Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 4 – INITIAL START-UP
OMM-0082_0J
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
Page
59
of
192
GF-130
Ph.: 800-526-0288
05/21/2014
NATURAL GAS Combustion Calibration –
Continued
Figure 4-3: Gas Pressure Adjustment Screw Location
11.
Using the ▲ arrow key, increase the valve open position to
100%
. Verify that the gas
pressure on the downstream side of the SSOV settles within the range of
2.0” W.C. ±
0.4” W.C.
Readjust the gas pressure if necessary.
12.
With the valve position at 100%, insert the combustion analyzer probe into the flue probe
opening and allow enough time for the combustion analyzer reading to stabilize.
13.
Compare the oxygen readings on the combustion analyzer to the on-board O
2
sensor
value displayed in the Operating Menu of the C-More Control Panel.
If the values differ by
more than ±1.5% and your combustion analyzer is correctly calibrated, the on-board
O
2
sensor may be defective and need to be replaced.
14.
Compare the measured oxygen level to the oxygen range shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the values
shown. If you are not in a “NOx-limited” area and/or do not have a NOx measurement in
your analyzer, set the oxygen (O
2
) at
5.5% ± 0.5%.
Combustion Calibration Readings
Valve Position
Oxygen (O
2
) %
Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
100%
5% - 6%
<20 ppm
<100 ppm
15.
If the oxygen level is not within the required tolerance, the gas pressure on the
downstream side of the SSOV must be adjusted using the gas pressure adjustment
screw on the SSOV (Figure 4-3). Slowly rotate the gas pressure adjustment
(approximately 1/4-turn increments). Allow the combustion analyzer to stabilize following
each adjustment. Clockwise rotation reduces the oxygen level, while counterclockwise
rotation increases the oxygen level.
16.
Once the oxygen level is within the specified range at 100%, record the O
2
, NOx and CO
readings on the Combustion Calibration Data Sheets provided with the unit.
17.
Lower the valve position to
80%
using the ▼arrow key.
BRASS HEAD CAP
(Remove to access
Gas Pressure
Adjustment Screw)
