Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
APPENDIX M – ULTRA-LOW NOx CALIBRATION
Page
186
of
192
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0082_0J
05/21/2014
Ph.: 800-526-0288
GF-130
Ultra-Low NOx Natural Gas Combustion Calibration –
Continued
Figure M-1. 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 ± 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 ±0.5%, have your combustion analyzer calibration checked as soon as possible. If the
readings differ by more than ±1.5%, use the on-board O
2
sensor to calibrate the unit. Have
your combustion analyzer serviced.
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.
Ultra-Low NOx Combustion Calibration Readings
Valve Position
Oxygen (O
2
) %
Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
100%
5% - 7%
<9 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 L-1). 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.
TYPICAL SSOV ACTUATOR WITH REGULATOR
BRASS HEAD CAP
(Remove to access gas
pressure adjustment
screw)
