7
WARNING
1. All field gas piping must be pressure/leak tested prior to
operation. Never use an open flame. Use a soap solution or
equivalent for testing.
2. Gas pressure to appliance controls must never exceed 14"
W.C. (1/2 psi).
3. To reduce the opportunity for condensation, the minimum
sea level input to the appliance, as indicated on the serial
plate, must not be less than 5% below the rated input, or 5%
below the minimum rated input of duel rated units.
Figure 7.3
Recommended Sediment Trap/Manual Shut-off
Valve Installation — Side or Bottom Gas Connection
GAS
SUPPLY LINE
GAS
SUPPLY LINE
GROUND
JOINT
UNION
W/ BRASS
SEAT
MANUAL GAS
SHUT-OFF VALVE
3"
MIN.
SEDIMENT
TRAP
PLUGGED
1/8" NPT TEST
GAGE CONNECTION
TO
CONTROLS
➀
INSTALLATION
1. Installation of piping must conform with local building
codes, or in the absence of local codes, with the National
Fuel Gas Code, ANSI Z223.1 (NFPA 54) - Latest Edition. In
Canada, installation must be in accordance with CAN/CGA-
B149.1 for natural gas units and CAN/CGA-B149.2 for
propane units.
2. Piping to units should conform with local and national
requirements for type and volume of gas handled, and
pressure drop allowed in the line. Refer to Table 13.1 to
determine the cubic feet per hour (cfh) for the type of gas
and size of unit to be installed. Using this cfh value and
the length of pipe necessary, determine the pipe diameter
from Table 8.1. Where several units are served by the
same main, the total capacity, cfh and length of main must
be considered. Avoid pipe sizes smaller than 1/2". Table
8.1 allows for a 0.3" W.C. pressure drop in the supply
pressure from the building main to the unit. The inlet
pressure to the unit must be 6-7" W.C. for natural gas and
11-14" W.C. for propane gas. When sizing the inlet gas
pipe diameter, make sure that the unit supply pressure
can be met after the 0.3" W.C. has been subtracted. If the
0.3" W.C. pressure drop is too high, refer to the Gas
Engineer’s Handbook for other gas pipe capacities.
3. Install a ground joint union with brass seat and a manual
shut-off valve adjacent to the unit for emergency shut-off
and easy servicing of controls, including a 1/8" NPT
plugged tapping accessible for test gauge connection
(See Figure 7.3).
4. Provide a sediment trap before each unit and in the line
where low spots cannot be avoided. (See Figure 7.3).
5. When Pressure/Leak testing, pressures above 14" W.C.
(1/2 psi), close the field installed shut-off valve, disconnect
the appliance and its combination gas control from the
gas supply line, and plug the supply line before testing.
When testing pressures 14" W.C. (1/2 psi) or below, close
the manual shut-off valve on the appliance before testing.
➀ Manual shut-off valve is in the “OFF” position when handle is perpendicular
to pipe.
CAUTION
Purging of air from gas supply line should be performed as
described in ANSI Z223.1 - latest edition “National Fuel Gas
Code”, or in Canada in CAN/CGA-B149 codes.
METAL
SLEEVE
FIBER GLASS
INSULATION
MIN. 2"
2" MIN.
VENT TERMINATION
SUPPORT BRACKET
(where required)
(Make from 1" x 1" steel angle)
9"
9"
45
1"
METAL
SLEEVE
2" MIN.
VENT PIPE
DIAMETER
METAL FACE
PLATE
1"
12" min
TEE WITH DRIP LEG
AND CLEANOUT CAP
AT LOW POINT OF
VENT SYSTEM
POWER EXHAUSTER
PITCH VENT PIPE DOWNWARD
FROM UNIT 1/4" PER FOOT
12"
Min.
BREIDERT TYPE L
OR GARY STEEL
MODEL 1092 TERMINAL
Figure 7.1
Vent Construction Through Combustible Walls
Figure 7.2
Horizontal Venting - Breidert or Gary Steel Vent Terminal
Gas Connections
IMPORTANT
To prevent premature heat exchanger failure, the input to
the appliance, as indicated on the serial plate, must not
exceed the rated input by more than 5%.
