268882-UIM-A-0407
Unitary Products Group
13
COMBUSTION AIR AND VENT PIPING ASSEMBLY
The final assembly procedure for the combustion air and vent piping is
as follows:
1.
Cut piping to the proper length beginning at the furnace.
2.
Deburr the piping inside and outside.
3.
Chamfer (bevel) the outer edges of the piping.
4.
Dry-fit the vent piping assembly from the furnace to the outside
termination checking for proper fit support and slope.
5.
Dry-fit the combustion air piping assembly checking for proper fit,
support and slope on the following systems:
A.
Sealed combustion air systems from the furnace to the out-
side termination.
B.
Ventilated combustion air systems from the furnace to the
attic or crawl space termination.
6.
Disassemble the combustion air and vent piping, apply cement
primer and the cement per the manufactures instructions. Primer
and cement must conform to ASTM D2564 for PVC, or ASTM
D2235 for ABS piping.
7.
All joints must provide a permanent airtight and watertight seal.
NOTE:
Be sure to visually check each pipe connection to make sure
the entire connection has primer on it. After applying the cement be
sure to twist the pipe into the fitting to be sure you have a tight seal.
8.
Support the combustion air and vent piping such that it is angled a
minimum of 1/4” per foot (0.635 cm/m) so that condensate will flow
back towards the furnace. Piping should be supported with pipe
hangers to prevent sagging.
9.
Seal around the openings where the combustion air and / or vent
piping pass through the roof or sidewalls.
COMBUSTION AIR / VENT CLEARANCES
IMPORTANT:
The vent must be installed with the following minimum
clearances, and must comply with local codes and requirements.
Solvent cements are flammable and must be used in well-ventilated
areas only. Keep them away from heat, sparks and open flames.
Do not breathe vapors and avoid contact with skin and eyes.
