Weil-McLain 550 MBH Nstallation And Operation Manual page 44

®
SlimFit Series 3
DIRECT VENT — Vertical
Bird screens are supplied with the boiler. Cut to size if necessary
to fit vent pipe size used.
2. The air piping must terminate in a down-turned 180-degree return
bend as shown in Figure 38, page 43. Locate the air inlet pipe no
further than 2 feet from the center of the vent pipe. This place-
ment avoids recirculation of flue products into the combustion
air stream.
3. The vent piping must terminate in an up-turned coupling as shown
in Figure 38, page 43.
a. Vent must terminate:
At least 6 feet from adjacent walls.
No closer than 5 feet below roof overhang.
At least 3 feet above any forced air intake within 10 feet.
No closer than 12 inches below or horizontally from any
door or window or any other gravity air inlet.
4. The air inlet pipe and vent pipe can be located in any desired posi-
tion on the roof, but must always be no further than 2 feet apart
and with the vent termination at least 1 foot above the air intake.
5. Maintain the required dimensions of the finished termination
piping as shown in Figure 38, page 43.
6. Do not extend exposed vent pipe outside of building more than
shown in this document. Condensate could freeze and block vent
pipe.
Multiple vent/air terminations
1. When terminating multiple SlimFit boilers, terminate each vent/
air connection as described in this section.
Terminate all vent pipes at the same height and all air
pipes at the same height to avoid possibility of severe
personal injury, death or substantial property damage.
2. Place roof penetrations to obtain minimum clearance of 12 inches
between edge of air intake elbow and adjacent vent pipe of another
boiler for U. S. installations (see Figure 2). For Canadian instal-
lations, provide clearances required by CSA B149.1 or B149.2
Installation Code.
3. The air inlet of an SlimFit boiler is part of a direct vent connection.
It is not classified as a forced air intake with regard to spacing from
adjacent boiler vents.
44
COMMERCIAL CONDENSING GAS
(Figure 39)
—
-
FIRED WATER BOILER
(continued)
Termination location — separate pipes —
terminations for multiple boilers
Boiler Manual
Part number 550-100-168/0516