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506212−01 11/10
HEATING OPERATING MODE ROOM THERMOSTAT DEMAND FOR Y1 AND W1 WITH OUTDOOR
TEMPERATURE ABOVE 32ºF (OºC)
K1
K2
K2
K3
K4
Operation Mode
ComfortSense®
Gas Furnace
Dedicated Heat Pump (XPG15)
INPUTS/OUT-
PUTS
"
Y1
W1
W2
O
G
E
L
Y1
Y2
W1
W2
G
O
Y1
W
IN
RL/
K229
O
Y1
OUT
W
OUT
Heating Mode (Outside Temperature above 32ºF)
First Stage Heat-
ing (Heat Pump)
X
X
X
X
X
X
Second Stage
Heating (First
Stage Gas Heat)
X
X
X
X
X
X
X
X
X
X
Third Stage Heat-
ing (Second
Stage Gas Heat)
X
X
X
X
X
X
X
X
X
X
X
X
DEMAND DEFROST CONTROL INTERNAL RELAY CONTACT STATUS
1. K1 relay contact remain closed.
2. K2 relay contact (two sets) close and output 24VAC to
RL
output to energize K229 field installed relay.
3. K3 relay contact open and de−energize compressor contactor.
4. K4 relay contact remain closed.
5. K229 relay with normally closed contacts is now open and removes the
Y1
and
G
signals going from the room
thermostat to the furnace control. This allows the furnace to control the indoor blower operation during gas heat
operations.
NOTE When demand defrost control receives
Y1
and
W in
room thermostat demands, the gas furnace will satisfy both
room thermostat demands before cycling OFF.