REASONS for insufficient draft readings:
1. Leaky Chimney – Air leaking in around a loose
fitting clean-out door, flue pipes not tight at the
joints, improper plug openings, or defective ma
-
sonry.
2. Chimney Improper Height – Chimney does not
extend through the roof to a sufficient height to
promote sufficient draft or causes a down draft
-
ing condition to take place. See NFPA 211.
3. Obstructions in the chimney – Check prior to us
-
ing holding a mirror in chimney cleanout door.
This will give an inside view of the chimney.
4. Trees or other topographical barriers – Impending
the chimneys operation or causing a down draft
condition to exist. This can also be caused by ad
-
jacent building or the roof of the same structure
where the chimney is not high enough (Figure 7).
5. Chimney Size – Chimney is not properly sized to
adequately fit the appliance. It is either too small
or too large. Minimum chimney height – 14 foot.
Minimum Diameter – 6 inches.
6. Chimney Offsets – Chimneys with offsets should
not be used. They cause an obstruction to draft
as well as a place for debris to collect.
7. Elbow Restrictions – The flue pipe is connected
to the chimney with too many elbows reducing
the draft the chimney can provide.
8. Multiple Venting – When more than one (1) devise
vents into the same chimney flue.
When smoke rises into the chimney, it will rise in a
spiraling path.
The most important thing to remember about chim
-
neys is their need for maintenance and cleaning. If
chimneys are not cleaned on a regular basis, it ef
-
fects the draft, as well as make an attributing cause
to a chimney fire.
The draft can be improved by using a chimney cone
(figure 8) or by extending the height of the chimney
and reducing the flue area. A cone or chimney exten
-
sion can be made by a local sheet metal shop.
A properly operating chimney will tend to reduce the
amount of creosote that is left deposited.
Instructions for installation, draft measurement, ad
-
justment of the barometric draft regulator.
BOX 422 • TOWER, MN 55790 • USA • Tel (218) 753-2330 • www.lamppakuuma.com
8
Figure 7
Figure 8
nOte: the Chimney On the hOuse illustrateD is tOO lOw.
it shOulD be raiseD tO COmpensate FOr DraFts.
GaLVanIZeD CHIMney Cone
