IVT 12KHR-N Service Manual page 26

12KHR-N
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 resis-
tion tance is low
(temperature
judged higher
than actual)
Expansion valve Compressor
control and com- operates, but
pressor protection room does not
become cool or
warm (expansion
valve is open).
Outdoor unit heat Compressor
exchanger over- operates at low
heat prevention speed or stops.
Expansion valve Defrosting opera-
control tion is not acti-
Defrosting vated as needed,
and frost accumu-
lates on outdoor
unit (expansion
valve is closed).
Operation mode Cooling mode is
judgment activated even if
room tempera-
ture is low.
Operation not Normal operation.
affected
Rating control Defrosting opera-
Defrosting tion is activated
unnecessarily.
Expansion valve Compressor
control operates, but
room does not
become cool
(expansion valve
is open).
Expansion valve Compressor
control operates, but
room does not
become warm
(expansion valve
is open).
Expansion valve Frost accumu-
control lates on indoor
unit evaporator
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-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
Outdoor unit ther-
mistor short-cir-
cuit error
indication.
3 – 4
When resis- Open-circuit
tance is high
(temperature
judged lower
than actual)
Layer short-cir- Outdoor unit ther-
cuit or open-cir- mistor open-cir-
cuit may result in cuit error
compressor in indication.
normal operation.
Normal operation. Outdoor unit ther-
mistor open-cir-
cuit error
indication.
Defrosting opera- Outdoor unit ther-
tion is activated mistor open-cir-
unnecessarily, cuit error
and room does indication.
not become warm
(expansion valve
is open).
Heating mode is Outdoor unit ther-
activated even if mistor open-cir-
room tempera- cuit error
ture is 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 accumu- Outdoor unit ther-
lates on evapora- mistor open-cir-
tor inlet section, cuit error
and room does indication.
not become cool
(expansion valve
is closed).
Frost accumu- Outdoor unit ther-
lates on expan- mistor open-cir-
sion valve outlet cuit error
section, and room indication.
does not become
warm (expansion
valve is closed).
Compressor Outdoor unit ther-
operates, but mistor open-cir-
room does not cuit error
become cool indication.
(expansion valve
is open).
Normal operation. Outdoor unit ther-
mistor open-cir-
cuit error
indication.