SECTION IV: INSTALLATION
VENT & COMBUSTION AIR INTAKE
DANGER
Failure to properly install the vent and combustion air intake system as outlined in this
manual can result in unsafe operation of the water heater. To avoid the risk of fire,
explosion, or asphyxiation from carbon monoxide, never operate this water heater
unless it is properly vented and has adequate air supply for combustion and dilution of
flue gas. Be sure to inspect the system for proper installation at initial start-up; and at
least annually thereafter. See the Maintenance section for more information.
The water heater venting and combustion air intake shall be installed in accordance with
these instructions and can be installed as a power direct vent system (combustion air
from outside the building, i.e. “two-pipe”) or power vent system (combustion air from
inside the building, i.e. “one-pipe”). If applicable, installation must also comply with the
venting system manufacturer’s instructions. Vertical or horizontal (side-wall) configura-
tions may be used with a one-pipe, two-pipe, or concentric vent termination.
Note: If air from inside the building will be used for combustion air, the require-
ments in Section III, “Unconfined Space” must be met.
The water heater is supplied with a rubber coupling (with clamps) that connects to the
blower assembly outlet. The air intake piping is preassembled to route dilution air to the
blower assembly and combustion air to the burner chamber. All vent length measure-
ments specified in this manual are in addition to the preassembled piping supplied with
the water heater. Equivalent pipe run lengths shall not be greater than the maximum
lengths (or less than minimums) given in Tables 4 and 5.
Note: DO NOT connect the water heater to an existing vent or chimney. It must
be vented separately from all other appliances.
The following materials are approved for use as the vent and combustion air intake
piping:
• PVC (DWV, ASTM-D2665 or CSA B181.2)
• PVC (Schedule 40, ASTM-D1785 or CSA B137.3)
• PVC (SDR Series, ASTM-D2241 or CSA B137.3)
• CPVC (Schedule 40, ASTM-F441 or CSA B137.3)
• CPVC (SDR Series, ASTM-F442)
• ABS (Schedule 40, DWV, ASTM-D2661 or CSA B181.1)
• AL29-4C Stainless Steel
• PVC IPEX 1738 (UL 1738, ASTM D2665)
In Canada, check local codes to ensure that SDR series is approved for use. SDR is
not approved for all installations in Canada.
The following materials are approved for use for the fittings in the vent and combustion
air intake systems:
• PVC (Schedule 40 DWV, ASTM D2665)
• CPVC (Schedule 40, ASTM F438)
• ABS (Schedule 40 DWV, ASTM D2661)
• AL29-4C Stainless Steel
• PVC IPEX 1738 (UL 1738, ASTM D2665)
The use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenylsulfone) in
non-metallic vent pipe and systems is prohibited. Covering non-metallic vent pipe and fittings
with thermal insulation is prohibited.
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