Mitsubishi Electric PUZ-ZM60VHA2 Service Manual page 41

<Abnormalities detected while unit is operating>
Check Code Abnormal points and detection method
High pressure (High pressure switch 63H
operated)
Abnormal if high pressure switch 63H
(4.15MPa) operated during compressor
operation.
(ZM60-250)
High compressor temperature
(Thermal protector TRS operated)
TRS(130°C) operated during compressor
operation
(ZM200-250)
U1
(1302)
High discharge temperature
High comp. surface temperature
Abnormal if discharge temperature
thermistor (TH4, TH33) exceeds 120°C
or 110°C (ZM60-140), 117°C or 110°C
(ZM200/250) continuously for 5 minutes.
Abnormal if condenser/evaporator
temperature thermistor (TH5) exceeds 40°C
during defrosting and discharge temperature
thermistor (TH4, TH33) exceeds 110°C.
Abnormal if discharge superheat
(Cooling: TH4 (or TH33)−TH5
Heating: TH4 (or TH33)−TH6) increases.
All the conditions in A or B are detected
simultaneously for 10 minutes continuously
after 6 minutes past from compressor startup
(including the thermostat indication or recov-
U2
ery from defrosting).
(TH4: 1102)
<Condition A>
• Heating mode
(TH33: 1132)
• When discharge superheat is less than 70°C.
• When the TH6 temp is more than the
value obtained by TH7−5°C.
• When the condensing temp of TH5 is
less than 35°C.
<Condition B>
• During compressor operation (Cooling
and Heating)
• When discharge superheat is less than
80°C in Cooling.
• When discharge superheat is less than
90°C in Heating.
• When condensing temp of TH6 is more
than −40°C. (In Cooling only.)
Abnormal if comp. surface temperature
thermistor (TH33) exceeds 120°C or 110°C
(ZM60-140), 117°C or 110°C (ZM200/250)
continuously for 5 minutes.
Open/short circuit of discharge
temperature thermistor (TH4) / comp.
surface thermistor (TH33)
Abnormal if open (−20°C or less) or
short (217°C or more) is detected during
U3
compressor operation.
(TH4: 5104)
(Detection is inoperative for 10 minutes
(TH33: 5132)
of compressor starting process and for 10
minutes after and during defrosting.)
OCH771
Cause
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 or TRS) on out-
door controller board
5 Disconnection or contact failure of
63H or TRS connection
6 Defective outdoor controller board
7 Defective action of linear expan-
sion valve
8 Malfunction of fan driving circuit
9 Overheated compressor operation
caused by shortage of refrigerant
(ZM200/250)
) Defective operation of stop valve
(ZM200/250)
1 Overheated compressor operation
caused by shortage of refrigerant
2 Defective operation of stop valve
3 Defective thermistor
4 Defective outdoor controller board
5 Defective action of linear expan-
sion valve
1 Disconnection or contact failure
of connector (TH4, TH33) on the
outdoor controller circuit board
2 Defective thermistor
3 Defective outdoor controller
circuit board
41
Judgment and action
1−6 Check indoor unit and repair defect.
7 Check if stop valve is fully open.
8 Check piping and repair defect.
9−2 Check outdoor unit and repair defect.
3 Check the detected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool: Refer
to "10-9. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
4−6 Turn the power off and check if F5 is
displayed when the power is turned on
again.
When F5 is displayed, refer to
"Judgment and action" for F5.
7 Check linear expansion valve.
Refer to "10-5. HOW TO CHECK THE
PARTS".
8 Replace outdoor controller board.
9 Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
(ZM200/250)
) Check if stop valve is fully open.
(ZM200/250)
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
displayed when the power is on again.
When U3 is displayed, refer to "Judgment
and action" for U3.
5 Check linear expansion valve.
Refer to "10-5. HOW TO CHECK THE
PARTS".
1 Check connection of connector (TH4, TH33)
on the outdoor controller circuit board. Check
breaking of the lead wire for thermistor TH4, TH33).
Refer to "10-8. TEST POINT DIAGRAM".
2 Check resistance value of thermistor (TH4,
TH33) or temperature by microprocessor.
(Thermistor TH4, TH33: Refer to "10-5. HOW
TO CHECK THE PARTS".)(SW2 on A-Control
Service Tool: Refer to "10-9. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".)
3 Replace outdoor controller board.