12
12
INSTALLATION
TERMINAL
FUNCTION
LABELS
(HEAT PUMP)
COMMENTS
R
24V AC supply
Hot wire of 24VAC transformer. Powers the thermostat & system.
Y1
Compressor stage 1
Activates the 1st stage compressor. (Heat or Cool for Heat Pumps)
W2
Auxiliary heating
Activates the 2nd stage (auxiliary) heating when required.
E
Emergency heating
Activates Emergency heating ONLY when the System Switch is in Emergency (em) Mode.
O
Reversing valve
Activates reversing valve in COOL mode. ALWAYS ON in COOL MODE.
(cooling mode)
B
Reversing valve
Activates reversing valve in HEAT mode. ALWAYS ON in HEAT MODE.
(heating mode)
G
Fan
Activates the system Fan. (Can be Auto, On, or Program controlled)
L
System monitor
Activates System Check LED on the front of thermostat.
(Controlled by the system, not the thermostat.)
C
24V AC common
Common wire of 24V AC transformer. REQUIRED for thermostat operation.
TABLE A – TERMINAL DESCRIPTIONS
41652_model44760_web.pmd
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13
TABLE B
HEAT PUMP CROSS-REFERENCE CHART
NOTE:
If your heat pump thermostat does not have an E wire, use the provided jumper wire to connect the E terminal to
the W2 terminal, as shown in three examples above. Refer to the Wiring Diagram on page 52.
EXAMPLES OF DIFFERENT SYSTEM TERMINALS
HUNTER
BRYANT,
RHEEM-
TRANE,
TERMINALS
CARRIER
COLEMAN
COMFORTMAKER
PAYNE
RUUD
WEATHERTRON
YORK
LENNOX (1)
LENNOX (2)
R
R
R
R
R
R
R
R
R
V-VR
Y1
Y or Y1
Y
Y
Y
Y
Y
Y
Y
M
W2
W2
W2
W1
W2
W2
W
W
W1
Y
E
E
E
jumper
E
E
X2
jumper
E
E
to W2
to W2
O
O
O
O
O
O
O
R
B
B
B
G
G
G
G
G
G
G
G
G
F
L
L or F
L
L or X
L
L
X
L
C
C
X
C, X, X1
C, C1, X1
X
B
B
C
X
Note: W2 wires
Note: T wire
no connection
no connection
