14
Rollout Protection Control
The rollout protection device opens, cutting power to
the gas valve, if the flames from the burners are not
properly drawn into the heat exchanger. The rollout
protection device is located on the burner bracket. The
reason for elevated temperatures at the control should
be determined and repaired prior to resetting this manual
reset control.
WARNING
T
O AVOID PROPERTY DAMAGE, PERSONAL INJURY OR DEATH DUE TO FIRE
OR EXPLOSION, A QUALIFIED SERVICER MUST INVESTIGATE THE REASON FOR
THE ROLLOUT PROTECTION DEVICE T O OPEN BEFORE MANUALLY RESETTING
THE ROLLOUT PROTECTION DEVICE.
Rollout Protection
Rollout Protection on Burner Bracket
Secondary Limit Control
The secondary limit control is located on the top of the
blower scroll assembly. This control opens when elevated
temperatures are sensed. Elevated temperatures at the
control are normally caused by blower failure. The reason
for the opening should be determined and repaired prior
to resetting.
If the power to the unit is interrupted during the heating
cycle, it may cause the secondary limit to trip. Once the
blower compartment temperature drops below the limit
reset temperature, the limit will automatically reset.
Secondary
Control Limit
Back of Unit
Secondary Limit Control
Pre-Operation Checks
1. Close the manual gas valve external to the unit.
2. Turn off the electrical power supply to the unit.
Cooling
1.
Thermostat calls for cooling. The compressor and
outdoor fan are energized.
Two-Stage Models:
If the thermostat call is for low stage cooling, the
compressor and outdoor fan are energized at low
stage. If the thermostat call is for high stage cooling,
the compressor and outdoor fan are energized at high
stage.
2. Approximately seven seconds later, the indoor fan
starts.
3. The unit will deliver cooling to the conditioned space
until the thermostat is satisfied.
4. The compressor and outdoor fan will be de-energized
when the thermostat opens.
5. The indoor fan continues to run for approximately 60
seconds after the thermostat is satisfied.
Two-Stage Models:
The fan runs at low cool speed for the off delay period.
This allows additional cooling from the indoor coil to
be transferred to the conditioned space. Then, the
indoor fan stops.
NOTE:
A 180-second anti-short cycle is integral to the control
and prevents recycling of the compressor.
Fan Only
1. Thermostat calls for FAN ONLY by energizing “G”.
2. Approximately seven seconds later, the indoor fan
starts.
Two-Stage Models:
Indoor fan is energized at low heat speed.
3. The indoor fan continues to run for approximately 60
seconds after “G” is de-energized.
Two-Stage Models:
The indoor fan is immediately de-energized once the
thermostat “G” is de-energized.
STARTUP, ADJUSTMENTS, AND CHECKS
Heating Startup
This unit is equipped with an electronic ignition device to
automatically light the main burners. It also has a power
vent blower to exhaust combustion products.
On new installations, or if a major component has been
replaced, the operation of the unit must be checked.
Check unit operation as outlined in the following
instructions. If any sparking, odors, or unusual sounds
are encountered, shut off electrical power and recheck for
wiring errors, or obstructions in or near the blower motors.
Duct covers must be removed before operating unit.
