5. E
C
LECTRICAL
ONNECTION TO THE
Never connect a 120-volt AC circuit to the terminals of the furnace interlock (standard wiring). Use only the low
voltage class 2 circuit of the furnace blower control.
For a furnace connected to a cooling system:
On some older thermostat, energizing the "R" and "G" terminals at the furnace has the effect of energizing "Y" terminal at the thermostat
and thereby turning on the cooling system. If you identify this type of thermostat, you must use the A
S
F
TANDARD
W
R
G
FOUR
WIRES
TWO WIRES
heating only
W
R
G
C
Y
FURNACE
24-VOLT
TERMINAL BLOCK
VE0108A
F
URNACE
I
W
URNACE
NTERLOCK
IRING
THERMOSTAT
Y
TERMINALS
TWO WIRES
COOLING SYSTEM
!
WARNING
A
LTERNATE
4 WIRES
2 WIRES
heating only
W
R
R
G
C
Y
Y
FURNACE
24-VOLT
TERMINAL BLOCK
15
F
LTERNATE
URNACE
F
I
URNACE
NTERLOCK
THERMOSTAT
W
R
G
Y
TERMINAL
wiring
nuts
NO
NC
C
2 WIRES
I
W
.
NTERLOCK
IRING
W
IRING
COOLING SYSTEM