Weil-McLain Evergreen EVG 70 Manual page 35

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DIRECT VENT —
Prepare roof pen etrations
1. Air pipe penetration:
a. Cut a hole for the air pipe. Size the air pipe hole as close as
desired to the air pipe outside diameter.
2. Vent pipe penetration:
a. Cut a hole for the vent pipe. For either combustible or
noncombustible construction, size the vent pipe hole at least
0.4" larger than the vent pipe diameter.
b. Insert a corrosion resistant metal thimble in the vent pipe hole.
3. Space the air and vent holes
shown in Figure 26, page 28 .
4. Follow all local codes and vent pipe manufacturer's instructions
for isolation of vent pipe when passing through fl oors, ceilings
and roofs.
5. Provide fl ashing and sealing boots sized for the vent pipe and air
pipe. Follow all vent pipe manufacturer's instructions.
Termination and fi ttings
1. Prepare the vent termination elbow and the air termination elbow
( Figure 36, page 34 ) by inserting bird screens. Bird screens must be
purchased separately. See the parts list at the end of this manual
for part numbers.
2. The air piping must terminate in a down-turned 180-degree
return bend as shown in Figure 36, page 34 . Locate the air inlet
pipe no further than 12 inches from the center of the vent pipe.
This placement avoids recirculation of fl ue products into the
combustion air stream.
3. The vent piping must terminate in an up-turned coupling as shown
in Figure 36, page 34 . The top of the coupling must be at least 12
inches above the air intake. The air inlet pipe and vent pipe can be
located in any desired position on the roof, but must always be no
further than 12 inches apart (center to center) and with the vent
termination at least 12 inches above the air intake.
4. Maintain the required dimensions of the fi nished termination
piping as shown in Figure 36, page 34 .
5. Do not extend exposed vent pipe outside of building more than
shown in this document. Condensate could freeze and block vent
pipe.
Part number 550-100-191/0917
as-fired water boiler —
Vertical with separate pipes
See notices on previous page.
no closer than the minimum spacings
Boiler Manual
70/110/155
Figure 37 Terminations for multiple boilers
Also maintain maximum distances between
the vent and air pipes for each boiler as shown
in Figure 26, page 28 .
(continued)
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