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SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF,
SHUT OFF THE MANUAL GAS VALVE TO THE APPLIANCE BEFORE SHUT-
TING OFF THE ELECTRICAL SUPPLY. FAILURE TO DO SO CAN RESULT
IN AN EXPLOSION OR FIRE CAUSING PROPERTY DAMAGE, SEVERE
PERSONAL INJURY OR DEATH!
WARNING
BURNERS
Burners for these units have been designed so that eld adjustment is not required.
Burners are tray-mounted and accessible for easy cleaning when required.
MANUAL RESET OVERTEMPERATURE CONTROL
Four manual reset overtemperature controls are located on the burner shield. These
devices senses blockage in the heat exchanger or insufcient combustion air. This
shuts off the main burners if excessive temperatures occur in the burner compart-
ment.
Operation of this control indicates an abnormal condition. Therefore, the unit should
be examined by a qualied installer, service agency, or the gas supplier before being
placed back into operation.
PRESSURE SWITCH
This furnace has two sets of pressure switches for sensing a blocked exhaust or
a failed induced draft blower. They are normally open and close when the induced
draft blower starts, indicating air ow through the combustion chamber.
LIMIT CONTROL
The supply air high temperature limit cut-off is set at the factory and cannot be
adjusted. It is calibrated to prevent the air temperature leaving the furnace from
exceeding the maximum outlet air temperature.
IMPORTANT: Replace this control only with the identical replacement part.
VI. COOLING SECTION OPERATION
COOLING MODE
A. Call for rst stage cooling
1. Zone thermostat contacts close and a call for cooling is initiated.
2. Inputs ‘Y1’ and ‘G’ to the control are energized.
3. Control senses ‘Y1’ and ‘G’. After 1 sec. delay, control energizes indoor blower
and rst stage compressor.
4. Control enters normal operating loop where all inputs are continuously checked.
5. Zone thermostat is satised.
6. Control de-energizes indoor blower relay after 80 second indoor blower delay off.
7. Control in the stand by mode with solid red LED.
DO NOT JUMPER THIS DEVICE! DO NOT RESET THE OVER TEMPERATURE
CONTROL WITHOUT TAKING CORRECTIVE ACTION TO ASSURE THAT AN
ADEQUATE SUPPLY OF COMBUSTION AIR IS MAINTAINED UNDER ALL
CONDITIONS OF OPERATION. FAILURE TO DO SO CAN RESULT IN CARBON
MONOXIDE POISONING OR DEATH. REPLACE THIS CONTROL ONLY WITH
THE IDENTICAL REPLACEMENT PART.
WARNING
!
DO NOT JUMPER THIS DEVICE! DOING SO CAN CAUSE A FIRE OR EXPLO-
SION RESULTING IN PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
WARNING
!
!
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