Williamson-Thermoflo GWC-070 Manual page 50

GWC -
gas fired water boiler
DIRECT EXHAUST — Sidewall
Where the vent penetrates an outside wall, the annular
space around the penetration must be permanently
sealed using approved materials to prevent entry of
combustion products into the building.
1. Wall penetration:
a. Cut a rough opening large enough to clear the diameter
of the metal thimble used.
b. The metal plates can be field fabricated or can be made by
cutting a W-T sidewall termination plate in half — two
2-hole plates are supplied with the boiler.
c. The W-T plate hole diameters are 3.14" for holes as is. Use
as is for 3" AL29-4C pipe. Remove knockout to provide
3 ⁄ " hole for 3" PVC pipe.
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d. If field fabricating the plates, the hole diameters in the
metal plates must be 3
pipe and coupling (or elbow) — size hole large enough to
clear vent pipe, but small enough to prevent the termina-
tion coupling (or elbow) from being pushed through.
e. Insert a galvanized metal thimble (by installer) in the vent
pipe hole as shown in Figure 58.
2. Follow all local codes for isolation of vent pipe when passing
through floors or walls.
Termination and fittings
1. If using a coupling or elbow for the termination, prepare the
vent termination fitting (Figure 58, page 50) by inserting a
bird screen, unless using an AL29-4C termination fitting with
integral screen. Bird screens are not supplied with the GWC
boiler. Purchase separately from Williamson-Thermoflo. See
Figure 92, page 87 for part numbers.
2. You can install the vent termination using either of the con-
figurations shown in Figure 57, page 49.
3. Maintain the required dimensions of the finished termination
piping as shown in Figure 57, page 49.
4. Do not extend exposed vent pipe outside of the building more
than shown in this document. Condensate could freeze and
block vent pipe.
LEGEND for Figure 58
1 Vent piping
2 Sidewall termination plates — two 2-hole plates are supplied with the
boiler — one of these can be cut in half for use in direct exhaust venting
or the plate can be field fabricated) — plate holes can be used as is for 3"
AL29-4C vent pipe. Remove knockout to provide clearance hole for 3" PVC
pipe.
3 Galvanized thimble
4 Vent termination elbow
5 Bird screen — two bird screens are supplied with each boiler
6 Extend vent pipe through outside plate enough to attach termination
coupling (or elbow when snorkeled).
7 Snorkel option (to elevate vent termination) — requires bird screen (see
Figure 92, page 87 for part numbers)
8 Coupling option — requires bird screen — two bird screens are supplied
with each boiler
50
— Boiler Manual
5 ⁄ " for PVC pipe. For AL29-4C vent
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(continued)
DIRECT EXHAUST — Sidewall — termination
Figure 58
assembly and termination options — all parts
by installer except where shown otherwise
Part number 550-142-056/0411