506941-01
Page 11 of 16
Issue 1148
Filters
Filters are not supplied with the unit. Inspect once a month.
Replace disposable or clean permanent type as necessary.
Do not replace permanent type with disposable.
Motors
Indoor and outdoor fan and vent motors are permanently
lubricated and require no maintenance.
Rollout Switch
The switch is located on the left side of
burner box. In the event of a sustained main burner rollout,
the rollout switch shuts off the ignition control and closes
the main gas valve. To reset, push the button on top of the
switch.
Auxiliary Limit
This control is located in the side of the
circulation air blower housing. The switch opens and shuts
off the blower/ignition control and closes the main gas valve
should the circulation blower fail to operate. This control
resets automatically.
High Altitude
The input rate shown on the rating plate is for elevations
up to 2000 feet. For elevations from 2001 to 4500 feet, the
input rate is reduced by 5%. For elevations above 4501 feet,
refer to the National Fuel Gas Code Z223.1 (latest edition)
or the Canadian Installation Codes CAN/CGA-B149.1 &
B149.2 for further details.
Secure Owner’s Approval
When the system is functioning properly, secure the owner’s
approval. Show the owner the location of all disconnect
switches and the thermostat. Instruct the owner on how to
start and stop the unit and how to adjust temperature settings
within the limitations of th
e system.
MAINTENANCE
Periodic inspection and maintenance normally consists of
changing or cleaning the
fi
lters and cleaning the outdoor coil.
On occasion, other components of the furnace may also require
cleaning.
2. When the speed of the combustion air blower reaches
proper RPM, the pressure switch closes, initiating a
pre-purge period (30 seconds nominal).
3. When the pre-purge period has expired, the ignition
control energizes the main gas valve and spark
electrode for a period of 10 seconds.
4. If
the
fl ame sensor does not sense that a fl ame has been
established in the 10-second interval, then the ignition
control will de-energize the gas valve, and begins a 30
second interpurge period, then initiates another trial for
ignition.
5. The ignition control is designed to repeat this “trial
for ignition” a total of three times. If, at the end of the
third trial, fl ame still has not been established, then the
ignition control will try to light again 1 hour later. The
1-hour retry is indefi nite. The ignition control can be
reset by interrupting the unit power or the thermostat
circuit.
6. When the thermostat is sa
Ɵ
s
fi
ed, the combus
Ɵ
on air blower
and gas valve are de-energized. The circulation air
blower will continue to run for a short period after the
furnace is shut down.
Blower OFF Delay – Heating
The circulating air blower “OFF” delay is 120 seconds after
shutting down the burners. This delay is not adjustable.
Safety Controls
The control circuit includes the following safety controls:
Limit Control
This control is located inside the heating
compartment and is designed to open at abnormally high
circulating air temperatures. It resets automatically. The
limit control operates when a high temperature condition,
caused by inadequate airfl ow, occurs. This closes the main
gas valve.
Pressure Switch
If the combustion air blower should fail,
the pressure switch prevents the spark electrode and gas
valve from being energized.
Flame Sensor
If the ignition control does not receive a
signal from the fl ame sensor indicating that the burners have
established fl ame, the gas valve closes after the 10-second
trial for ignition period.
Shut off all electrical power to the unit before conducting
any maintenance procedures. Failure to do so could
cause personal injury.
WARNING
