Multi-Concentric Vent Terminations - A.O. Smith BTX 100 Instruction Manual

5. Install rain cap and small diameter pipe assembly in Y concentric
fitting and large pipe assembly. Ensure small diameter pipe is
bottomed and cemented in Y concentric fitting.
6. Secure assembly to structure as shown in Figure 25 using field-
supplied metal strapping or equivalent support material.
note: ensure termination location clearance dimensions are
as shown in the diagrams found in figure 25 and 26. when
extending the length of the 4" pipe, the added length beyond
21-1/8" must be deducted from the maximum equivalent feet
of vent pipe.
note: If assembly needs to be extended to allow side wall
thickness requirement, the 2 pipes supplied in the kit may be
replaced by using same diameter, field-supplied SDR-26 PVC
(d2241) pipe. do not extend 21 1/8" (53.6 cm) dimension more
than 60" (1.5 m). see figure 21.
Do not use field-supplied couplings to extend pipes. Airflow
restriction will occur and the heater pressure switch may cause
intermittent operation.
7. Cement heater combustion-air and vent pipes to concentric vent
termination assembly. See Figure 26 for proper pipe attachment.
8. Operate heater through 1 heat cycle to ensure combustion-air and
vent pipes are properly connected to concentric vent termination
connections.
fIGure 26.

MultI-concentrIc vent terMInatIons

When two or more appliances are direct vented with concentric
vent terminations near each other, each appliance must be
individually vented. NEVER common vent this appliance. When
two or more appliances are direct vented using concentric vent
terminations, the appliances may be vented as shown in Figure
27 and 28.
Concentric Vent Terminations
for Horizontal Direct Venting.
Concentric Vent Terminations for Vertical
Direct Venting through a roof.
29
fIGure 27.
fIGure 28.