Weil-McLain 4 Series Manual page 24

®
Series 4
Vertical vent/air termination:
5. Maintain clearances to vent termination as given below:
a. Vent must terminate:
At least 6 feet from adjacent walls.
No closer than 5 feet below roof overhang.
At least 7 feet above any public walkway.
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.
b. Air inlet must terminate at least 6 inches above the roof or
snow line and at least 12 inches below the vent termina-
tion as shown in Figure 22, page 23 .
c. Do not terminate closer to 4 feet horizontally from any
electric meter, gas meter, regulator, relief valve or other
equipment. Never terminate above or below any of these
within 4 feet horizontally.
6. Locate terminations so they are not likely to be damaged by
foreign objects, such as stones or balls, or subject to buildup
of leaves or sediment.
7. Do not connect any other appliance to the vent pipe or mul-
tiple boilers to a common vent pipe.
Prepare roof penetrations
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:
2¾" hole for 2"
4" hole for 3"
5" hole for 4"
b. Insert a galvanized metal thimble in the vent pipe hole.
3. Space the air and vent holes to provide the minimum spacings
shown in Figure 22, page 23 .
4. Follow all local codes 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.
Termination and fi ttings
1. Prepare the vent termination elbow and the air termination
elbow ( Figure 22, page 23 ) by inserting bird screens. Bird
screens must be purchased separately. See the parts list at the
end of this manual for part numbers.
a. If using 3-inch piping for an Ultra-230, cut a 4-inch bird
screen by placing 3-inch fi tting on screen and cutting
around it as a template.
2. The air piping must terminate in a down-turned 180-degree
return bend as shown in Figure 22, page 23 . Locate the air
inlet pipe no further than 2 feet from the center of the vent
pipe. This placement avoids recirculation of fl ue products
into the combustion air stream.
24
gas-fired water boiler — Boiler Manual
Separate pipes
Figure 23
3. The vent piping must terminate in an up-turned coupling as
shown in Figure 22, page 23 . 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 2 feet apart and with the vent
termination at least 1 foot above the air intake.
4. Maintain the required dimensions of the fi nished termination
piping as shown in Figure 22, page 23 .
5. 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 Ultra 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 installations, provide clearances required by
Natural Gas and Propane Installation CAN/CSA B149.1 or
B149.2 Installation Code.
3. The air inlet of an Ultra boiler is part of a direct vent con-
nection. It is not classifi ed as a forced air intake with regard
to spacing from adjacent boiler vents.
(continued)
( Figure 23 )
Part number 550-100-400/0119