5
SECTION III
High voltage connections
Line power 240/1/60 must be brought in to the furnace control compartment via the knockout provided on the right hand or left hand
side of the furnace. The use of any other entry point may result in these high voltage leads coming into contact with low voltage
circuit components resulting in potentially hazardous conditions. Power lines must be connected to the furnace main terminal
block.
Refer to Fig # 5 to determine proper wire sizing. A ground connection is provided in this compartment. Always ensure that the
ground circuit is installed to meet the requirements of all local and national codes.
Fan motor connections.
All furnaces are provided with multi speed direct drive motors or ECM motors.
Furnaces up to and including 23kW outputs are provided with 1/3 hp, 3 speed motors.
27kW furnaces are provided with 3/4hp 4 speed motors. Only 3 speeds are connected to the controller. The fourth speed motor lead,
low speed, is not connected.
Low Voltage
Contained within the control enclosure is the low voltage transformer. This is 240vac primary with 24vac secondary, 40 VA class
2 transformer. It provides power to the furnace controller, thermostat, A/C condenser relay and 24vac external devices. Always
ensure that the load imposed by external devices does not exceed 40 VA.
Fig 2
Low Voltage Control Connections
Terminal
Purpose
G
FAN RELAY
THERMOSTAT INPUT
W
THERMOSTAT INPUT
STAGE 1 HEATING
W2
THERMOSTAT INPUT
STAGE 2 HEATING
R
24 vac OUTPUT TO THERMOSTAT ONLY
Y/Y1
THERMOSTAT INPUT
STAGE 1 COOLING
Y2
THERMOSTAT INPUT
STAGE 2 COOLING
C
24 vac COMMON
OUTPUT TO THERMOSTAT
