service
True CO2!
Air Leaks into Both Old and New Units
by George Lanthier*
J
ust attended a trade show and have
been doing a lot of classes and in a
lot of discussions with my customers, friends and students an issue
came to the top. No, it's not draft,
but that really is the most important piece
of the combustion puzzle, ALWAYS! In a
way I guess it is draft related because this
has to do with air leaks and so that means
it's draft related because if air is involved,
it's draft!
This has to do with air leaks into both
old and new units that turn into low CO2
readings at the breech from air leaks into
heat exchangers, boilers, furnaces and
water heaters. That means it's also fuel
neutral and can affect coal units, gasburners, oilburners and wood pellet burners
(Figure 1).
We all know that it is important that
if a unit has been assembled in the field,
the seals around sections, pouch plates,
burner gaskets, fire doors, sight holes,
smokehoods, etc. be airtight. It is also a
prime indicator in an older unit that if
all of the other reasons for low CO2 have
been eliminated, the heat exchanger be
checked with a smoke candle. Although
this procedure may require part or the
entire jacket be removed, it will still take
you less time than is required to fight a
lawsuit or clean a basement of soot.
One of the easiest ways to check for
air leakage through the heat exchanger is
to perform an overfire CO2 test. Taking
a CO2 test through the fire door or peephole confirms that there are no air leaks
or proof positive that there are. This test
must be taken directly over the fire and is
performed following these steps:
Measure or calculate the distance from
the front of the unit to the center of the
chamber.
18
SEPTEMBER 2013 | FUEL OIL NEWS | www.fueloilnews.com
Figure 1
