Williams 1403622 Owner's Manual page 13

Installation
FIGURE 13
Checking the Gas Piping
Test all piping for leaks. When checking gas piping to the
furnace with gas pressure at less than 1/2 PSI, shut off manual
gas valve to the furnace. If the gas piping is to be checked with
the pressure at or above 1/2 PSI, the furnace and manual
shutoff valve must be disconnected during testing. Apply a
soap solution (or a liquid detergent) to each joint. Bubbles
forming indicate a leak. Correct even the slightest leak at once.
WARNING: Danger of property damage, bodily
injury or death. Never use a match or open flame
to test for leaks. Never exceed specified
pressures for testing. Higher pressures may
damage the gas valve and cause over firing
which may result in combustion chamber failure.
Liquefied petroleum gas (L.P.G.) is heavier than
air and it will settle in any low area, including
open depressions and it will remain there unless
area is ventilated. Never attempt start-up of the
unit before thoroughly ventilating the area and
smelling near the floor for gas odor.
FIGURE 14
Gas Pipe Sizes
Natural Gas
Pipe Capacity – Btu/hr.
(includes Fittings)
Pipe Size
Length of
1/2"
Pipe – Ft
20 92,000
40 63,000
60 50,000
L. P Gas
Pipe Capacity – Btu/hr.
(includes Fittings)
Pipe Size
Length of
1/2"
Pipe – Ft
20 189,000
40 129,000
60 103,000
3/4" 1"
190,000 350,000
130,000 245,000
105,000 195,000
3/4" 1"
393,000 732,000
267,000 504,000
217,000 409,000