Locations for Checking Draft
Furnace manufacturer may require measurement of draft (a) in
fl
ue between regulator and furnace or (b) over
fi
re between com-
bustion space and heat exchanger (Figure 4). Locate sampling
hole in
fl
ue 6” or more from draft regulator or damper toward
furnace. Use awl with ¼ shank for forming draft hole in light
sheet metal. Make over
fi
re measurement through blot hole in
door or through air louvers. If necessary, drill ¼ hole. In case of
over sized hole or masonry setting, draft tube (replace with
1/8’ pipe if necessary) should be inserted several inches beyond
inside surface of
fl
ue pipe or furnace wall. For detailed instruc-
tions on check locations, see manufacturer’s service or installa-
tion manual.
6
Figure 3. Mounting Draft Gauge
Figure 4. Draft Gauge Locations
Measuring Draft
Allow furnace to operate for several minutes, unwrap hose, place
gauge on reasonably level surface, check zero, insert metal draft
tube through draft hole. After about 30 seconds read draft from
gauge scale.
Correct Draft
Recommendations for draft required for good performance must
be obtained from the heating equipment manufacturer’s instal-
lation or service manual. Some common causes of poor draft are
shown in “Common Chimney Troubles”.
Maintenance
Do not oil this gauge. Protect the gauge from shock, vibration
and exposure to excessively high temperatures.
7
Summary of Contents for DRAFT GAUGE
Page 5: ...8...
