IBC Technologies Inc.
8
VFC 15-150 and VFC 45-225
the combustion air line clearance hole at
the base of the boiler. Such 3’ interval of
2” pipe can be treated as 3” pipe without
reference to its smaller diameter in
calculation of the maximum allowable
vent travel distance. All elbows and tees
at the base of the boiler and at the
termination must be included in the
calculation. On the exhaust side, a 3"x
2” reducer must be placed in a vertical
section of the flue gas vent (within 3’ of
the boiler), to avoid pooling of
condensate. Similar comments apply to
the 15-150’s 2½” PVC venting option –
see below.
Certain installations of the 15-150 model
can employ the 2” vent options. This
would typically involve a 15’lineal foot
run up to the ceiling joists and outside,
using perhaps 3 x 90° elbows on each of
the exhaust and intake. We do not
recommend horizontal runs using 2”
pipe except near the base of the boiler,
upstream of the condensate drain (see
next section). Reason: air friction from
the fast moving exhaust at high-fire in a
2” pipe overcomes gravity on ¼” / foot
vent slope – leaving a pool of
condensate at the next upturned elbow.
Pooling can impair the achievement of
full high-fire rating plate performance.
Again for the 15-150 model only, there
is a further 2½” vent option that offers
some middle ground – it can be applied
to runs of up to 70’ equivalent length for
each side, without the limitation on
horizontal runs as the for 2” option.
If the site requires a horizontal exit
immediately below the boiler – bush out
to 2½” or 3” pipe in the downward
vertical run immediately below the 2”
threaded adaptor, and elbow to
horizontal before splicing in a field
sourced 2½” or 3” reducing tee for
mounting of the condensate trap; this
will slow the exhaust velocity
sufficiently for good drainage and
reduce “spitting” at the vent termination.
In this case, the 3” x ½” (or 2½”x ½”)
reducing tee would replace the 2” tee
and 2” x ½” bushing supplied with the
boiler.
Exhaust venting must slope down to the
trap/drain with a pitch of at least ¼” per
foot so condensate runs towards the trap.
Support should be provided for intake
and vent piping, particularly so for
horizontal runs (follow local code).
Insulate exhaust piping where it passes
through unheated space with appropriate
pipe insulation to prevent freezing of
condensates.
Ensure all venting components are clean
of burrs/debris prior to assembly
. Care is
to be taken to avoid ingestion into the fan of
ABS/ PVC debris left in the combustion air
piping.
All joints must be secured using appropriate
solvent cement to bond the respective pipe
material (Canada: PVC, CPVC or transition
cement approved under
ULC-S636, in
accordance with its manufacturer
instructions;
USA: PVC (ASTM D2564), or
ABS/PVC (D2235) Use transition glue
anywhere that PVC and CPVC are joined.
Follow the cement manufacturer’s
instructions closely when joining various
components.
All vent connections must be liquid and
pressure tight. Test exhaust connections,
under fan pressure with vent blocked, using
a soap/water solution prior to firing.
