MODEL 300 COMBUSTION ANALYZER
3-6
Instruction 24-9223
3.2
GAS SAMPLING POINTS
The Model 300 Combustion Analyzer requires a
3
/
8
" (9.5 mm) minimum
diameter sampling hole to accommodate the analyzer’s probe-stop.
Locate the sampling point downstream from the last heat exchanger, and
upstream from any source of dilution.
Important:
As the distance between
the heat exchanger and the sampling
point increases, the calculated combus-
tion efficiency will falsely increase due
to heat loss in the flue or stack.
For residential and light commercial
combustion equipment applications, the
following recommendations are applicable:
•
Oil Burners
– Locate sampling hole at
least 12" downstream from the furnace
breeching, and at least 6" upstream from
the furnace side of the draft regulator.
•
Gas Burners
– Locate sampling hole at
least 6" upstream from the furnace side
of the draft diverter on gas conversion
units. For gas-designed equipment, the
probe may be inserted down into the flue
through the draft diverter or hood.
3.3
INSTALLING THE PROBE
Screw probe stop into gas-sampling hole (Fig. 3-3); then insert probe
through hole in probe stop.
Push probe into stack to desired depth; then tighten probe-stop-thumb
screw to lock probe in place.
Figure 3-2.
Sample Point
D R A F T
D I V E R T E R /
R E G U L A T O R
S A M P L E
P O I N T
F U R N A C E
B R E E C H I N G
F L U E G A S F L O W
( U p s t r e a m )
( D o w n s t r e a m )
