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
61
of
192
GF-130
Ph.: 800-526-0288
05/21/2014
NATURAL GAS Combustion Calibration –
Continued
*NOTE
Set the Valve Position at 18% but make adjustments to the Combustion
Calibration value designated as 16%.
NOTE
If NOx readings exceed the target values shown (<20 ppm), increase the
O
2
level up to 1% higher than the listed calibration range shown in the
table. Record the increased O
2
value on the Combustion Calibration sheet.
Natural Gas Combustion Calibration Readings
Valve Position
Oxygen (O
2
) %
Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
60%
5% - 6%
<20 ppm
<100 ppm
45%
5% - 6%
<20 ppm
<100 ppm
30%
5% - 6%
<20 ppm
<100 ppm
18%
5% - 6%
<20 ppm
<100 ppm
29.
If the oxygen level at the 18% valve position is too high and the Blower voltage is at the
minimum value, you can adjust the idle screw (TAC valve) which is recessed in the top of
the Air/Fuel Valve (see Appendix G). Rotate the screw 1/2 turn clockwise (CW) to add fuel
and reduce the O
2
to the specified level. Recalibration MUST be performed again from
60% down to 18% after making a change to the idle screw (TAC valve).
30.
This completes the NATURAL GAS combustion calibration procedures.
4.4 PROPANE COMBUSTION CALIBRATION
Complete the instructions below if the unit will run on PROPANE gas rather than Natural Gas.
NOTE
When installed and operated in accordance with the requirements
specified in this section, this Benchmark boiler delivers low NOx
emissions of
<30 ppm
at all firing rates. Unlike units running on
Natural Gas, there is no ultra-low NOx emissions option.
The Benchmark 750/1000 boiler is combustion calibrated at the factory prior to shipping.
However, recalibration is necessary as part of initial start-up due to changes in the local altitude,
gas BTU content, gas supply piping and supply regulators. Combustion Calibration Test Data
sheets are shipped with each unit. These sheets must be filled out and returned to AERCO for
proper Warranty Validation.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
