Mitsubishi Electric PSA Series Service Manual page 21

Abnormal point and detection method
Check Code
Indoor/outdoor unit communication
error (Transmitting error)
Abnormal if "1" receiving is detected 30
E7
times continuously though indoor controller
board has transmitted "0".
Indoor controller board
Abnormal if data cannot be read normally
FB
from the nonvolatile memory of the indoor
(Fb)
controller board.
Remote controller control board
1 Abnormal if data cannot be read nor-
mally from the nonvolatile memory of
E1
the remote controller control board.
or
(Check code: E1)
E2
2 Abnormal if the clock function of remote
controller cannot be operated normally.
(Check code: E2)
Connection error
Abnormal if a connection of indoor unit and
outdoor unit which uses different refrigerant
is detected.
EE
Refrigerant sensor error
Abnormal if refrigerant sensor cannot
detect errors normally.
FH
Refrigerant leakage
Abnormal if refrigerant leakage detected by
a refrigerant sensor.
FL
Fan motor trouble
PB
(Pb)
Abnormal refrigerant circuit
During Cooling, Dry, or Auto Cooling
operation, when the following are
regarded as failures when detected for
one second.
a) The compressor continues to run for 30
or more seconds.
b) The liquid pipe temperature or the
PL
condenser/evaporator temperature is
75°C or more.
These detected errors will not be
cancelled until the power source is
reset.
OCH724
Cause
1 Defective transmitting receiving cir-
cuit of indoor controller board
2 Noise has entered into power sup-
ply.
3 Noise has entered into outdoor
control wire.
1 Defective indoor controller board
1 Defective remote controller
1 Unauthorized connection of indoor
unit and outdoor unit
Connections other than below com-
bination are not authorized;
Outdoor unit: Models with R32 refrigerant
Indoor unit: Floor standing type indoor
unit (PSA-KA)
1 The refrigerant sensor mounted on
the indoor unit does not work.
2 The refrigerant sensor is not
connected properly or the wire is
broken.
1 Refrigerant leaks from the piping or the
heat exchanger in the indoor unit.
2 The following items are used around the
indoor unit.
• Spray (LP gas including Freon, and whose
main ingredient is propane and butane)
• Aerosol insecticide (including ethanol)
• Air spray painting (including dichloromethane)
• Charcoal (charcoal fire)
• Chemicals (such as ethanol)
1 Defective fan motor
2 Defective indoor controller board
1 Abnormal operation of 4-way valve
2 Disconnection of or leakage in
refrigerant pipes
3 Air into refrigerant piping
4 Abnormal operation (no rotation) of
indoor fan
· Defective fan motor
· Defective indoor control board
5 Defective refrigerant circuit (clogging)
21
Countermeasure
1–3 Turn the power off, and on again to
check. If abnormality occurs again,
replace indoor controller board.
1 Replace indoor controller board.
1 Replace remote controller.
1 Alter the connection referring to the
combination as shown in the "cause"
column.
12 Turn the power off, check the connec-
tion of some parts such as connectors
and turn the power on again.
When the error has not been cleared,
replace the refrigerant sensor.
• Turn off the power after FAN operation is
finished. (FAN operation continues for 8
hours.)
• Check the indoor unit to detect the part
where refrigerant leaks.
• Repair the part where refrigerant leaks.
• Turn on the power again.
• Replace the refrigerant sensor if the
problem is not fixed.
12 Refer to "9-5-2. DC Fan motor (FAN
MOTOR/INDOOR CONTROLLER
BOARD)".
1 When this error occurs, be sure to
replace the 4-way valve.
2 Check refrigerant pipes for
disconnection or leakage.
3 After the recovery of refrigerant, vacuum
dry the whole refrigerant circuit.
4 Refer to section "9-5-2. DC Fan
motor (FAN MOTOR/INDOOR
CONTROLLER BOARD)".
5 Check refrigerant circuit for operation.
To avoid entry of moisture or air
into refrigerant circuit which could
cause abnormal high pressure, purge
air in refrigerant circuit or replace
refrigerant.