506271-01 Page 11 of 14Issue 0921
10-second interval, then the ignition control will de-
energize the gas valve.
6. The ignition control is designed to repeat this “trial for
ignition” a total of three times. If, at the end of the third
trial, flame still has not been established, then the ignition
control will try to light again 1 hour later. The 1-hour
retry is indefinite. The ignition control can be reset by
interrupting the unit power or the thermostat circuit.
7. When the thermostat is satisfied, the draft motor and
gas valve are de-energized. The blower motor will
continue to run for a short period after the furnace is
shut down.
Blower Delay – Heating
The on/off delay of the circulating air blower is controlled by
a timing circuit in the integrated ignition control. Timings are
not adjustable. The blower “ON” delay is 30 seconds after
the burners are lit and the blower “OFF” timing is 120
seconds after shutting down the burners.
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 airflow, occurs. This closes the main gas valve,
and the circulation air blower continues to operate in this
situation.
Pressure Switch If the draft motor 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 flame sensor indicating that the burners have
established flame, the main gas valve closes after the 10-
second trial for ignition period.
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 4500 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 the system.
Periodic inspection and maintenance normally consists of
changing or cleaning the filters and cleaning the outdoor
coil. On occasion, other components of the furnace may
also require cleaning.
MAINTENANCE
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.
Outdoor Coil
Dirt and debris should not be allowed to accumulate on the
outdoor coil surface or other parts in the air circuit. Cleaning
should be as often as necessary to keep coil clean. Use a
brush, vacuum cleaner attachment, or other suitable means.
If water is used to clean the coil, be sure the power to unit is
shut off prior to cleaning. Care should be used when
cleaning the coil so that the coil fins are not damaged.
Do not permit the hot condenser air discharge to be
obstructed by overhanging structures or shrubs.
Shut off all electrical power to the unit before conducting
any maintenance procedures. Failure to do so could
cause personal injury.
WARNING