Whirlpool WGFD28 Installation Instructions Manual Download Page 17

Page: 17 / 40

NOTE: Adjusting the minimum supply pressure below the limits in
the above table could lead to unreliable ignition. Gas input to the
burners must not exceed the rated input shown on the rating
plate. Overfiring of the furnace can result in premature heat
exchanger failure. Gas pressures in excess of 13" W.C. can also
cause permanent damage to the gas control valve.

At all altitudes, the manifold pressure must be within 0.3" W.C. of
that listed in the Specification Sheet applicable to your model for
the fuel used. At all altitudes and with either fuel, the air
temperature rise must be within the range listed on the furnace
nameplate.

Should this appliance be converted to LP gas, refer to the
instructions included in the factory-authorized LP gas conversion
kit.

High Altitude Derate

NOTE: The furnace will naturally derate itself with altitude. Do not
attempt to increase the firing rate by changing orifices or
increasing the manifold pressure. This can cause poor
combustion and equipment failure.

High altitude installations may require both a pressure switch and
an orifice change. These changes are necessary to compensate
for the natural reduction in the density of both the gas fuel and
the combustion air at higher altitude.

For installations above 7,000 ft (2,133.6 m), please refer to your
distributor for the required kit(s).

NOTE: In Canada, gas furnaces are only certified to 4,500 ft (1,371.6 m)

Contact the distributor for a tabular listing of appropriate manufacturer’s kits for propane gas and/or high altitude installations. The
indicated kits must be used to insure safe and proper furnace operation. All conversions must be performed by a qualified installer or
service agency.

Propane Gas Conversion

This furnace is configured for Natural gas. The appropriate
manufacturer’s propane gas conversion kit must be applied for
propane gas installations. Refer to “Propane Gas and/or High
Altitude Installations” section for details.

Contact your distributor for a tabular listing of appropriate
manufacturer’s kits for propane gas and/or high altitude
installations. The indicated kits must be used to ensure safe and
proper furnace operation. All conversions must be performed by
a qualified installer or service agency.

Gas Piping Connections

When sizing a trunk line, be sure to include all appliances which
will operate simultaneously.

The gas piping supplying the furnace must be properly sized
based on the gas flow required, specific gravity of the gas and
the length of the run. The gas line installation must comply with

local codes, or in their absence, with the latest edition of the
National Fuel Gas Code, NFPA 54/ANSI Z223.1.

Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; based
on 0.60 specific gravity gas

To connect the furnace to the building’s gas piping, the installer
must supply a ground joint union, drip leg, manual shutoff valve
and line and fittings to connect to the gas control valve. In some
cases, the installer may also need to supply a transition piece
from

¹⁄₂

" (1.3 cm) pipe to a larger pipe size.

The following stipulations apply when connecting gas piping.

■

Use black iron or steel pipe and fittings for building piping.

■

Use pipe joint compound (pipe dope) on male threads only.

Manifold Pressure

Pressure

Gas

Altitude

Kit

Orifice

High Stage

Low Stage

Switch Change

Natural

0 to 7,000 ft
(2,133.6 m)

None

#43

3.5" W.C.

1.9" W.C.

None

Propane

LPM-05

#55

10.0" W.C.

6.0" W.C.

None

Placeholder

Possible property damage, personal injury or death may
occur if the correct conversion kits are not installed. The
appropriate kits must be applied to ensure safe and proper
furnace operation. All conversions must be performed by
a qualified installer or service agency.

WARNING

Placeholder

To avoid possible unsatisfactory operation or equipment
damage due to underfiring of equipment, use the proper
size of Natural/propane gas piping needed when running
pipe from the meter/tank to the furnace.

CAUTION

Natural Gas Capacity of Pipe—Cu ft of Gas Per Hour (CFH)

Length of
Pipe—
ft (m)

Nominal Black Pipe Size

¹⁄₂

³⁄₄

¹⁄₄

¹⁄₂

10 (3)

132

278

520