused by shortage of
refrigerant
2 Defective operation of stop
valve
3 Defective thermistor
4 Defective outdoor controller
board
5 Defective action of linear
expansion valve
1 Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
2 Check if stop valve is fully open.
34 Turn the power off and check if U3 is dis-
played when the power is on again.
When U3 is displayed, refer to “Judgment
and action” for U3.
5 Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS" and "10-7. HOW TO CHECK THE
COMPONENTS".