Watts Benchmark Aerco OMM-0122 - Page 70

Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 4 – INITIAL START-UP
OMM-0121_D • GF-205 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 70 of 122
PROPANE Combustion Calibration Instructions
Valve Position Oxygen (O
2
) % Nitrogen oxide (NO
x
) Carbon Monoxide (CO)
BMK 3000
85%
5.2% ± 0.2%
≤100 ppm
<150 ppm
65%
5.4% ± 0.2%
<100 ppm
<150 ppm
45%
6.0% ± 0.2%
<100 ppm
<150 ppm
30%
6.4% ± 0.2%
<100 ppm
<100 ppm
18%
6.4% ± 0.2%
<100 ppm
<100 ppm
* NOTE:
Set the Valve Position at 18% but make adjustments to the Combustion Calibration value
designated as 16%.
NOTE:
If NO
x
readings exceed the target values in Table 4-6, 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.
31. 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 TAC screw, which is recessed in the top of the Air/Fuel
Valve (see Figure 4-4). Rotate the TAC 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 the lowest valve position after making a change to the TAC screw.
This completes the PROPANE gas combustion calibration procedure.