To avoid personal injury or death due to electrical shock,
do not remove any internal compartment covers or
attempt any adjustment. Contact a qualified servicer at
once if an abnormal flame should develop.
The burner flames should be inspected with the burner
compartment door installed. Flames should be stable, quiet, soft,
and blue (dust may cause orange tips but they must not be
yellow). Flames should extend directly outward from the burners
without curling, floating, or lifting off. Flames must not impinge on
the sides of the heat exchanger firing tubes.
Check the burner flames for good adjustment, a stable, soft and
blue flame that is not curling, floating or lifting off.
Auxiliary Limit Control
Auto reset limits are located on or near the blower. To access this
auxiliary limit, disconnect the electrical power and remove the
blower door. The auxiliary limit control is designed to prevent
furnace operation in case of main blower failure on horizontal
It may also open if the power supply is interrupted while the
furnace is firing. The auxiliary limit control is suitable for both
horizontal right and horizontal left installations. Regardless of
airflow direction, it does not need to be relocated.
Circulator Blower Speeds
Disconnect ALL power before servicing.
Multiple power sources may be present.
Failure to do so may cause property damage,
personal injury or death.
This furnace is equipped with a PSC circulator blower motor. This
blower provides ease in adjusting blower speeds. Refer to the
Blower Performance Data chart for proper selection of heating
and cooling speeds.
The cooling blower speed is shipped set on HIGH. High heat
ships on MEDIUM and low heat is shipped on MEDIUM-LO.
These blower speeds should be adjusted by the installer to
match the installation requirements so as to provide the correct
heating temperature rise and the correct cooling CFM.
To adjust the circulator blower speed, proceed as follows:
1. Turn OFF power to the furnace.
2. Select the heating and cooling blower speeds that match the
3. Relocate desired motor leads to the circulator blower heat
4. Connect all unused blower motor leads to the "PARK"
5. Turn on power to furnace.
6. Verify the proper temperature rise as outlined in "Temperature
NOTE: Items in this section refer to the air circulator blower fan,
not the induced draft blower. The induced draft blower timing
sequence is not adjustable. The circulator blower fan timing is
adjustable only on models with optional "heating fan OFF delay"
adjustment pins or switches. It is NOT adjustable in any other
As shipped, the circulator blower fan will remain on for
150 seconds after the gas control valve closes. When a call for
cooling occurs, the circulator fan comes on and remains on for
45 seconds after the call for cooling ends. During normal heating
operation, the circulator fan will come on approximately
34 seconds after the gas control valve opens.
Switch viewed in an upflow installation.
installation requirements from the airflow table in the Product
Data Book applicable to your model. Please contact your
distributor for the applicable product data book.
and cool speed terminals on the integrated control module.
Terminals are identified as LO HEAT, HI HEAT and COOL
(hot). If a heating speed and the cooling speed are the same,
a jumper wire must be used between the heat and cool
terminals on the integrated control module. Any leads not
connected to the "PARK" terminals must be taped.
Circulator Blower Fan Timing Adjustment