Abnormalities Detected While Unit Is Operating - Mitsubishi Electric PUHZ-P200YKA.UK Service Manual

<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 (4.15
MPa) operated during compressor operation.
U1
(1302)
High comp. surface temperature
1. A bnormal if comp. surface temperature
thermistor (TH32) exceeds 125°C or 110°C
continuously for 5 minutes.
Abnormal if condenser/evaporator temperature
thermistor (TH5) exceeds 40°C during
defrosting and comp. surface temperature
thermistor (TH32) exceeds 110°C.
2. Abnormal if discharge superheat
( Cooling: TH32−TH5 / Heating: TH32−TH6)
increases.
All the conditions in A or B are detected
simultaneously for 10 minutes continuous-
ly after 6 minutes past from compressor
start-up (including the thermostat indica-
tion or recovery from defrosting).
<Condition A>
U2
• Heating mode
• W hen discharge superheat is less than 70°C.
(TH32:1132)
• W hen the TH6 temp is more than the
value obtained by TH7−5:.
• W hen the condensing temp of TH5 is
less than 35:.
<Condition B>
• D uring compressor operation (Cooling
and Heating)
• W hen discharge superheat is less than
80°C in Cooling.
• W hen discharge superheat is less than
90°C in Heating.
• W hen condensing temp of TH6 is more
than −40:. (In Cooling only.)
3. Abnormal if comp. surface temperature
thermistor (TH32) exceeds 125°C or
110°C continuously for 5 minutes.
Open/short circuit of comp. surface
thermistor (TH32)
Abnormal if open (−20°C or less) or
short (217°C or more) is detected during
compressor operation.
(Detection is inoperative for 10 minutes
U3
of compressor starting process and for 10
(TH32:5132)
minutes after and during defrosting.)
OCH582B
Case
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 con-
troller board
5 Disconnection or contact failure of
63H connection
6 Defective outdoor controller board
7 Defective action of linear expan-
sion valve
8 Malfunction of fan driving circuit
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 (TH32) on the outdoor
controller circuit board
2 Defective thermistor
3 Defective outdoor controller circuit
board
32
Judgment and action
1–6 C heck 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 "10-10. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
4–6 T urn 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 "10-6. HOW TO CHECK THE
PARTS".
8 Replace outdoor controller board.
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 "10-6. HOW TO CHECK THE
PARTS".
1 Check connection of connector (TH32) on
the outdoor controller circuit board. Check
breaking of the lead wire for thermistor
(TH32). Refer to "10-9. TEST POINT
DIAGRAM".
2 Check resistance value of thermistor
(TH32) or temperature by microprocessor.
(Thermistor/TH32: Refer to "10-6. HOW TO
CHECK THE PARTS".)(SW2 on A-Control
Service Tool: Refer to "10-10. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".)
3 Replace outdoor controller board.