Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 18
Fig 3.1
The smoke pipe connecting the boiler to the chimney flue must be black or stainless, have a minimum
thickness of 24 gauge, and rise a minimum of ¼” per foot of run toward the chimney
(Fig3.1).
Smoke
pipe sections must be attached to one another with a minimum of three sheet metal screws and sealed
with high-temp silicone. The smoke pipe should not contain more than two 90º elbows (45º elbows
are preferred over 90º elbows ).
MASONRY CHIMNEYS: Masonry chimneys must be lined, either with code-approved masonry or
pre-cast refractory tiles, stainless steel pipe, or poured in place liner. Do not use an unlined chimney
FACTORY BUILT CHIMNEYS: Factory built chimneys must be tested and listed for use with solid-
fuel burning appliances to the High Temperature (HT) Standard (2100 ˚F(1148 ˚C )), UL 103, for the
United States. Factory-Built chimneys must be installed as per the manufacturers instructions.
Strong winds blowing across the top of a chimney or a chimney which has a particularly strong natural
draft can cause the Bonus Plus boiler to continue burning (heating) when the draft fan is off. This is
an unlikely scenario, as the blower on a Bonus Plus, used with a thermal storage system, should rarely
be off while a fire is present. If however, an irregular or excessively high draft presents problems, the
solution is the use of a barometric draft regulator or the use of a proper chimney cap that helps in the
prevention of down drafts.
Installation requirements for a barometric damper (draft regulator).
The diameter of the draft regulator must be equal or greater than that of the chimney connector
.
The draft regulator should be installed as close as possible to the boiler, on the chimney con-
nection or on chimney itself.
The draft regulator adjustment should be made with a vacuum gauge, if possible, with the
boiler operating at full output. If the start-up is made in warm weather, a readjustment may be
necessary in cold weather.
If, at the maximum adjustment (maximum opening of the shutter of the draft stabilizer), the
draft is always higher than -0.05” (1.25 mm) of water column, a second draft regulator may be
required.
Recommended draft regulator location
(1)
is shown in
Fig 3.1.
Boiler Installation & Start-up > Preparing the Chimney