Weil-McLain Ultra Commercial Installation And Start-Up Manual page 42

COMMERCIAL GAS
DIRECT VENT — Sidewall
4. The air inlet of an Ultra 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.
5. Combustion air (NOT vent piping) can be manifolded as shown
in Figure 31, page 37.
Prepare wall 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 non-
combustible construction, size the vent pipe hole at least 0.4"
larger than the vent pipe diameter:
7" hole for 6" PVC
9" hole for 8" PVC
b. Insert a galvanized metal thimble in the vent pipe hole as
shown in Figure 40.
3. Sidewall termination plates must be provided by the installer.
4. Follow all local codes for isolation of vent pipe when passing
through floors or walls.
5. Seal exterior openings thoroughly with exterior caulk.
Termination and fittings
1. Prepare the vent termination elbow and the air termination elbow
(Figure 40, page 42) by inserting a bird screen in each. Bird screens
are supplied with the boiler. Cut to size if necessary to fit vent pipe
size used.
2. When completed, the air termination elbow must be oriented
at least 20 inches (and no more than 36 inches) below the vent
termination, and at least 12 inches above grade or snow line as
shown in Figure 35, page 40.
3. You can orient the vent termination elbow either directly outward
or 90 degrees away from the air inlet elbow as shown in Figure 35,
page 40.
4. Maintain the required dimensions of the finished termination
piping as shown in Figure 35, page 40.
5. Do not extend exposed vent pipe outside of building more than
shown in this document. Condensate could freeze and block vent
pipe.
If the vent/air pipes are extended out beyond the wall,
install a coupling at the exit opening, with the coupling
butted against the outside plate. Then continue vent/air
piping from the coupling.
Do not exceed the maximum lengths of the outside vent
piping shown in Figure 35, page 40. Excessive length ex-
posed to the outside could cause freezing of condensate
in the vent pipe, resulting in potential boiler shutdown.
In extremely cold climates, install an insulated chase
around the vent piping, particularly when using longer
lengths. The chase must allow for inspection of the vent
pipe, and insulation must be protected from water.
42
-
FIRED WATER BOILER
— Boiler Manual
(continued)
DIRECT VENT — Sidewall — termination
assembly (all parts by installer, except the
bird screens)
1 Vent piping
2 Air piping
3 Cover plates
4 Galvanized thimbles
5 Bird screen (air)
6 Air inlet elbow
7 Elbow
8 Nipple
9 Elbow (vent termination)
10 Alternate elbow orientation
11 Bird screen (vent termination)
Part number 550-100-086/0809