29
Table L: Venting Category Requirements
6. DO NOT terminate vent closer than 5 ft below roof
overhang.
7. The vent terminal requires a 12 in. vent terminal
clearance from the wall.
8. Terminate vent at least 1 ft above grade, including
normal snow line.
9. Multiple direct vent installations require a 4 ft
clearance between the ends of vent caps located
on the same horizontal plane.
Combustion
Air Supply
Exhaust
Configuration
Heater Venting
Category
Certified
Materials
Combustion Air
Inlet Material
Vertical
Venting
From Inside Building
(Non-Direct Venting) Horizontal Through-
the-Wall Venting
Vertical
Venting
From Outside Building
(Direct Venting)
Horizontal Through-
the-Wall Venting
IV
CAT IV
(AL29-4C)
PVC
CPVC
Polypropylene*
Galvanized Steel
PVC
ABS
CPVC
* Only Centrotherm polypropylene material is approved for use with the XTherm.
Canadian Installations
Refer to latest edition of the B149 Installation Code.
A vent shall not terminate:
1. Directly above a paved sidewalk or driveway
which is located between two single-family dwell-
ings and serves both dwellings.
2. Less than 7 ft (2.13 m) above a paved sidewalk or
paved driveway located on public property.
3. Within 6 ft (1.8 m) of a mechanical air supply inlet
to any building.
4. Above a meter/regulator assembly within 3 ft (915
mm) horizontally of the vertical centre-line of the
regulator.
5. Within 6 ft (1.8 m) of any gas service regulator
vent outlet.
6. Less than 1 ft (305 mm) above grade level.
7. Within 3 ft (915 mm) of a window or door which
can be opened in any building, any non-mechani-
cal air supply inlet to any building or the
combustion air inlet of any other appliance.
8. Underneath a verandah, porch or deck, unless the
verandah, porch or deck is fully open on a mini-
mum of two sides beneath the floor, and the
distance between the top of the vent termination
and the underside of the verandah, porch or deck
is greater than 1 ft (305 mm).
WARNING:
The Commonwealth of Massachusetts
requires that sidewall vented heaters, installed in
every dwelling, building or structure used in whole or
in part for residential purposes, be installed using
special provisions as outlined on page 54 of this
manual.