Service Manual

PRODUCT DESIGN
28
GAS VALVE
This unit is equipped with a 24 volt gas valve controlled dur-
ing furnace operation by the integrated control module. As
shipped, the valve is configured for natural gas. The valve is
field convertible for use with propane gas by using the ap-
propriate propane gas conversion kit. Taps for measuring
the gas supply pressure and manifold pressure are provided
on the valve.
NOTE: The gas supply pressure on White-Rodgers "G"
model gas valve, used on single stage furnaces, can
be checked with a gas pressure test kit (Part
#0151K00000S) available through our authorized dis-
tributors.
The gas valve has a manual ON/OFF control located on the
valve itself. This control may be set only to the “ON” or “OFF”
position. Refer to the Lighting Instructions Label or the “Put-
ting the Furnace Into Operation” section of this manual or
the installation instructions for use of this control during start
up and shut down periods.
GAS PIPING CONNECTIONS
CAUTION
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.
The gas piping supplying the furnace must be properly sized
based on the gas flow required, specific gravity of the gas,
and 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.
Length of Nominal Black Pipe Size
Pipe in Feet 1/2" 3/4" 1" 1 1/4" 1 1/2"
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 980
40 63 130 245 500 760
50 56 115 215 440 670
60 50 105 195 400 610
70 46 96 180 370 560
80 43 90 170 350 530
90 40 84 160 320 490
100 38 79 150 305 460
CFH =
(Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; Based on 0.60 Specific
Gravity Gas)
Natural Gas Capacity of Pipe
In Cubic Feet of Gas Per Hour (CFH)
BTUH Furnace Input
Heating Value of Gas (BTU/Cubic Foot)
To connect the furnace to the building’s gas piping, the in-
staller must supply a ground joint union, drip leg, manual
shutoff valve, and line and fittings to connect to gas valve. In
some cases, the installer may also need to supply a transi-
tion piece from 1/2" pipe to a larger pipe size.
The following stipulations apply when connecting gas pip-
ing. Refer to the following figures for typical gas line connec-
tions to the furnace.
1. Use black iron or steel pipe and fittings for the build-
ing piping.
2. Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
3. Use ground joint unions.
4. Install a drip leg to trap dirt and moisture before it can
enter the gas valve. The drip leg must be a minimum
of three inches long.
5. Install a 1/8" NPT pipe plug fitting, accessible for test
gage connection, immediately upstream of the gas
supply connection to the furnace.
6. Use two pipe wrenches when making connection to
the gas valve to keep it from turning. The orientation of
the gas valve on the manifold must be maintained as
shipped from the factory.
7. Install a manual shutoff valve between the gas meter
and unit within six feet of the unit. If a union is in-
stalled, the union must be downstream of the manual
shutoff valve, between the shutoff valve and the fur-
nace.
8. Tighten all joints securely.
9. Connect the furnace to the building piping by one of
the following methods:
– Rigid metallic pipe and fittings.
– Semi-rigid metallic tubing and metallic fittings. Alu-
minum alloy tubing must not be used in exterior loca-
tions. In order to seal the grommet cabinet penetra-
tion, rigid pipe must be used to reach the outside
of the cabinet. A semi-rigid connector to
the gas piping may be used from there.
10. Use listed gas appliance connectors in accordance with
their instructions. Connectors must be fully in the same
room as the furnace.
11. Protect connectors and semi-rigid tubing against physi-
cal and thermal damage when installed. Ensure alumi-
num-alloy tubing and connectors are coated to protect
against external corrosion when in contact with masonry,
plaster, or insulation, or subjected to repeated wetting
by liquids such as water (except rain water), detergents,
or sewage.
CAUTION
E
DGES OF SHEET METAL HOLES MAY BE SHARP.
U
SE GLOVES A PRECAUTION
WHEN REMOVING HOLE PLUGS.