The Outdoor Heat Exchanger Temperature Is Too High; The Discharge Gas Temperature Is Too High; Defective Outdoor Unit Heat Exchanger Thermistor - Mitsubishi FDTN208HEN-S Instruction Manual

FDTN-H
4
The outdoor heat exchanger temperature is too high (70°C or over)
Outdoor unit
Red LED 4 time flashes
Green LED Stays OFF
5

The discharge gas temperature is too high.

Outdoor unit
Red LED 5 time flashes
Green LED Stays OFF
Is the
discharge gas ther-
mistror characteristics
normal?
NO
Discharge pipe thermis-
tor replacement
Is the unit
normalized
NO
Defective outdoor unit
PCB Replacement
(Defective discharge gas
thermistor input circuit)
6

Defective outdoor unit heat exchanger thermistor

Outdoor unit
Red LED 1 time flash
Green LED 1 time flash
Is the outdoor
YES
unit heat exchanger
themistor connector
OK?
NO
Repair
282
(1)
Are the heat
exchanger thermistor
Charateristisc
Normal?
NO
Heart exchanger thermistor
replacement
Is the unit
normalized
NO
Defective outdoor unit
PCB Replacement
(Defective heat exchanger
thermistor input circuit)
Discharge gas
Check the unit side.
temperature error?
YES
• Insufficient refrigerant
(At cooling/heating
operation)
• Is it the overload operation?
Error stop
Operable
90°C 135°C
Discharge pipe temp.
Are the outdoor
unit heat exchanger themistor
characteristics OK, is there
any broken wire?
NO
Defective outdoor unit
heat exchanger thermistor
Replacement
(1)
YES Cooling, overload
operation?
Note (1) Outdoor unit heat exchanger thermistor detects
Charge the refrigerant (measure)
Defective outdoor unit PCB
YES
Replacement (Defective
outdoor unit heat exchanger
thermistorinput circuit)
Check the unit side closely
• Is outdoor fan motor operating?
• Is the outdoor unit shortcircuited?
• Is the installation space adequate?
• Is there too much refrigerant?
the state of cooling overload operation.
Error stop
Reset
60°C 70°C
Outdoor unit heat exchanger temperature
Check the unit side.
• During cooling: Is FMo operating?
• During heating: Is FM
operating?
I
Are control valves (both liquid,
gas) fully opened during both
cooling and heating.
• Is the installation space of indoor/
outdoor units adequate?
• Is there any short circuit air flow
for indoor/outdoor units?
Outdoor unit heat exchanger
thermistor (Th R) Resistance
O-
temperature characteristics
15
10
5kΩ at 25°C
5
0°C 10°C 20°C 30°C 40°C
Temperature
Note (1) 22kΩ at -6°C
50°C