5. The gas valve deenergizes. The induced draft blower
continues operation for a 29-second post-purge.
6. ignition control begins timing the HEAT FAN OFF delay.
There is an adjustable HEAT FAN OFF delay of
approximately 120/135/150 seconds (factory set at 150).
After the HEAT FAN OFF delay time has elapsed, the blower
will deenergize. This allows any additional heat in the heat
exchanger to be transferred to the conditioned space.
COOLING
1. Thermostat calls for cooling. The compressor and outdoor
fan are energized.
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 deenergized when
the thermostat opens.
5. The indoor fan continues to run for approximately 60
seconds after the thermostat is satisfied. This allows
additional cooling from the indoor coil to be transferred to
the conditioned space. Then, the indoor fan stops.
NOTE: A180-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.
3. The indoor fan continues to run for approximately 60
seconds after "G" is deenergized.
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.
Heat Anticipator Setting
Set the heat anticipator on the room thermostat to 0.4 amps to
obtain the proper number of heating cycles per hour and to
prevent the room temperature from overshooting the room
thermostat setting.
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.
TO AVOID PROPERTY DAMAGE, PERSONAL INJURY OR DEATH DUE TO FIRE
OR EXPLOSION, A QUALIFIED SERVICER MUST INVESTIGATE THE REASON FOR
THE ROLLOUT PROTECTION DEVICE TO OPEN BEFORE MANUALLY RESETTING
THE ROLLOUT PROTECTION DEVICE.
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 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.
3. Set the room thermostat to its lowest possible setting.
4. Remove the heat exchanger door on the side of the unit by
removing screws.
5. This unit is equipped with an ignition device which
automatically lights the main burner. DO NOT try to light
burner by any other method.
6. Move the gas control valve switch to the OFF position. Do
not force.
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