Installation manual 2120 Dry contact for thermostat
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Setting and using method
Thermostat
LG does not supply this section
(Field supply)
LOW
MIDDLE
HIGH
LLL
Operation
Thermal
FAN
HEAT
COMM
L
N
C
AC 24 V
RYGB
n For heat pump thermostat with B terminal signal input
Thermostat Fan & System Switch Input
IDU Response
[Mode / Thermal / Fan]
FAN
[Auto / On]
MODE
[Cool / Heat / Off]
Operation
Thermal
[Y]
FAN
[G]
HEAT
[B]
- - - 0 - - - Disable Operation
Auto
OFF - 1 0 0 0 Off
Cool
RT > SP 1 1 0 0 Cool / On / On
RT < SP 1 0 0 0 Off
Heat
RT < SP 1 1 0 1 Heat/ On/On
RT > SP 1 0 0 1 Off
ON
OFF - 1 0 1 0 Fan/ Off/ On
Cool
RT > SP 1 1 1 0 Cool/ On/ On
RT < SP 1 0 1 0 Fan/ Off/ On
Heat
RT < SP 1 1 1 1 Heat/ On/ On
RT > SP 1 0 1 1 Fan/ Off/ On
Notes
• Thermostats that close contacts "O" or "B" during Cool or Heat call only have not been verified. "O"
and/or "B" contact closure must be maintained during respective cycle / mode selection.
• IDU Fan logic, depending on model selected, may delay IDU fan operation momentarily during a cold
start heat call. This function allows IDU coil to warm up prior to operating fan in some IDU models.
• Thermostats that use resistive anticipation are not supported at this time.
• Verify documentation of desired thermostat so that the logic is same as shown in the table above.
Setting and using method
Thermostat
LG does not supply this section
(Field supply)
LOW
MIDDLE
HIGH
L
L
N
LL
Operation
Thermal
FAN
COOL
COMM
C
AC 24 V
RYGO
n For heat pump thermostat with O terminal signal input
Thermostat Fan & System Switch Input
IDU Response
[Mode / Thermal / Fan]
FAN
[Auto / On]
MODE
[Cool / Heat / Off]
Operation
Thermal
[Y]
FAN
[G]
COOL
[O]
- - - 0 - - - Disable Operation
Auto
OFF - 1 0 0 0 Off
Cool
RT > SP 1 1 0 1 Cool / On / On
RT < SP 1 0 0 1 Off
Heat
RT < SP 1 1 0 0 Heat/ On/On
RT > SP 1 0 0 0 Off
ON
FAN - 1 0 1 0 Fan/ Off/ On
Cool
RT > SP 1 1 1 1 Cool/ On/ On
RT < SP 1 0 1 1 Fan/ Off/ On
Heat
RT < SP 1 1 1 0 Heat/ On/ On
RT > SP 1 0 1 0 Fan/ Off/ On
Notes
• Thermostats that close contacts "O" or "B" during Cool or Heat call only have not been verified. "O"
and/or "B" contact closure must be maintained during respective cycle / mode selection.
• IDU Fan logic, depending on model selected, may delay IDU fan operation momentarily during a cold
start heat call. This function allows IDU coil to warm up prior to operating fan in some IDU models.
• Thermostats that use resistive anticipation are not supported at this time.
• Verify documentation of desired thermostat so that the logic is same as shown in the table above.
※ RT : Room Temperature
※ SP : Set Point
※ RT : Room Temperature
※ SP : Set Point
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