Laars heating systems – LAARS Mini-Therm JVi - Install and Operating Manual User Manual
Page 9
LAARS Heating Systems
Page 8
(b)
Vent Termination
A listed vent terminal designed for the type of
pipe being used must complete the vertical run where
it exits the chimney. The vent pipe must extend at
least 3' (.9m) above the highest point where it passed
through the roof. In addition, the vent cap must be at
least 2' (.6m) higher than any portion of a building
within a horizontal distance of 10' (3m). Clearance to
any combustible materials must be maintained as
listed (see Figure 6).
1H-2. Horizontal Venting - Category III
When venting is horizontal, or cannot meet the
requirements of Category I, it can develop positive
pressure and must be installed in accordance with this
section and the specific vent manufacturer’s
instructions.
For best results, horizontal vent systems should
be as short and straight as possible. Material of vent
connectors shall be as follows:
WALL OR
PARAPET
CHIMNEY
CHIMNEY
RIDGE
WALL OR
PARAPET
CHIMNEY
CHIMNEY
RIDGE
10 (3.0) OR
LESS
Figure 6. Vertical Vent Termination.
2 (0.6) MIN.
3 (0.9)
MIN.
10 (3.0)
OR LESS
2 (0.6)
MIN.
3 (0.9)
MIN.
3 (0.9)
MIN.
3 (0.9)
MIN.
2 (0.6)
MIN.
10 (3.0)
MORE THAN 10
(3.0)
MORE THAN 10
(3.0)
NOTE: NO HEIGHT
ABOVE PARAPET
REQUIRED WHEN
FROM WALLS OR
PARAPET IS MORE
THAN 10 FT. (3.0m)
TERMINATION
10 FT. (3.0m)
OR LESS FROM RIDGE,
WALL OR PARAPET
(a)
Vent Connections
The vent system must be gas tight. All seams and
joints must be sealed with silicone sealant or adhesive
tape having a minimum temperature rating of 400°F
(204ºC) (see Table 9 for a list of approved sealing
materials). Use at least three corrosion resistant
screws at each slip joint, when required.
Description
Manufacturer
Product
High Temperature
RTV
Dow Corning
Trade mate
2" (51mm) wide
Aluminum foil tape
- adhesively backed
Venture
Product #3243
2" (51mm) wide
Aluminum foil tape
- adhesively backed
3M
Product #433
Table 9. Vent Sealing Materials.
Materials
Vent Length
In U.S.A.: UL type 304, 316
Up to a maximum of 55' (17m)
or 294-C stainless steel,
of equivalent pipe run
26 gauge minimum.
(including required elbows).
In Canada: Use “BH” vent
type complying with ULC
S-636 Standard.
For each elbow eliminated, add 5' (1.5m) of allowable vent.
Table 10. Horizontal Venting Configuration.
The boiler vent collar must be fastened to the
vent pipe of the same diameter, with rustproof metal
screws no longer than 1/2" (13mm) and sealed with
high temperature (500ºF / 260ºC) silicone sealant. For
larger diameter vent pipes, use a sealed reducer
fastened directly to the boiler collar and seal all joints
as indicated in Figure 7. Allow the sealant to cure for
24 hours before operating the boiler.
The entire vent system must not exceed the size
specified in Table 10.
The following criteria must be observed:
1.
Attach a vertical pipe at least 12" (305mm) high
to the boiler outlet before the horizontal run if
run exceeds 5 feet (see Figure 7).
2.
Support the vent run at 3' (.9m) intervals with
overhead hangers.
Dimensions in feet (m).
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