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XPG15 SERIES
HEATING OPERATING MODE ROOM THERMOSTAT DEMAND FOR Y1 WITH OUTDOOR TEMPERATURE
BELOW 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
X
X
X
DEMAND DEFROST CONTROL INTERNAL RELAY CONTACT STATUS
1. K1 relay contact remain closed.
2. K2 relay contact close and output 24VAC to
RL
output to energize K229 field installed relay.
3. K2 relay contact close and energize reversing valve.
4. K3 relay contact open and de−energize compressor contactor due to outdoor temperature being below 32ºF (0ºC). Heat
pump goes into inactive mode.
5. K4 relay contact close and send 24VAC to
W out
terminal. Gas furnace will satisfy
Y1
heat demands.
6. 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
operation.