Step 4—Metal Vent Installations
The furnace is approved for use with Type B vent that terminates
through the roof. Refer to the A.G.A./GAMA Venting Tables
supplied with furnace for proper sizing and setup of this furnace
with Type B vent for a dedicated vent system or a common vented
system.
Step 5—Masonry Chimney Installations
This furnace can be common vented into an existing tile lined
masonry chimney provided:
1. The chimney is currently serving at least 1 drafthood equipped
appliance.
2. The vent connectors and chimney are sized in accordance with
the A.G.A./GAMA Venting Tables supplied with furnace.
This furnace must not be vented ALONE into an existing masonry
chimney (either tile lined or unlined) unless the chimney is also
lined with either a Type B vent system or a listed single-wall metal
lining system (as specified in the A.G.A./GAMA Venting Tables).
Both of these systems must be sized in accordance with the
A.G.A./GAMA Venting Tables supplied with furnace.
Before venting this furnace into a chimney, check chimney for
deterioration and repair if necessary.
This furnace must not be vented into a chimney serving a separate
appliance designed to burn solid fuel.
Type B vent connector must be used on all installations. It must be
sized per the A.G.A./GAMA Venting Tables supplied with fur-
nace.
Step 6—Multistory Installations
For multistory installations, refer to Appendix G of the NFGC or
Canadian Standard CAN/CGA-B149. Additional vent connectors
should be sized per the enclosed instructions.
Step 7—Sidewall Venting Installations
GENERAL — This furnace is A.G.A. and C.G.A. designed certi-
fied for sidewall venting through an outside wall by use of the
following auxiliary draft inducer:
Field Controls Company Model No. DGF-2 sidewall venting
kit.
Follow Installation Instructions supplied with DGF-2 kit.
The minimum vent length is 5 ft and the maximum is 60 ft.
LOCATION REQUIREMENTS FOR SIDEWALL VENTING
Locate vent terminal adhering to the following minimum clear-
ances:
1. Vent terminal must be located at least 1 ft above the grade or
at least 1 ft above normal expected snowfall.
2. Avoid installing vent terminal above public walkways. If this
is not possible, install terminal at least 7 ft above walkway.
3. Vent terminal should be at least 4 ft to the side of and at least
1 ft above doors and windows.
4. Vent terminal should be at least 3 ft above any forced air inlet
located within 10 ft.
5. Vent terminal should be located at least 6 ft from the
combustion-air intake of another appliance.
6. Vent terminal should be located at least 4 ft above any electric
or gas meters, regulators, and relief equipment.
SEQUENCE OF OPERATION
Using the schematic diagram in Fig. 12, follow the sequence of
operation through the different modes. This furnace has a unique
control system. Read and follow the wiring diagram very carefully.
Step 1—Heating Mode
When wall thermostat calls for heat, the R-W circuit closes.
1. Inducer start-up sequence—Power from transformer energizes
fan control board. The fan control energizes the induced-draft
blower motor. Pressure switch P normally open contacts close
to energize ignition module.
2. Ignition module self-check—Upon being energized, the igni-
tion module performs a 2-sec self-check. The ignition module
checks for the presence of flame. If flame is present when it
should not be, the module energizes the blower. The gas pilot
valve remains closed, and ignitor is not energized. If no flame
is detected, the module initiates the ignition sequence.
3. Ignition sequence—The ignition module energizes the hot
surface pilot ignitor. The module then checks for a missing or
broken ignitor. If ignitor is faulty, there is no further system
response. If ignitor is functional, the pilot gas valve is
energized and gas is allowed to flow to pilot where it is
ignited. A flame sensing period then begins.
4. Flame sensing—Pilot flame is sensed through the ignition
module’s flame sensing rod. If pilot flame is not sensed, the
ignitor remains energized, and pilot gas valve remains open. If
this is due to a gas interruption, the system continues its
attempt to light pilot until gas is restored and unit lights or
system is turned off. When pilot flame is sensed, the main gas
valve opens and the pilot flame lights the burners. The blower
on delay period then begins.
5. Blower on delay—The fan control starts blower after 30 sec.
The blower on delay is not adjustable.
6. Blower off delay—When thermostat is satisfied, the circuit
between R and W is broken, de-energizing gas valve and
stopping gas flow to burners. The blower motor remains
energized 60, 90, 120, or 150 sec depending on blower off
delay selection (factory shipped set for 60-sec delay).
7. Post purge—Inducer motor remains energized for 5 sec after
burners are extinguished.
Step 2—Cooling Mode
When wall thermostat calls for cooling, the R-G and R-Y circuits
close. The R-Y circuit starts outdoor condensing unit, and the
combined R-Y and R-G circuits start furnace blower motor on
cooling speed.
When thermostat is satisfied, the R-G and R-Y circuits are broken.
The furnace blower de-energizes immediately.
START-UP, ADJUSTMENT, AND SAFETY CHECK
Step 1—General
1. The furnace must have a 115-v power supply properly
connected and grounded.
NOTE:
Proper polarity must be maintained for correct operation.
2. Thermostat wire connections at R, W, Y, and C must be made
at the 24-v terminal block on control board.
3. The gas service pressure must not exceed 0.5 psig (14-in. wc),
but must be no less than 0.16 psig (4.5-in. wc) for natural gas.
Step 2—Remove Shipping Bracket
The furnace is equipped with a metal blower wheel shipping
bracket which MUST be removed before putting furnace into
operation. To remove this bracket:
1. Remove blower access panel.
2. Remove 2 mounting screws.
3. Slide bracket off blower wheel hub.
4. Replace blower panel.
Step 3—Purge Gas Lines
If not previously done, purge the lines after all connections have
been made and check for leaks.
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