Abnormal Low Pressure Or Low Pressure Sensor Wire Disconnected; 52C Abnormal; Error Display E49; Error Display E52 - Mitsubishi Heavy Industries FDCA Series Technical Manual

Error display
11
Indoor unit
Red LED
Green LED Keeps flashing
Is the low pressure sensor
connector's connection
(sensor side, PCB side) OK?
YES
Is the amount of refrigerant appropriate?
Is the refrigeration circuit abnormal?
● Display Conditions
The compressor stops if the low pressure sensor detects a pressure of 0.079 (0.120) MPa or lower con-
tinuously for 15 seconds.
After a 3-minute delay, the compressor restarts, but if this occurs 3 times within 60 minutes.
Note (1) Values in ( ) show in the case where 10 minutes or longer have passed since the compressor started.
[Gas low error] (Only case of FDCA801, 1001 type)
Indoor unit
Red LED
Green LED Keeps flashing
Is the service valve fully open?
Are the
indoor heat exchanger and return
air temperature thermistor connector
connections OK?
Are the
characteristics of the indoor heat
exchanger and return air temperature
thermistors OK?
Is the low pressure during
operation appropriate?
Indoor control PCB is faulty.
(Indoor heat exchanger and return air tem-
perature thermistors input circuits are faulty.)
Error display :
12
Indoor unit
Red LED
Green LED Keeps flashing
Is E52
Cooling operation
E52 Heating operation
displayed in the remote
controller's
screen?

[Abnormal low pressure or low pressure sensor wire disconnected]

e49
:
(Only case of FDCA801, 1001 type)
Stays OFF Red LED
Green LED
NO
NO
Change of outdoor
unit PCB
Stays OFF Red LED
Green LED
NO
YES
NO
YES
NO
YES
NO
YES
Replace it.
e52

[52C Abnormal]

Stays OFF Red LED
Green LED
YES
The 52C is abnormal.
Outdoor unit
1 time flash
Keeps flashing
Correction
Replacement low
pressure sensor
NO
Did it retun to normal?
Outdoor unit
1 time flash
Keeps flashing
Open it fully.
Correction
The indoor heat exchanger and
return air temperature thermistor
are faulty. Replace them.
Charge with refrigerant.
Outdoor unit
Lights contiously
Keeps flashing
151
- -
Abnormal pressure detection
CM operation
CM stop
0.079 (0.120) 0.128
Low pressure (Mpa)
Indoor unit heat exchanger
thermistor (Th R),
I-
Return air thermistor (Th A)
I-
Resistance temperature characteristics
15
10
5kΩ at 25°C
5
0 10 20 30
Temperature (°C)
40 50