Part number 550-142-058/0811
WM97+
gas
-
fired
water
boiler
—
Boiler Manual
26
DIRECT VENT —
Sidewall concentric
(continued)
Figure 26
Termination location — concentric
termination — multiple boilers —
clearance from vent of one to air intake of
the next
Figure 27
Installing and supporting the concentric
sidewall vent assembly
LEGEND
1
Vent pipe
2
Air pipe
3
Wall
4
Outer thimble plate
5
Supports every 5 feet or
per vent pipe mfr’s in-
structions
6
Wall brace, by installer,
(or see vent pipe mfr’s
instructions)
7
Thimble, by installer
8
Rain cap
9
Rain cap ribs must butt
against outer thimble
plate or wall opening
Install termination — concentric pipes
1. Assemble the vent termination as described for concentric termi-
nations, on page 31.
If necessary, you can shorten the lengths of the inner and
outer pipes for a shorter finished assembly. But you must
ensure the pipes butt correctly at both ends. Failure to
properly assemble the concentric termination can result
in flue gas recirculation, causing possible severe personal
injury or death.
2. Wall penetration:
a. Preferably, use a thimble with a 4½-inch hole. If not using a
thimble, carefully use a hole saw to cut a hole not larger than
4¾ inches in diameter through the wall. The finished hole
must provide a solid stop for the rain cap ribs, as shown in the
inset to Figure 27.
Ensure that the wall material is strong enough to pre-
vent the rain cap from being pushed inward if struck or
pushed from the outside.
3. Secure the termination in place so the rain cap will butt against the
outside wall or outer thimble plate as shown in Figure 27, page 26.
4. Before beginning vent and air piping from the boiler to the con-
centric termination, mount and secure the concentric termination
as shown in Figure 27, page 26.
The vent and air piping must be securely supported, and
must not rest its weight on the boiler fittings. Failure to
properly support the vent and air piping could result in
vent piping damage, resulting in possible severe personal
injury, death or substantial property damage.
The supports/bracing used must support the termination
assembly to prevent slippage or movement. See instruc-
tions provided with concentric kit for details.
The clamps used on the outside of the termination pipe
must not cut into the pipe or contain sharp edges that
could cause a crack to form.
When inserting the partially-assembled termination
kit through the wall penetration, wrap plastic or other
protection over the end of the exposed assembly to pre-
vent debris from entering the pipes. If the air passages
become blocked, the boiler will not operate. Once the
rain cap has been cemented to the assembly, there is no
way to correct the problem. The assembly would have
to be replaced if it were cut to be removed and cleaned.
Altering the assembly in any way could result in severe
personal injury or death due to toxic flue product emis-
sions.
When using AL29-4C stainless vent pipe, use the vent
pipe manufacturer’s PVC adapter when connecting to a
PVC concentric vent attachment.
5. After the assembly has been positioned in the opening and all sup-
ports have been attached, install a bird screen (purchased separately
if not included with the kit) and rain cap as follows:
a. Place the bird screen on the end of the inner pipe as in Fig-
ure 33, page 31, or per concentric kit instructions for poly-
propylene kits.
b. Cement the rain cap in place as shown.
See notices on previous page.
