Down Discharge Applications
Cut insulation around bottom openings and remove panels from
the bottom of the unit, saving the screws holding the panels in
place.
DUCTWORK
Duct systems and register sizes must be properly designed for
the C.F.M. and external static pressure rating of the unit.
Ductwork should be designed in accordance with the
recommended methods of Air Conditioning Contractors of
America Manual D (Residential) or Manual Q (Commercial).
All ductwork exposed to the outdoors must include a
weatherproof barrier and adequate insulation.
Aduct system should be installed in accordance with Standards
of the National Board of Fire Underwriters for the Installation of
Air Conditioning, Warm Air Heating and Ventilating Systems.
Pamphlets No. 90A and 90B.
The supply duct from the unit through a wall may be installed
without clearance. However, minimum unit clearances as shown
in the appendix must be maintained. The supply duct should
be provided with an access panel large enough to inspect the
air chamber downstream of the heat exchanger. A cover should
be tightly attached to prevent air leaks,
For duct flange dimensions on the unit refer to the Unit
Dimension illustration in the appendix.
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
To PREVENT PROPERTY DAMAGE DUE TO FIRE AND LOSS OF
EQUIPMENT EFFICIENCY OR EQUIPMENT DAMAGE DUE TO DUST AND LINT
BUILD UP ON INTERNAL PARTS, NEVER OPERATE UNIT WITHOUT AN AIR
FILTER INSTALLED IN THE RETURN AIR SYSTEM.
Even though a return air filter is not supplied with this unit,
there must be a means of filtering all return air. The *PG1248
and *PG1260 models are provided with internal filter racks for
down-discharge applications. 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: When installing a filter, the air flow arrows on the
filter must point toward the circulator blower.
VENTING
NOTE: Venting is self-contained. Do not modify or block.
F L U E H O O D INSTALLATION
Install the flue hood and bug screen prior to operation of the
unit.
To install the flue hood cover and bug screen:
1. Remove the flue hood and bug screen from inside the heat
exchanger compartment.
2. Slide the bug screen over the flanges of the flue hood and
attach the flue hood and screen to the unit with the sheet
metal screws provided.
Flue Hood and Bug Screen Installation
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
A POSITIVE LIQUID
SEAL IS REQUIRED
Drain Connection
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. Thermostat calls for heat. The induced draft blower
energizes for a 15-second pre-purge.
2. The spark igniter and gas valve energizes for 7 seconds.
NOTE: The igniter produces a very intense electrical spark
that ignites the gas.
3. The 30-second HEAT FAN ON delay time begins.
4. The unit delivers heat to the conditioned space until the
thermostat is satisfied.
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