HS Tarm 2000, Installation And Operation Manual

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O
UTSIDE
C
OMBUSTION
A
IR
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1.
Provision for outside combustion air may be necessary to ensure that fuel-burning appliances
do not discharge products of combustion into the house. Guidelines to determine the need for
additional combustion air may not be adequate for every situation. If in doubt, it is advisable to
provide additional air
2. Outside combustion air may be required if:
(a) the solid-fuel-fired appliance does not draw steadily, experiences smoke roll-out, burns
poorly, or back-drafts whether or not there is combustion present:
(b) existing fuel-fired equipment in the house, such as fireplaces or other heating appliances,
smell, do not operate properly, suffer smoke roll-out when opened, or back-draft whether or
not there is combustion present:
(c) any of the above symptoms are alleviated by opening a window slightly on a calm
(windless) day:
(d) the house is quipped with a well-sealed vapor barrier and tight fitting windows and/or has
any powered devices which exhaust in the house.
(e) there is excessive condensation on windows in the winter; or
(f ) a ventilation system is installed in the house.
If these or other indications suggest that infiltration air is inadequate, additional combustion air
should be provided from the outdoors.
3. The HS-Tarm boilers are not suitable for direct connection of outside air. The outside air
should be ducted to no closer than 12” from the boiler. A 6” duct should be large enough for all
HS-Tarm boilers unless the duct run is over 25 feet.
4. A mechanical ventilation system: If the house has a mechanical ventilation system (air change
or heat recovery), consider the following two issues:
( I ) the ventilation system may be able to provide sufficient combustion make-up air for
the solid-fuel-fired appliance; and
(II ) the householder should be informed that the ventilation system may need to be re-
balanced by a ventilation technician after installation of the solid-fuel-fired appliance.
5. It is normal practice to terminate the outside combustion air duct at floor level.
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