5
Refer to Figure 2 for the general layout at the unit. The
following rules apply:
1. Use black iron or steel pipe and fittings for the building
piping.
2. Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the fuel
used.
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 in a convenient location
(within six feet of unit) between the meter and the unit.
7. Tighten all joints securely.
8. The unit must be connected to the building piping by one
of the following methods:
• Rigid metallic pipe and fittings
• Semirigid metallic tubing and metallic fittings (Alumi-
num alloy tubing must not be used in exterior loca-
tions)
• Listed gas appliance connectors used in accordance
with the terms of their listing that are completely in the
same room as the equipment
• In the prior two methods above the connector or
tubing must be protected from physical and thermal
damage. Aluminum alloy tubing and connectors must
be coated to protect against external corrosion when
in contact with masonry, plaster or insulation or are
subject to repeated wettings by liquids (water - not rain
water, detergents or sewage)
Manual
Shut-Off
Valve
Gas
Valve
Drip Leg
Ground Joint Union
(Installed Ahead Of Gas Valve)
Reduce coupling 1/2" x 1/8",
with 1/8" pipe plug to measure
line gas pressure.
Figure 2
Proper Piping Practice
CHECKING THE GAS PIPING
CAUTION
To prevent personal injury or property
damage due to fire, the following
instructions must be performed regarding
gas connections and pressure testing:
• The unit and its gas connections must be
leak tested before placing in operation.
Because of the danger of explosion or
fire, never use a match or open flame to
test for leaks. Never exceed specified pres-
sures for testing. Higher pressure may
damage gas valve and cause overfiring
which may result in premature heat ex-
change failure.
• This unit and its shut-off valve must be
disconnected from the gas supply during
any pressure 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 manual shut-
off valve during any pressure testing of
the gas supply piping system at test pres-
sures equal to or less than 1/2 PSIG
(3.48kPa).
WARNING
To avoid personal injury or property
damage, be sure there is no open flame in
the vicinity during air bleeding procedure.
There will be air in the gas supply line after testing for leaks
on a new installation. Therefore, the air must be bled from
the line by loosening the ground joint union until pure gas is
expelled. Tighten union and wait for five minutes until all gas
has been dissipated in the air. Be certain there is no open
flame in the vicinity during air bleeding procedure. The unit
is placed in operation by closing the main electrical discon-
nect switch for the unit.