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For down-discharge applications, the ductwork should be attached
to the roof curb prior to installing the unit. Ductwork dimensions
are shown in the roof curb installation manual.
If desired, supply and return duct connections to the unit may be
made with flexible connections to reduce possible unit operating
sound transmission.
Filters
Even though a return air filter is not supplied with this unit, there
must be a means of filtering all return air. All units may be
externally filtered.
Refer to the unit filter size chart in the appendix for filter size
information.
Filters installed external to the unit should be sized in accordance
with their manufacturer recommendations. A throwaway filter must
be sized for a maximum face velocity of 300 feet per minute.
Filter Installation
IMPORTANT NOTE: When installing a filter, the air flow arrows on
the filter must point toward the circulator blower.
NOTE: Venting is self-contained. Do not modify or block.
Installation - Flue Hood Exhaust
1.
Locate the flue hood assembly box in the unit.
2.
Slide screen over flanges on the lower flue hood.
3.
Slide screen and lower flue hood into hood.
4.
Using the three screws provided, attach the hood (with the
opening facing down) over the flue exhaust opening in the
utility panel.
HOOD
LOWER
FLUE
HOOD
LIP
Installation - Combustion Air Intake Hood
1.
Locate the second hood.
2.
Using the three screws provided, attach the hood (with the
opening facing down) to the heat exchanger access door.
Venting
SCREEN
Condensate Drain
Condensate Drain Connection
A 3/4" NPT drain connection is supplied for condensate piping. An
external trap must be installed for proper condensate drainage.
DRAIN
CONNECTION
UNIT
FLEXIBLE
TUBING-HOSE
OR PIPE
A POSITIVE LIQUID
SEAL IS REQUIRED
Normal Sequences Of Operation
Heating
This unit is equipped with an ignition control that automatically
lights the main burner. DO NOT attempt to light the main burners
by any other method.
1.
R and W thermostat contacts close, initiating a call for heat.
2.
Integrated control module performs safety circuit checks.
3.
Inducer draft blower is energized for 30 second pre-purge
period causing pressure sensor contacts to close.
4.
At the end of pre-purge period, integrated control module
transitions the induced draft blower to light-off setting.
5.
Once the light-off pressure setting is verified by the
integrated control module, the spark igniter and gas valve
are energized for 4 seconds.
NOTE: The igniter produces a very intense electrical spark that
ignites the gas.
6.
Integrated control module monitors flame presence. Gas
valve will remain open only if the flame is detected.
7.
The 5-second HEAT FAN ON delay time begins after main
burner lights.
12
2" MINIMUM
3" MINIMUM
Drain Connection
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