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 19).
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 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 20) 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
7
Figure 20
nOte: the Chimney On the hOuse illustrateD is tOO lOw.
it shOulD be raiseD tO COmpensate FOr DraFts.
GaLVanIZeD CHIMney Cone
Figure 19
CautIon
neVer ConneCt to an outSIDe CHIMney
unLeSS It IS SuFFICIentLy InSuLateD to
reDuCe tHe aMount oF ConDenSatIon
to a LeVeL tHat WILL not IntereFere
WItH tHe exHauSt oF tHe FLue GaSeS.
