GM9S80 Service Manual
SYSTEM OPERATION
22
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.
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.
8. Tighten all joints securely.
9. Connect the furnace to the building piping by one of
the following methods:
-
locations. In order to seal the grommet cabinet
penetration, 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
physical and thermal damage when installed. Ensure
aluminum-alloy tubing and connectors are coated to
with masonry, plaster, or insulation, or subjected to
water), detergents, or sewage.
-
Before placing unit in operation, leak test the unit and gas
connections.
Check for leaks using an approved chloride-free soap and
water solution, an electronic combustible gas detector, or
other approved testing methods.
pressure may damage the gas valve and cause subsequent
-
fore pressure testing the supply piping system with pressures
-
test pressures equal to or less than 1/2 psig (3.48 kPa).
-
A gas detecting warning system is the only reliable way to
level of odorant in propane gas. Do not rely on your sense of
smell. Contact a local propane gas supplier about installing
a gas detecting warning system. If the presence of gas is
suspected, follow the instructions on this page.
All propane gas equipment must conform to the safety stan-
dards of the National Board of Fire Underwriters, NBFU
Manual 58.
For satisfactory operation, propane gas pressure must be
11 inch WC at the furnace manifold with all gas appli ances
in operation. Maintaining proper gas pressure depends on
three main factors:
1. Vaporization rate, depending on temperature of the
containers.
2. Proper pressure regulation. (Two-stage regulation is
3. Pressure drop in lines between regulators, and be-
tween second stage regulator and the appliance. Pipe
size will depend on length of pipe run and total load of
all appliances.
Complete information regarding tank sizing for vaporiza tion,
recommended regulator settings, and pipe sizing is avail-
able from most regulator manufacturers and propane gas
suppliers. Always use a pipe sealant approved for natural
gas and LP gas.
Refer to the following illustration for typical propane gas in-
stallations and piping.