U.S. Boiler Company ASPEN ASPN-320, Installation, Operating And Service Instructions

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107750-01 - 9/17
VII. Venting
E. Assembly of CPVC/PVC Vent Systems
WARNING
Failure to follow this warning could result in a sphyxiation and/or carbon monoxide poisoning. Correct
venting material and installation is required for proper vent operation. PVC Vent Systems must
include at least 30 inches of CPVC and one CPVC elbow between the boiler and PVC vent piping. See
this Section, VII. Venting for complete information.
Use CPVC vent components within any interior space where air cannot circulate freely, including
through vertical or horizontal chase ways, inside a stud wall, in closets and through wall penetrations.
Asphyxiation Hazard. Failure to follow these instructions could cause products of combustion to
enter the building, resulting in severe property damage, personal injury or death.
The use of cellular core PVC (ASTM F891), cellular core CPVC or Radel (polyphenolsulfone) is
prohibited.
All condensate that forms in the vent must be able to drain back to the boiler.
Never leave the boiler in operation without the gas sample cap in place (Figure 7.26).
E. Assembly of CPVC/PVC Vent Systems
1. Assemble the vent system, starting at the boiler:
a. If 4" PVC is to be used for venting, at least one 4" CPVC elbow and at least one 30" straight section of CPVC must be
used before transitioning to PVC. If necessary the 30" straight section of CPVC may be cut in any location and the CPVC
elbow inserted between the two resulting segments. 4" PVC Sidewall Vent Kit, P/N 107039-03, is available and includes
30" CPVC starter and elbow, PVC terminations, and screens.
b. When cutting CPVC or PVC pipe, use a miter saw or a saw designed to cut PVC pipe. Use a miter box or other method to
cut pipe squarely. De-burr both the inside and outside of the cut end.
c. Dry fit all vent components before assembly.
d. The vent adaptor has three different inside diameters. The larger (upper) inside diameter accepts 4" CPVC pipe and is used
in this application (the middle inside diameter accepts 4" nominal PolyPro, Polyflue or InnoFlue). Lubricate the gaskets in
the vent adaptor with water and insert the first piece of 4" CPVC into the vent adaptor until it bottoms out.
Tighten band clamp on vent adapter to secure vent pipe.
e. If 3" CPVC is to be used for the vent system install 4" x 3" CPVC reducing bushing (field supplied), then 30" of 3" CPVC
and CPVC elbow which need to be used before transitioning to 3" PVC. 3" PVC Sidewall Vent Kit, P/N 107039-02, is
available and includes 30" CPVC starter and elbow, PVC terminations, and screens. Otherwise assemble the 4" CPVC
elbow and 30" CPVC piping in Step (a) before transitioning to 3" PVC.
f. Clean all CPVC and PVC components with the appropriate primer before cementing. Cement the vent system together,
starting at the boiler and following the instructions provided on the cans of cement and primer. Use a field supplied
cement and primer that is listed for use with the materials being joined (CPVC and/or PVC). The following, or its
equivalent, may be used to join CPVC to PVC:
• IPS Corporation #P-70 Primer
• IPS Corporation #790 Multi-Purpose Solvent Cement
Always use primer on both the pipe and fitting before applying the cement. Assemble the pipe in accordance with the
instructions on the cans of primer and cement.
g. Assemble the rest of the vent system, being sure to pitch horizontal sections back towards the boiler 1/4"/ft. (21 mm/m)
Support the vent at intervals not exceeding 4 ft.