Form RZ-NA-I-FT, Mfg No. 173473 Rev 8, Page 9
Roof or Building Overhang
3 (1M) minimum
12
(305mm)
minimum
6 (2M)
minimum
Wall
Parapet or
Adjoining Building
Approved clearance
thimble for single-wall
vent pipe is required
when flue pipe extends
through combustible
materials.
Note position of vent
cap openings.
Pitch flue pipe down toward outlet
1/4 per foot for condensate drainage.
(NOTE: Applies to entire horizontal
vent run.)
Adjoining Building
Parapet or
Roof or Building Overhang
6 (2M)
minimum
3 (1M) minimum
12
(305mm)
minimum
Wall
Approved clearance
thimble is required
when flue pipe extends
through combustible
materials. Follow
the requirements
of the double-wall
pipe manufacturer.
Pitch flue pipe down toward
outlet 1/4 per foot for con-
densate drainage.
(NOTE: Applies to entire
horizontal vent run.)
Note position of
vent cap openings.
6 (152mm) minimum
Follow instructions on page 8 to join single
and double-wall pipe and to seal the connection.
Figure 7B - Horizontal Vent Terminals
Horizontal Vent Terminal
Clearances
A vent cap is required. Maintain a clearance
of 12" (305mm) from the wall to the vent
terminal cap for stability under wind condi-
tions.
Products of combustion can cause discolora-
tion of some building finishes and deteriora-
tion of masonry materials. Applying a clear
silicone sealant that is normally used to pro-
tect concrete driveways can protect masonry
materials. If discoloration is an esthetic prob-
lem, relocate the vent or install a vertical vent.
Structure
Minimum Clearances for Vent Termination
Location (all directions unless specified)
Forced air inlet within 10 ft (3.1m)
3 ft (0.9m) above
Combustion air inlet of another appliance
6 ft (1.8m)
Door, window, or gravity air inlet
4 ft (1.2m) horizontally
(any building opening)
4 ft (1.2m) below
1 ft (30cm) above
Electric meter, gas meter * and relief
4 ft (1.2m) horizontally
equipment
Gas regulator *
3 ft (0.9m)
Adjoining building or parapet
6 ft (1.8m)
Adjacent public walkways
7 ft (2.1m) above
Grade (ground level)
7 ft (2.1m) above
*Do not terminate the vent directly above a gas meter or service regulator.
Single-Wall Vent Run
and Single-Wall
Terminal End
Single-Wall Vent Run and Double-Wall Terminal End
12. Gas Piping and Pressures
WARNING: This appliance is equipped for a
maximum gas supply pressure of 1/2 pound, 8
ounces, or 14 inches water column. Supply
pressure higher than 1/2 pound requires
installation of an additional lockup-type service
regulator external to the unit.
PRESSURE TESTING SUPPLY PIPING
Test Pressures Above 1/2 PSI:
Disconnect the heater and manual
valve from the gas supply line which is to be tested. Cap or plug the
supply line.
Test Pressures Below 1/2 PSI:
Before testing, close the manual valve
on the heater.
All piping must be in accordance with requirements outlined in the
National Fuel Gas Code ANSI/Z223.1a (latest edition) or CAN/CGA-
B149.1 and B149.2 (See Paragraph 1). Gas supply piping installation
should conform with good practice and with local codes. Support gas
piping with pipe hangers, metal strapping, or other suitable material;
do no rely on the heater to support the gas pipe.
Unit heaters are orificed for operation with natural gas having a heat-
ing value of 1000 (± 50) BTUH per cubic ft or propane gas with a
heating value of 2550 BTUH per cubic ft. If the gas at the installation
does not meet these specifications, consult the factory for proper ori-
ficing.
Pipe joint compounds (pipe dope) shall be resistant to the action of
liquefied petroleum gas or any other chemical constituents of the
gas being supplied.
Install a ground joint union and manual shut-off valve upstream of the
unit control system, as shown in Figure 8. The 1/8" plugged tapping in
the shutoff valve provides connection for a supply line pressure test
gauge. The National Fuel Gas Code requires the installation of a trap
with a minimum 3" drip leg. Local codes may require a minimum drip
leg longer than 3" (typically 6").
Gas connection is 1/2" for Sizes 30-200 and 3/4" for Sizes 250-300.
Leak-test all connections by brushing on a leak-detecting solution.
WARNING: All components of a gas supply system
must be leak tested prior to placing equipment in
service. NEVER TEST FOR LEAKS WITH AN
OPEN FLAME. Failure to comply could result in
personal injury, property damage or death.