Gas Conversions; Gas Supply - Williams 1773512 Owner's Manual

INSTALLING YOUR FURNACE

Gas Conversions

Converting to another gas type must be performed
by a qualified service technician. If the type of the gas
supplied to the dwelling is not the same type as your
furnace (natural or propane gas), it must be converted.
It will be necessary to do the following:
1. Change nozzle.
a. Remove the screw indicated to the right.
2. Remove the nozzle assembly from the burner
inserting the screwdriver as indicated by the arrow.
3. Remove the nozzle from the support and replace it
with the correct one. Reassemble the nozzle assembly
and the screw indicated at point 1. Set the burner
pressure as indicated in the table below:
GAS TYPE NOZZLE PART NUMBERS
NATURAL P332551
PROPANE P332552
MIN. INLET LINE
GAS TYPE
GAS PRESSURE
NATURAL 7.0 inches w.c.
PROPANE 11.0 inches w.c.
10
HIGH EFFICIENCY DIRECT VENT FURNACES
NOZZLE DIAMETER
0.09 in.
0.05 in.
MAX. MANIFOLD MIN. MANIFOLD
GAS PRESSURE GAS PRESSURE
3.2 inches w.c. 1.8 inches w.c.
10.6 inches w.c. 6.5 inches w.c.
4. Check the gas pressure and settings.
MINIMUM BURNER PRESSURE SETTING
a. Set LOW burner capacity by pressing button Z2
b. Connect a micro manometer to the test gauge B
Figure 8
Rotate the internal screw "D" Figure 8 and set the
c.
pressure at the correct value
MAXIMUM BURNER PRESSURE SETTING:
a. Set HI burner capacity by pressing button Z2
b. Connect a micro manometer to the test gauge B
Figure 8
c. Rotate the external screw "C" Figure 8 and set the
pressure at the correct value

Gas Supply

Check all local codes for requirements, especially for the size
and type of gas supply line required. On natural gas lines less
than 15" (380 mm) long, use 1/2" tube; on longer runs, use
3/4" iron tube or equal. On propane gas lines please consult
propane gas supplier.
INSTALLING A NEW MAIN GAS SHUTOFF VALVE
Each furnace should have its own manual gas shutoff valve.
A manual main gas shutoff valve should be located in the
vicinity of the furnace. Where none exists, or where its size
or location is not adequate, contact your local authorized
installer for installation or relocation.
Compounds used on threaded joints of gas piping must be
resistant to the action of propane gas. The gas lines must
be checked for leaks by the installer. This should be done
with a soap solution watching for bubbles on all exposed
connections, and if unexposed, a pressure test should be
made. Correct all gas leaks before operating the furnace.
Never use an exposed flame to check for leaks. The
furnace must be disconnected from piping at inlet of
control valve and pipe capped or plugged for a pressure
test. Never pressure test with furnace connected; the
control valve will sustain damage!
A gas shutoff valve and ground joint union should be
installed in the gas line upstream of the gas control valve to
aid in servicing. It is required by the National Fuel Gas Code
that a drip line be installed near the gas inlet. This should
consist of a vertical length of pipe tee connected into the gas
line that is capped on the bottom in which condensation
and foreign particles may collect.
Use of the following gas connectors is recommended:
– ANSI Z21.24 Appliance Connectors of Corrugated Metal
Tubing and Fittings. CGA 6.10.
– ANSI Z21.45 Assembled Flexible Appliance Connectors of
Other Than All–Metal Construction.
The above connectors may be used if accepted by the
authorities having jurisdiction.
PRESSURE TESTING OF THE GAS SUPPLY SYSTEM
1. To check the inlet pressure to the gas valve, a plugged
tapping, accessible for a test gauge connection, is
provided on the gas valve. Figure 8 - A