CSA RA 350 - Page 22

Form I-RA/D 350/500, Page 22
Check-Test
Continued
WARNING: If there is insufcient draft, it will create
a back pressure resulting in oil fumes in the building
and/or pulsating when the burner starts and stops. It
may cause excess deposits of soot and overheat the
heat exchanger resulting in premature failure of the
chamber. THIS TYPE OF FAILURE IS NOT COVERED
UNDER THE WARRANTY.
To correct this problem, the height of the chimney may need increased
and/or a UL or CSA/ULC listed draft inducer may be installed.
If a draft inducer is used, a draft proving switch must be installed to shut
off the fuel supply to the burner in the event of the failure of the draft
inducer.
CAUTION: If there is a backdraft or downdraft, do not
continue operation of the heater until the situation is
corrected. Equipment and/or property damage could result.
Back pressure (backdraft or downdraft) may be caused by
the chimney being lower than surrounding objects, such
as buildings, hills, trees, rooftops, etc. It may be caused by
an exhaust fan in the building. The air intake in the room
where the heater is installed must be of sufcient size so
that there is no change in the draft reading in the ue with
the exhaust fan running.
If there is too much draft, it could cause ignition problems, erratic burner,
and loss of thermal efciency. To correct this problem adjust the barometric
damper to reduce the draft.
Check combustion and air band and shutter settings.
Certain installation conditions may necessitate a change in these set-
tings. We recommend that the need for a change be determined by the
use of instruments. When obtaining the CO
2
readings, do so with
a hot system that has the correct draft settings. With a clean heat
exchanger, these settings should result in Bacharach smoke
readings not greater than No. 1 and CO
2
reading in the range
listed below.
IMPORTANT: If it is necessary to change the air band
settings, the draft measurement must be rechecked.
RAD350
Reference Air Shutter and Air Band Settings
Size
Elevation
(feet)
Air
Shutter
Air
Band
CO
2
Range
350 0-3000 #5 #5 10.5 - 11.5%
500 0-3000 #5 #3 11 - 12%
350H >3000-7000 #4 #2 11.5 - 12.5%
These are settings from which a qualied service-
man/installer must make adjustments.
Air Shutter
Air Band