Service manual

PRODUCT DESIGN
14
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. Use two pipe wrenches when making connection to the
gas valve to keep it from turning.
6. Install a manual shut off valve. This shut off valve should
be conveniently located within six (6) feet of the unit,
and between the meter and unit.
7. Tighten all joints securely.
8. The furnace shall be connected to the building piping
by one of the following:
a. Rigid metallic pipe and fittings.
b. Semirigid metallic tubing and metallic fittings. Alu-
minum alloy tubing shall not be used in exterior
locations.
c. Listed gas appliance connectors used in accor-
dance with the terms of their listing that are com-
pletely in the same room as the equipment.
d. In "b" and "c" above, the connector or tubing shall
be installed so as to be protected against physi-
cal and thermal damage. Aluminum-alloy tubing
and connectors shall be coated to protect against
external corrosion where they are in contact with
masonry, plaster, or insulation or are subject to
repeated wettings by such liquids as water (ex-
cept rain water), detergents, or sewage.
Figure 1
CHECKING THE GAS PIPING
CAUTION
TO AVOID THE POSSIBILITY OF PROPERTY DAMAGE,
PERSONAL INJURY OR FIRE, THE FOLLOWING IN-
STRUCTIONS MUST BE PERFORMED REGARDING
GAS CONNECTIONS AND PRESSURE TESTING.
The unit and its gas connections must be leak tested be-
fore placing in operation. Because of the danger of explo-
sion or fire, never use a match or open flame to test for
leaks. Never exceed specified pressure for testing. Higher
pressure may damage the gas valve and cause overfiring
which may result in heat exchanger failure.
This unit and its individual shutoff valve must be discon-
nected from the gas supply piping system during any pres-
sure testing of that system at test pressures in excess of 1/
2 psig (3.48 kPa).
This unit must be isolated from the gas supply system by
closing its individual manual shutoff valve during any pres-
sure testing of the gas supply piping system at test pres-
sures equal to or less than 1/2 psig (3.48 kPa).
TANKS AND PIPING - PROPANE UNITS
WARNING
PERSONAL INJURY HAZARD
IRON OXIDE (RUST) CAN REDUCE THE LEVEL OF
ODORANT IN PROPANE GAS. A GAS DETECTING DE-
VICE IS THE ONLY RELIABLE METHOD TO DETECT A
PROPANE GAS LEAK. CONTACT YOUR LOCAL PRO-
PANE SUPPLIER ABOUT INSTALLING A GAS DETECT-
ING WARNING DEVICE TO ALERT YOU IN THE EVENT
THAT A GAS LEAK SHOULD DEVELOP.
FAILURE TO DETECT A PROPANE GAS LEAK COULD
RESULT IN AN EXPLOSION OR FIRE WHICH COULD
CAUSE SERIOUS PERSONAL INJURY OR DEATH.
All propane gas equipment must conform to the safety stan-
dards of the National Board of Fire Underwriters (See NBFU
Manual 58) or Natural Standards of Canada B149.2, In-
stallation Code for Propane Gas Burning Appliances and
Equipment.
For satisfactory operation, propane gas pressure must be
10 inch W.C. at the furnace manifold with all gas appliances
in operation. Maintaining proper gas pressure depends on
three main factors.
1. Vaporization rate, which depends on (a) temperature of
the liquid, and (b) "wetted surface" area of the container
or containers.
2. Proper pressure regulation. (Two-stage regulation is
recommended from the standpoint of both cost and ef-
ficiency.)
3. Pressure drop in lines between regulators, and between
second stage regulator and the appliance. Pipe size
required 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
available from most regulator manufacturers and propane
gas suppliers.