Install Instructions

18
107750-01 - 9/17
1. Listed Vent Systems and Materials – The following materials and vent systems may be used to vent this boiler:
• CPVC – Use only CPVC listed to ASTM F441. In Canada, this pipe must also be listed to ULC S636.
• PVC – PVC may be used only as permitted in this manual. All PVC must be listed to ASTM D2665. At least 30" of
CPVC pipe, and at least one CPVC elbow, must be installed between the boiler’s vent connection and the PVC pipe. Use
of foam core PVC is not permitted for venting. PVC vent pipe may not be used to vent this boiler in Canada.
• DuraVent PolyPro - ULC S636 listed PolyPropylene special gas vent system.
• Selkirk Polyue - ULC S636 listed PolyPropylene special gas vent system.
• Centrotherm InnoFlue SW - ULC S636 listed PolyPropylene special gas vent system.
• DuraVent FasNSeal Flex-UL 1738 listed Stainless Steel Special gas vent system.
• Use PVC and/or CPVC for the air intake system. PVC may be used for all air intake piping between the intake terminal
and the boiler.
• When CPVC and/or PVC pipe is used, it must be joined using primer and cement that is listed for use with the pipe
material being joined (PVC, CPVC, or CPVC to PVC).
2. Vent Kits Available for Use with this Boiler - The following vent kits are available for CPVC/PVC vent systems installed
with this boiler in the USA:
• 107039-03 - 4" CPVC/PVC Vent Kit
These kits include the following:
(1) 30" CPVC Straight Pipe
(1) 90 degree short bend CPVC Elbow
(1) Straight PVC Coupling (for exhaust terminal)
(1) 90 degree PVC Elbow (for intake terminal)
(2) Rodent screens
The CPVC Pipe and elbow supplied with these kits are not listed to ULC S636 and may not be used in Canada.
3. Maximum Vent and Air Intake Lengths - The maximum length of the vent air intake piping depends upon the vent option
selected and the boiler size. See Tables 7.5, 7.13 or 7.21 for the maximum vent lengths. These maximum lengths apply
to both the vent and intake piping (e.g. Option 1 may have up to 60ft of intake and 60ft of vent piping). For all vent
systems, the lengths shown in Tables 7.5, 7.13 and 7.21 are in addition to the rst 90° elbow. If more elbows are desired,
the maximum allowable vent length must be reduced by the amount shown in Table 7.1 for each additional elbow used.
Termination ttings are never counted.
It is recommended that all eld supplied PVC or CPVC elbows be “1/4 Bend” (Sanitary 90° El) or “Long Sweep 1/4
Bend” type elbows (Figure 7.2). In this manual “sanitary” and “long sweep” elbows are treated as having the same equivalent
length.
Example:
A 4" twin pipe horizontal CPVC/PVC vent system is planned for a horizontally vented 320MBH model which has the
following components in the vent system:
• 1 ft CPVC Straight Pipe
• 90 CPVC Elbow (short bend)
• 1-1/2 ft CPVC Straight Pipe
• Coupling
• 10 ft PVC Straight Pipe
• 90 PVC Elbow (Sanitary Elbow Design)
• 15 ft PVC Straight Pipe
• PVC Coupling Terminal
The Vent Option #2 column in Table 7.5 describes a horizontal direct vent system using 4" CPVC and PVC pipe. From this
column,weseethattheboilermayhaveaventlengthofupto135ft.TherstCPVC90degreeelbowisnotconsidered.From
Table 7.1, we see that the equivalent length of the 90 PVC Sanitary elbow is 9ft and that the equivalent length of the coupling
is 0ft. The total equivalent length of the planned venting system is therefore:
1ft(StraightCPVC)+0ft(rstshortbendCPVC90Elbow)+1.5ft(StraightCPVC)+0ft(Coupling)+10ft(StraightPVC)
+ 9ft (PVC 90 Sanitary Elbow) + 15ft (Straight PVC) + 0ft (Coupling Terminal) = 36.5ft.
Since Table 7.1 shows a maximum allowable vent length of 135ft, the planned vent system length is acceptable
The ex venting used on some of the Vertical Twin Pipe and Split Vent Options also reduces the maximum allowable vent
length. See Sections VII-C or VII-D for details.
VII. Venting A. Vent System Design (continued)