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3-4
12PHR-N
Item
Mode
Control operation
When resistance
is low (temperat-
ure judged higher
than actual)
Short-circuit
When resistance
is high (temperat-
ure judged lower
than actual)
Open-circuit
Compressor
chamber thermistor
(TH1)
Cooling
Dehumidifying
Heating
Expansion
valve control
and compressor
protection
Compressor
operates, but room
does not become
cool or warm
(expansion valve is
open).
Compressor high
temperature error
indication.
Layer short-
circuit or open-
circuit may result
in compressor in
normal operation.
Outdoor unit
thermistor open-
circuit error
indication.
Heat exchanger
thermistor (TH2)
Cooling
Dehumidifying
Outdoor unit
heat exchanger
overheat
prevention
Compressor
operates at low
speed or stops.
Outdoor unit
thermistor short-
circuit error
indication.
Normal operation.
Outdoor unit
thermistor open-
circuit error
indication.
Heating
Expansion valve
control
Defrosting
Defrosting
operation is not
activated as
needed, and frost
accumulates
on outdoo r unit
(expansion valve is
closed).
Outdoor unit
thermistor short-
circuit error
indication.
Defrosting
operation
is activated
unnecessarily,
and room does
not become warm
(expansion valve is
open).
Outdoor unit
thermistor open-
circuit error
indication.
Outside air
temperature
thermistor (TH3)
Auto
Operation mode
judgment
Cooling mode is
activated even if
room temperature
is low.
Outdoor unit
thermistor short-
circuit error
indication.
Heating mode is
activated even if
room temperature
is high.
Outdoor unit
thermistor open-
circuit error
indication.
Cooling
Dehumidifying
Operation not
affected
Normal operation.
Outdoor unit
thermistor short-
circuit error
indication.
Normal operation.
Outdoor unit
thermistor open-
circuit error
indication.
Heating
Rating control
Defrosting
Defrosting
operation
is activated
unnecessarily.
Outdoor unit
thermistor short-
circuit error
indication.
Defrosting
operation is not
activated, and frost
accumulates on
outdoor unit.
Outdoor unit
thermistor open-
circuit error
indication.
Suction pipe
thermistor (TH4)
Cooling
Dehumidifying
Expansion valve
control
Compressor
operates, but room
does not become
cool (expansion
valve is open).
Outdoor unit
thermistor short-
circuit error
indication.
Frost accumulates
on evaporator inlet
section, and room
does not become
cool (expansion
valve is closed).
Outdoor unit
thermistor open-
circuit error
indication.
Heating
Expansion valve
control
Compressor
operates, but room
does not become
warm (expansion
valve is open).
Outdoor unit
thermistor short-
circuit error
indication.
Frost accumulates
on expansion valve
outlet section,
and room does
not become warm
(expansion valve is
closed).
Outdoor unit
thermistor open-
circuit error
indication.
2-way valve
thermistor (TH5)
Cooling
Dehumidifying
Expansion valve
control
Frost accumulates
on indoor unit
evaporator and
room does not
become cool
(expansion valve is
closed).
Outdoor unit
thermistor short-
circuit error
indication.
Compressor
operates, but room
does not become
cool (expansion
valve is open).
Outdoor unit
thermistor open-
circuit error
indication.
Heating
Operation not
affected
Normal operation.
Outdoor unit
thermistor short-
circuit error
indication.
Normal operation.
Outdoor unit
thermistor open-
circuit error
indication.
2. Outdoor unit
12PHR-N_S530612PHRN.indd 4
2013/8/7 15:42:14
Summary of Contents for 12PHR-N
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