9
3.1.5
– Venting Materials
When selecting vent material take into consideration that
appliances installed near a corrosive or potentially corrosive air
supply must be isolated from it or they will suffer damage to the
appliance and the venting system. The VTech may be vented
with the following manufactured products:
Manufactured prefabricated UL/ULC listed vents of AL29-4C,
single or double wall.
316L stainless steel in applications free of contaminants like
refrigerants, chlorine, etc.
In Canada
, the following plastic vent materials can be used,
if permitted by local jurisdictions:
o
UL/ULC S636 approved schedule 40 PVC
o
UL/ULC S636 approved schedule 80 PVC
o
UL/ULC S636 approved schedule 40 CPVC
o
UL/ULC S636 approved schedule 80 CPVC
o
UL/ULC S636 approved polypropylene (PPE)
In the US
, the following plastic vent materials can be used, if
permitted by local jurisdictions:
o
ANSI/ASTM D2665 approved PVC-DWV
o
ANSI/ASTM D1785 approved PVC Schedule 40
o
ANSI/ASTM F441 approved CPVC Schedule 40
o
UL/ULC S636 approved schedule 40 PVC
o
UL/ULC S636 approved schedule 80 PVC
o
UL/ULC S636 approved schedule 40 CPVC
o
UL/ULC S636 approved schedule 80 CPVC
o
UL/ULC S636 approved polypropylene (PPE)
WARNING
Use of cellular core PVC (ASTM F891), cellular core CPVC or
Radel (polyphenosulfone) inventing systems is prohibited
Covering non-metallic vent pipe and fittings with thermal
insulation is prohibited
Stainless steel venting can be ordered as single or double wall,
depending on the installation. Double wall is recommended on
Category II installations to ensure flue gas stay buoyant enough
to maintain draft. Double wall is also recommended anywhere
the vent may be contacted by personnel operating in the
mechanical room.
Vent Material
Maximum Flue
Temperature, °F
PVC
149
CPVC
194
Polypropylene (PPE)
230
316L Stainless
+300*
AL29-4C Stainless
+300*
*Stack is limited only by the allowable temperature rating of the
gas tight seals.
Always follow local codes when venting this appliance into a
masonry chimney. A standard masonry chimney must NOT be
used to vent the products of combustion from a positive pressure
appliance, or any condensing appliances, whether positive or
negative pressure (Category II, III or IV). As the VTech is a high
efficiency appliance, if a masonry chimney is to be used, it must
be used as a raceway for installation of a sealed, corrosion
resistant liner system. Chimney liner systems are typically made
from a high grade of corrosion resistant stainless steel such as
AL29-4C or equivalent. The corrosion resistant liner must be
properly sized and fully sealed throughout the entire length. Both
the top and the bottom of the masonry chimney must be capped
and sealed to provide a dead air space around the liner contained
within. Single wall venting is typically acceptable for the liner, but
any portion of the vent located outside of the masonry chimney
raceway should be double wall design.
Consult with local code officials to determine code
requirements or the advisability of using a masonry chimney
with a sealed corrosion resistant liner system.
3.2
– General Combustion Air Guidelines
Provisions for combustion and ventilation air are to be in
accordance with the section “Air for Combustion and Ventilation”
of the National Fuel Gas Code, ANSI Z223.1/NFPA 54, or clause
8.2, 8.3, and
8.4 of “Natural Gas and Propane Installation Code”,
CSA B149.1-15 and CSA B149.2-15
, or applicable provisions of
the local building codes. C
ombustion air can be supplied by
means of conventional venting, where combustion air is drawn
from the area immediately surrounding the appliance
(mechanical room must be positive pressure) which will require
openings in the mechanical room for fresh make-up air supply,
or with direct vent (direct vent combustion) where air is drawn
directly from the outside into the water heater jacket or blower.
Refer to the NFGC, Section 8.3 for additional information.
3.2.1
– Direct Combustion Air Supply
Direct Vent/Sealed Combustion
–
The combustion air can
be connected directly the blower. No filter is included; one
would only be needed if the intake termination may
occasionally ingest debris. Such a filter (supplied by others)
should be installed in an easily serviceable location.
VTech with Sealed Combustion