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Venting Through Closed Spaces
If the vent piping passes through a closed space, a minimum
clearance of 8” (20 cm) when installed horizontally, 6”
(15 cm)
when installed vertically should be maintained between the vent
pipe and combustibles and noncombustibles. Be sure to follow
local codes.
For maintenance and inspection purposes, the following access
panels are required.
● Two (2) inspection access panels large enough to allow
access for venting inspection. One (1) of these access
panels should be close to where the vent pipe enters the
ceiling. The other access panel should be near the vent
termination.
● A ventilation access panel with a 16 in
2
(103 cm
2
) opening
should be provided every 10 ft (3 m).
Inspection
Access Panel #1
Inspection
Access Panel#2
Ceiling
Board
Vent Pipe
Wall Thimble
1/4” per foot
downward slope
Vent Adapter
A UL 1738 approved stainless steel vent
adapter is required for vent connection.
Read the following instructions before
installation.
● Test fit the adapter over the water
heater collar before proceeding. Adjust
clamp as needed.
● With an alcohol wipe, clean inside
surface "A" of adapter and outside
surface of "B" of heater collar.
● Apply 1/4" (6 mm) wide bead of high
temperature silicone (500°F) (260°C)
around outside of heater collar "B".
● Slide adapter end "A" down over heater
collar "B" as far as it will go.
● Tighten the clamp around the collar.
● Inspect the inside of the adapter to
verify that the collar and adapter are
sealed. If more sealant is required,
apply sealant to a flat tool, then spread
around the collar edge on inside
of
adapter.
● Ensure that the clamp does not interfere
with the damper shaft.
NOTICE: Follow the vent adapter
manufacturer’s instructions
A
B
High Temp.
Sealant
Collar
Vent Adapter
RTG20002B
Clamp
Water Heater
Exhaust
Flow
Draining the Condensate
In order to prevent condensate from
draining back into the water heater, a
condensate trap and drain must be
installed in a horizontal vent section as
close as practical to the water heater vent
connection, uless the water heater is
vented horizontally with a 1/4” per foot
DOWNWARD slope towards the vent
terminal as shown below.
Condensate is known to be acidic; refer to
local, state (provincial) or federal codes
for proper handling and discharge
methods.
Ve nt
Adapter
3” (8 cm) Clearance
Support
Hanger
1/4” per foot downward slope
3’
(91 cm)
Max