Gas Supply And Piping - Williams 1753012 Owner's Manual

Installation
FIGURE 24

Gas Supply and Piping

The gas control valve is shipped with a sealed cover over the
gas inlet tapping. Do not remove seal until you are ready to
connect piping.
WARNING: Danger of property damage, bodily
injury or death. Make sure the furnace is
equipped to operate on the type of gas available.
Models designated as natural gas are to be used
with natural gas only. Furnaces designated for
use with liquefied petroleum gas (L.P.G.) have
orifices sized for commercially pure propane gas.
They cannot be used with butane or a mixture of
butane and propane.
Gas Supply
Minimum gas supply pressure for natural gas to the furnace
control valve is 5 inches water column and must not be more
than 7 inches water column.
Minimum gas supply pressure for L.P. gas to the furnace
control valve must be at least 11 inches water column and
must not exceed 13 inches water column.
Gas pressures and pressures to the burners must not exceed
the rated input and pressure shown on the rating plate. For
natural gas, the manifold pressure should be 3.2 inches water
column. The manifold pressure should be 10 inches water
column for L.P. gas. An orifice change may be required to suit
the gas supplied.
14
FIGURE 25
Orifice Sizes
The efficiency rating of these appliances is a product thermal
efficiency rating determined under continuous operating
conditions and determined independently of any installed
system.
The correct orifice sizes for the different input ratings when
using natural or L.P. gas are:
CAPACITY AND ORIFICE SIZING
INPUT
MODEL GAS
RATING
NUMBER TYPE
Btu/hr.
17035 Series 17,500
Nat.
17,500
17035 Series L.P.
Btu/hr. = British Thermal Units per hour.
Gas Piping
The gas supply line must be of an adequate size to handle the
Btu/hr. requirements and length of the run for the unit being
installed.
Determine the minimum pipe size from Figure 16, basing the
length of the run from the gas meter or source to the unit.
Main Burner Orifice
HEATING
CAPACITY
RATING
DRILL DEC
Btu/hr.
16,400 #47
.0780
16,400 N/A
.0500
QTY
1
1