Johnson Controls HICM008B21S - 4.4.3.3 Thermistor Details; Thermistor Locations and Types; Indoor Suction Air Thermistor Functionality

(Main Parts)
MAINTENANCE
4-24
SM-18003
4.4.3.3 Thermistor
(1) PositionofThermistor
(2) ThermistorforIndoorSuctionAir
Temperature(ForRoomTemperature
Control)
 Theroomtemperatureiscontrolledbythe
thermistorforindoorsuctionairtemperature
detectingthetemperatureatthesuctionair
inlet of the indoor unit.
Thesettingtemperatureisindicatedon
theL.C.D.ofthewiredcontrollerswitchby
number.
Adjustthesettingtemperatureforprevention
fromexcessivecoolingandheating.
Itisrecommendedtosetthetemperatureas
follows;
EconomicalCoolingOperation:81
o
F(27
o
C)to84
o
F (29
o
C)/EconomicalHeatingOperation:64
o
F
(18
o
C)to68
o
F (20
o
C)
Theresistancecharacteristicsofthermistorisshownintheabovegure.
ATTENTION:
Thethermo-offvalueoftheindoorunitairinletthermistorissetatthetemperaturehigherthanthevalue
indicatedonthewiredcontrollerswitchby7
o
F (4
o
C)andthemaximumis86
o
F (30
o
C),becausethesuction
airtemperatureduringheatingoperationhasatendencytobecomehigherthanthatoftheoccupiedzone,
intendingcomfortableheatingoperation.
(3) ThermistorforIndoorDischargeAirTemperature(ForDischargeAirTemperatureControl)
 Thethermistorforindoordischargeairtemperatureisutilizedforthecontrolofpreventionfromcoldair
dischargeinheatingoperation,etc.
Theresistancecharacteristicsofthermistorisshownintheabovegure.
(4) ThermistorforLiquidPipeTemperatureofIndoorHeatExchanger
Theresistancecharacteristicsofthermistorisshownintheabovegure.
(5) ThermistorforGasPipeTemperatureofIndoorHeatExchanger
Theevaporatingtemperatureinheatingoperationisdetected.
Theresistancecharacteristicsofthermistorisshownintheabovegure.
When the temperature of the heat exchanger is below 32
o
F (0
o
C),
thermostat is turned OFF automatically and over 57
o
F (14
o
C),
thermostat is turned ON again.
Prevention from freezing
onto the heat exchanger in
COOL and DRY operation.
When the temperature of the heat exchanger is below 32
o
F (0
o
C),
thermostat is turned OFF automatically and over 57
o
F (14
o
C),
thermostat is turned ON again.
Prevention from freezing
onto the heat exchanger in
COOL and DRY operation.
0
10
20
30
40
50
60
70
80
5
(-15)
14
(-10)
23
(-5)
0
(0)
41
(5)
50
(10)
59
(15)
68
(20)
77
(25)
86
(30)
95
(35)
104
(40)
113
(45)
122
(50)
131
(55)
140
(60)
82
61
46
35
27
20.5
16
12.5
10
8
5.3
3.6
2.5
90
Ambient Temperature (
o
C)
Thermistor
Resistance
Thermistor Characteristics
●MiniCassette
Inlet Air Thermistor
(THM1)
Outlet Air Thermistor
(THM2)
Liquid Pipe Thermistor
(Freeze Protection)
(THM3)
Gas Pipe Thermistor
(THM5)