Burnham K2WTC - Assembly of CPVC;PVC Vent Systems

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107774-01 - 9/17
VII. Venting E. Assembly of CPVC/PVC Vent Systems (continued)
WARNING
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.
Use all CPVC vent components for near-boiler vent piping before transitioning to Schedule 40 PVC
pipe (ASTM 2665) components for remainder of vent system.
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.
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 7.27).
E. Assembly of CPVC/PVC Vent Systems
1. Assemble the vent system, starting at the boiler:
a. If 3” PVC is to be used for venting, a 3” CPVC elbow and the 30” straight section of CPVC must be used before
transitioning to PVC. If necessary the 30” straight section of CPVC may be cut at any location and a CPVC elbow can be
inserted between the two resulting segments.
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tallventcomponentsbeforeassembly.
d. The vent adaptor has three different inside diameters. The larger (upper) inside diameter accepts 3” CPVC pipe and is
usedinthisapplication(themiddleinsidediameteraccepts3”nominalPolyPro,PolyueorInnoFlue,andthesmaller,
lower inside diameter accepts 3” stainless steel). A locking band clamp in the adaptor prevents the vent pipe from coming
out of the adaptor once it is installed and tightened. Lubricate the upper gasket in the vent adaptor with water and insert
therstpieceof3”CPVCintotheventadaptoruntilitbottomsout.Tightenlockingbandclamptosecureventpipe.
e. Assemblea3”CPVCelbowandremainderof30”CPVCpipingbeforetransitioningtoPVC.If3”PVCisused,therst
piece of PVC will either be connected to the CPVC elbow or the end of a section of CPVC vent pipe. In the latter case, a
PVCcouplingmaybeusedtoconnecttherstpieceofPVCtothelastpieceofCPVC.
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eld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tting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. Support the
vent at intervals not exceeding 4ft.
h. Maintain the clearances from the vent pipe outlined in Section VII - A of this manual. If exiting the exterior wall using
PVC pipe, use half of an appropriately sized wall thimble (or a sheet metal plate) on the exterior of the building, to
provide a weather tight seal while maintaining the proper clearance in the wall penetration. Seal the joint between the
pipe and the wall plate using RTV applied on the exterior side of the wall. This sealant must not restrain the expansion of
the vent pipe.
2. Installation of Air Intake System - Start assembly of the PVC air intake system at the boiler. Assembly of the air intake
system is done in the same manner as the vent system except as follows:
a. Drilla7/32”clearanceholeintothefrontsideoftheairintakeadapter.InserttherstpieceofPVCairintakepipe
into the air intake connection and drill a 1/8” tap hole into the PVC which lines up with the 7/32” clearance hole and
secure them together with a #10 x 1” sheet metal screw. Seal the joint between the intake pipe and the adaptor with
RT V.
b. All intake piping may be PVC.
c. There is a 0” minimum clearance between the air intake piping and all types of construction.
d. To the extent possible, pitch horizontal air intake piping towards the outdoors.