Williamson-Thermoflo GWC-070 Manual page 42

GWC S 2
erieS gaS
DIRECT VENT —
3. Space the air and vent holes to provide the minimum spacings
shown in Figure 49, page 41.
4. Follow all local codes for isolation of vent pipe when passing
through floors, ceilings and roofs.
5. Provide flashing and sealing boots sized for the vent pipe and air
pipe.
Termination and fittings
1. Prepare the vent termination elbow and the air termination elbow
(Figure 49, page 41) by inserting bird screens. Two bird screens are
supplied with the boiler.
2. The air piping must terminate in a down-turned 180-degree re-
turn bend as shown in Figure 49, page 41. Locate the air inlet pipe
no further than 12 inches from the center of the vent pipe. This
placement avoids recirculation of flue products into the combus-
tion air stream.
3. The vent piping must terminate in an up-turned coupling as shown
in Figure 49, page 41. The top of the coupling must be at least 1 foot
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 and with the vent termination at least 1 foot
above the air intake.
4. Maintain the required dimensions of the finished termination
piping as shown in Figure 49, page 41.
5. Do not extend exposed vent pipe outside of building more than
shown in this document. Condensate could freeze and block vent
pipe.
42
-
fired water boiler
Vertical with separate pipes
— Boiler Manual
Figure 50
Terminations for multiple boilers
Also maintain maximum center-to-center
distances between the vent and air pipes for
each boiler as shown in Figure 49, page 41.
(continued)
Part number 550-142-786/0712