LAARS Mighty-Stack TL80-199 - Installation, Operation and Maintenance Instructions - Manual (Page 9)

Mighty Stack Water Heater Page 9
Figure 9. Horizontal Venting.
Outside wall
Vent
system
Water
heater
Thimble
Boiler venting detail
Caulk entire joint
including the screws
Sheet metal
screws
*12" Min.
(305 mm)
* When horizontal run
exceeds 5 ft. (1.5 m)
Figure 8. Vertical Vent Termination.
For best results, a horizontal vent system should
be as short and straight as possible. The materials
used in the vent connectors should be as listed in
Table 7.
Description Manufacturer Product
High Temperature
RTV Dow Corning Trade Mate
2" (51 mm) wide
aluminum foil tape, Venture Product #3243
backed with adhesive
2" (51 mm) wide
aluminum foil tape 3M Product #433
backed with adhesive
Table 6. Vent Sealing Material.
In USA: Up to a maximum of
Use UL type 304, 316 or 40 feet (12 m) of equiv-
29-4C stainless steel, alent pipe run (including
26 gauge minimum. required elbows).
In Canada:
Use “BH” vent type
complying with ULC
S-636 Standard.
Table 7. Vent Connector Materials.
The water heater vent collar must be fastened to
vent pipe of the same diameter, with rustproof metal
screws no longer than 1/2" (13 mm) and sealed with
high temperature 500°F (260°C) silicone sealant. For
larger diameter vent pipes, use a sealed reducer
fastened directly to the water heater collar and seal all
joints as indicated in Figure 9. Allow the sealant to
cure for 24 hours before operating the water heater.
The entire vent system must not exceed the size
specified in Table 8.
The following criteria must be observed:
• Attach a vertical pipe at least 12 inches (305
mm) high to the water heater outlet before the
horizontal run if run exceeds 5 feet (1.5m)
(see Figure 9).
• Support the vent run at 3-foot (1 m) intervals
with overhead hangers.
• Pitch down the vent run, toward the vent
terminal (hood), at a rate of 1/4 inch per foot
(1cm per 50 cm).
• Do not locate any joint screws at the bottom of
the vent run.
No. of Horizontal Run
Diameter Elbows Length*
4" (102 mm) 4 20' (6 m)
*For each elbow eliminated, add 5 feet (1.5 m) of allowable vent.
Table 8. Horizontal Venting Configuration.