IVT AE-X12GR-N Service Manual page 24

AEX12GRN
2. Outdoor unit
Item Mode
Compressor Cooling
chamber ther- Dehumidifying
mistor (TH1) Heating
Heat exchanger Cooling
thermistor (TH2) Dehumidifying
Heating
Outside air tem- Auto
perature ther-
mistor (TH3)
Cooling
Dehumidifying
Heating
Suction pipe ther- Cooling
mistor (TH4) Dehumidifying
Heating
2-way valve ther- Cooling
mistor (TH5) Dehumidifying
Heating
Control opera- When resistance is
tion low (temperature
judged higher than
actual)
Expansion valve Compressor oper-
control and com- ates, but room does
pressor protection not become cool or
warm (expansion
valve is open).
Outdoor unit heat Compressor operates
exchanger over- at low speed or stops.
heat prevention
Expansion valve Defrosting operation
control is not activated as
Defrosting needed, and frost
accumulates on out-
door unit (expansion
valve is closed).
Operation mode Cooling mode is acti-
judgment vated even if room
temperature is low.
Operation not Normal operation.
affected
Rating control Defrosting operation
Defrosting is activated unneces-
sarily.
Expansion valve Compressor oper-
control ates, but room does
not become cool
(expansion valve is
open).
Expansion valve Compressor oper-
control ates, but room does
not become warm
(expansion valve is
open).
Expansion valve Frost accumulates on
control indoor unit evapora-
tor and room does
not become cool
(expansion valve is
closed).
Operation not Normal operation.
affected
Short-circuit
Compressor high
temperature error
indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
Outdoor unit ther-
mistor short-circuit
error indication.
3 – 4
When resistance Open-circuit
is high (tempera-
ture judged lower
than actual)
Layer short-circuit Outdoor unit ther-
or open-circuit may mistor open-cir-
result in compres- cuit error
sor in normal opera- indication.
tion.
Normal operation. Outdoor unit ther-
mistor open-cir-
cuit error
indication.
Defrosting opera- Outdoor unit ther-
tion is activated mistor open-cir-
unnecessarily, and cuit error
room does not indication.
become warm
(expansion valve is
open).
Heating mode is Outdoor unit ther-
activated even if mistor open-cir-
room temperature is cuit error
high. indication.
Normal operation. Outdoor unit ther-
mistor open-cir-
cuit error
indication.
Defrosting opera- Outdoor unit ther-
tion is not acti- mistor open-cir-
vated, and frost cuit error
accumulates on indication.
outdoor unit.
Frost accumulates Outdoor unit ther-
on evaporator inlet mistor open-cir-
section, and room cuit error
does not become indication.
cool (expansion
valve is closed).
Frost accumulates Outdoor unit ther-
on expansion valve mistor open-cir-
outlet section, and cuit error
room does not indication.
become warm
(expansion valve is
closed).
Compressor oper- Outdoor unit ther-
ates, but room does mistor open-cir-
not become cool cuit error
(expansion valve is indication.
open).
Normal operation. Outdoor unit ther-
mistor open-cir-
cuit error
indication.