Technical data

26
W
R
G
C
Y
W
R G
Y
Standard Furnace Interlock Wiring
THERMOSTAT
TERMINALS
FURNACE
24-VOLT
TERMINAL BLOCK
FOUR
WIRE
TWO WIRE
heating only
TWO
WIRE
COOLING SYSTEM
HRV
ELECTRONIC BOARD
W
R
G
C
Y
W
R G
Y
Alternate Furnace Interlock Wiring
THERMOSTAT
TERMINALS
FURNACE
24-VOLT
TERMINAL BLOCK
FOUR
WIRE
TWO WIRE
heating only
TWO
WIRE
COOLING SYSTEM
HRV
ELECTRONIC BOARD
WIRE JOINT
ELECTRICAL CONNECTIONS (CONT'D)
Caution:
• Never connect a 120 volt AC
circuit to the terminals of the
Accessory Control Contacts.
Only use the low voltage class
2 circuit of the furnace blower
control.
For a Furnace Connected to a
Cooling System:
• On some older thermostats,
energizing the R and G termi-
nals at the furnace has the
effect of energizing Y at the
thermostat and thereby turn-
ing on the cooling system. If
you identify this type of ther-
mostat, you must use the
“Alternate Furnace
Interlock Wiring”.
PRACTICAL TIPS
ELECTRICAL CONNEC-
TION TO A FURNACE
Standard Accessory Control Contact
Alternate Accessory Control Contact