SERVICE
all samples and be in an upright position
when stored. Also, instruments should be
at room temperature when in use. Under
adverse conditions, disregard first CO2 test
as a warm-up/ cool-down procedure.
Proper use especially hinges on the
proper insertion depth of sampling
tubes.
The tubes should end at roughly the
center of the pipe to trap the hottest and
most highly concentrated flue gas samples.
The thermometer's bimetal is at the end
of the probe and in the case of electronic
instruments; the thermocouple is also at
the end of the sending tube. One manufacturer's use of spring clips is especially
conducive to obtaining the desired insertion depth.
When using most thermometers, most
of the units found in the manufacturer's
kits have stem lengths of 5 inches. This
allows for accurate temperature readings
for up to and including a 10-inch diameter
fluepipe. When taking temperature readings on a larger pipe, a longer stem on the
instrument is preferred. Bacharach makes a
thermometer with an 11-inch stem and this
longer stem will properly accommodate up
to a 22-inch fluepipe.
Temperature of flue gas has always
been, and still is, one of the single most
important tests we perform on heating
plants. From knowing that a one percent
CO2 change will affect temperature 25°F,
we can make burner adjustments with
accurate thermometers very easily. So, it is
very important that we use and maintain
the equipment to the best of our ability.
Finally, in this discussion about the
basic use of instruments, the calculators
or slide rule charts and tables should be
touched upon. Some tables are temperature compensated at 50°F, but others
require the subtraction of ambient temperature, i.e. the average temperature of
the basement or boiler room.
Subtraction of 100°F should only be
used when measured ambient temperature is 80°F or better.
If your test is questioned, it is probably
better in these days of consumer awareness and energy auditing to be lower than
higher. A good way to confirm basement
temperature is to simply carry in your kit a
regular wall thermometer, such as the ones
your company may already give away to
new customers.
See ya!
l FON
***George Lanthier is the owner of Firedragon
Academy, a Massachusetts Certified School teaching both gas and oil and a publishing and consulting
firm. He is the author of over 50 books and manuals
on gas and oil heating and HVAC subjects. He is a
CETP, NATE, NORA, PMAA and PMEF Proctor
and a Massachusetts Certified Instructor. He can
be reached at 608 Moose Hill Road, Leicester, MA
01524. His phone is 508-421-3490 and his website
can be found at www.FiredragonEnt.com
www.fueloilnews.com | FUEL OIL NEWS | NOVEMBER 2013
17
