SystemAir fantech VHR 200R Manuel D'installation page 17

WIRING DIAGRAM (CONT'D)
WIRING DIAGRAM TO
FURNACE
FOR A FURNACE
CONNECTION TO
A COOLING SYSTEM:
On some newer furnaces and older
thermostats, energizing the R and
G terminal at the furnace has the
effect of energizing the Y at the
thermostat and thereby turning on
the cooling system. If you identify this
type of thermostat, you must use the
"Alternate Furnace Interlock Wiring"
As per building codes and installation requirements for combustion appliances:
Air return ducts, or openings for air return, should not be placed in enclosed spaces containing combustion
appliances that are subject to spillage.
Standard Accessory Control Contact
Standard Furnace Interlock Wiring
W
FOUR
WIRE
TWO WIRE
heating only
W
R
G
C
Y
FURNACE
24-VOLT
TERMINAL BLOCK
Alternative Accessory Control Contact
Alternate Furnace Interlock Wiring
W
FOUR
WIRE
TWO WIRE
heating only
W
R
WIRE JOINT
G
C
Y
FURNACE
24-VOLT
TERMINAL BLOCK
THERMOSTAT
TERMINALS
R G Y
TWO
WIRE
THERMOSTAT
TERMINALS
R G
Y
TWO
WIRE
17
COOLING SYSTEM
COOLING SYSTEM