Enviro Venice - Manual (Page 8)

8
Operating Instructions
7. What is draft?
Draft is the ability of the chimney to exhaust or draw smoke produced during the normal combustion
process. Too much draft may cause excessive temperatures in the appliance and may damage the
appliance. Inadequate draft may cause backpuffing or “plugging” of the chimney. There is a certain
amount of draft that is required to allow for your stove to function at its’ highest efficiency. A water
column gauge can be used to reference this amount.
8. What can cause a poor draft?
The most common factors for poor draft are:
a) Air supply
b) Environmental conditions
c) Cold chimney temperature
d) Poor chimney installation and maintenance
e) Atmospheric pressure
a) Air supply – Inside the home, normal household appliances such as clothes dryers and forced-air
furnaces compete for air, resulting in air starvation to the fire. This creates a condition in the house
known as negative pressure. When a house experiences negative pressure, the combustion gases
can be drawn from the chimney and into the house. This condition is commonly referred to as down-
drafting. Increased amounts of insulation, vinyl windows, extra caulking in various places and door
seals can all keep heat in but may also make a home too airtight. An easy way to stop negative
pressure in a home is to crack a window in the room containing the stove.
b) Environmental Conditions - High trees, low-lying house location such as in a valley, tall buildings or
structures surrounding your house and windy conditions can cause poor draft or down-drafting.
c) Cold Chimney Temperature - Avoid cold chimney temperatures by burning a hot fire for the first fifteen
to forty minutes, being careful not to over-fire the stove. If any part of the chimney or parts of the
stove start to glow, you are over-firing the stove. Where possible, install a temperature gauge on the
chimney so temperature drops can be seen.
d) Chimney Installation and Maintenance - Avoid using too many elbows or long horizontal runs. Too short
a chimney can cause difficult start-up, dirty glass, back smoking when door is open, and even reduced
heat output. Too tall a chimney may prompt excessive draft, which can result in very short burn times
and excessive heat output. If in doubt, contact a chimney expert and/or chimney manufacturer for
help. Clean chimney, rain caps and especially the spark arrestor regularly, to prevent creosote build-
up, which will significantly reduce chimney draw and possibly a chimney fire.
Note: These instructions are intended as an aid and do not supercede any local, provincial or state
requirements. Check with officials or authorities having jurisdiction in your area.