Installer’s Guide
To shut off.
For complete
▲! CAUTION
If this is done during the cold weather months, provi- sions must be taken to prevent
Failure to follow this warning could result in property damage.
Whenever your house is to be vacant, arrange to have someone inspect your house for proper tem- perature. This is very important during freezing weather. If for any reason your furnace should fail to operate damage could result, such as fro- zen water pipes.
SEQUENCE OF OPERATION
Thermostat call for heat
R and W thermostat contacts close signaling the control module to run its
As the induced draft blower comes up to speed, the pressure switch contacts will close and the ignitor warm up period will begin. The ignitor will heat for approxi- mately 20 seconds, then the gas valve is energized to permit gas flow to the burners. The flame sensor con- firms that ignition has been achieved.
After the flame sensor confirms within a 4 second trial period that ignition has been achieved, the delay to fan ON period begins timing. After approximately 45 sec- onds the indoor blower motor will be energized and con- tinue to run during the heating cycle.
When the thermostat is satisfied, R and W thermostat contacts open, the gas valve will close, the flames will extinguish, and the induced draft blower will be
CONTROL AND SAFETY SWITCH ADJUSTMENTS LIMIT SWITCH CHECK OUT
The limit switch is a safety device designed to close the gas valve should the furnace become overheated. Since proper operation of this switch is important to the safety of the unit, it must be checked out on initial
start up by the installer.
To check for proper operation of the limit switches, set the thermostat to a temperature higher than the indi- cated temperature to bring on the gas valve. Restrict the airflow by blocking the return air (disconnecting the indoor blower may trip the inducer limit). When the
furnace reaches the maximum outlet temperature as shown on the rating plate, the burners must shut off. If they do not shut off after a reasonable time and over- heating is evident, a faulty limit switch is probable and the limit switch must be replaced. After checking the operation of the limit control, be sure to remove the pa- per or cardboard from the return air inlet. Refer to Ser- vice Facts for additional instructions.
NOTE TO INSTALLER
Review the following warnings with the owner. Review contents of USER’S INFORMATION MANUAL with the owner.
AIRFLOW ADJUSTMENT
Check inlet and outlet air temperatures to make sure they are within the ranges specified on the furnace rat- ing nameplate. If the airflow needs to be increased or decreased, see the wiring diagram for information on changing the speed of the blower motor.
▲! WARNING
Disconnect power to the unit before removing the blower door.
Failure to follow this warning could result in property damage, personal injury or death.
This unit is equipped with a blower door switch which cuts power to the blower and gas valve causing shut- down when the door is removed. Operation with the door removed or ajar can permit the escape of danger- ous fumes. All panels must be securely closed at all times for safe operation of the furnace.
INDOOR BLOWER TIMING
Heating: The integrated furnace control module con- trols the indoor blower. The blower start is fixed at 45 seconds after ignition. The
ROOM AIR THERMOSTAT
HEAT ANTICIPATOR ADJUSTMENT
Set the thermostat heat anticipator according to the current flow measured, or the settings found in the notes on the furnace wiring diagram (found in the SER- VICE FACTS or inside the furnace casing).
INSTRUCTIONS TO THE OWNERS
In the event that electrical, fuel, or mechanical failures occur, the owner should immediately turn the gas supply off at the manual gas valve, located in the burner compartment. Also turn off electrical power to the furnace and contact the service agency designated by your dealer.
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