2.2 Planning ahead
1. Observe proper combustion air requirements.
2. Provide a firm support system for the chimney fan.
3. Determine the type of system involved.
4. Observe proper safety measures are taken to assure safe use of the wood burning appliances
Combustion air requirements:
Provisions for combustion air must be in accordance with applicable local codes.
If the heating system is installed in an unconfined space
, adequate air will be available via normal infiltration.
If the heating system in installed in a confined space,
(a space with a volume less than 50 cubic feet per
1,000 Btu/hr of input for all
fuel burning equipment) or building construction is unusually tight, adequate air for
combustion must be provided by two openings: one
located about 6” below the ceiling, the other about 6” above the
floor.
Each opening must have a minimum free area as follows:
1. One square inch per 4,000 Btu/hr of input when communicating directly with the outside or through a vertical duct.
2. One square inch per 2,000 Btu/hr when communication through horizontal ducts to the outside.
3. One square inch per 1,000 Btu/hr when ventilation air is provided by openings in doors, etc. to adjoining spaces
having adequate
infiltration.
CAUTION
Adequate fresh air must be provided for combustion; otherwise, improper operation and
inadequate venting of deadly flue gases may result.
Support system for the exodraft chimney fan
Prior to installation of the chimney fan, it must be assured the chimney can
safely carry the weight of the chimney fan.
A steel chimney should be well supported at the roof penetration point.
If the chimney extends more than 20’ above
the roof, the
chimney and the fan should be secured by wires attached on the chimney and on the roof at 2 to 3
different points.
Brick chimneys usually do not need any kind of support to carry the weight of the chimney fan.
System type
Direct connect oil or gas appliances (no draft hood) normally do not require any mechanical draft adjustment.
However, if there are long
horizontal breechings and far between the appliances, it is a good idea to install
mechanical vent dampers, so adjustments of the draft
can be easily made.
Draft hood systems could generally speaking have vent dampers installed. The vent dampers are used to balance
the system and assure
that only a minimum of dilution air is pulled through the draft hoods.
Safety devices
Local codes usually require installation of safety devices, when mechanical draft is provided in an oil or gas fueled
system.
Make sure a differential pressure switch (proven draft switch) is installed to assure that no appliance will fire unless
there is a proven draft.
5
3000270 RS gas and oil 20210818 - international
