LAARS Mighty-Stack TL00-199 - Installation, Operation and Maintenance Instructions - Manual (Page 9)

Mighty Stack Water Heater Page 9
Figure 8. Horizontal Venting.
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 8. 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 8).
• 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
(1 cm 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.
(b) Vent Termination
A side wall vent terminal (hood) must be used
when the water heater is vented through a side wall.
Use Laars Part Number D2004300, 4" (102 mm) dia.
The vent hood provides a means of installing vent pipe
through the building wall, and must be located in
accordance with ANSI Z223.1/NFPA 54, or in Canada
CAN/CGA-B149 and local applicable codes (see
Figure 9.)
Locate the vent terminal so that it cannot be
blocked by snow. Most codes require that the
termination be at least 12 inches (305 mm) above
grade, but the installer may determine it should be
higher depending on local conditions.
1M. Water Piping
1. To prevent damage to the unit, all soldering must
be done before making any connections to the
heater or the tank.
Figure 7. Vertical Vent Termination.