Watts Benchmark Aerco OMM-0122 - Page 66

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 66 of 122
NATURAL GAS Combustion Calibration Instructions
TABLE 4-3c: NATURAL GAS Final Valve Positions: 1500DF – 2000DF
Valve % Oxygen %
Nitrogen Oxide
(NO
x
)
Carbon Monoxide
(CO)
BMK 1500
Dual Fuel Units
70%
6.0% ± 0.2%
≤20 ppm
<100 ppm
50%
6.3% ± 0.2%
≤20 ppm
<100 ppm
40%
7.0% ± 0.2%
≤20 ppm
<50 ppm
30%
7.0% ± 0.2%
≤20 ppm
<50 ppm
16%
8.0% ± 0.2%
≤20 ppm
<50 ppm
BMK 2000 Dual Fuel Units
70%
6.5% ± 0.2%
≤20 ppm
<100 ppm
50%
6.5% ± 0.2%
≤20 ppm
<100 ppm
40%
6.5% ± 0.2%
≤20 ppm
<50 ppm
30%
6.5% ± 0.2%
≤20 ppm
<50 ppm
16%
5.5% ± 0.2%
≤20 ppm
<50 ppm
TABLE 4-3d: NATURAL GAS Final Valve Positions: BMK 2500 – 3000
Single Fuel
Dual Fuel
Nitrogen
Oxide (NO
x
)
Carbon
Monoxide (CO)
Valve % Oxygen % Valve % Oxygen %
BMK 2500
70%
5.9% ± 0.2%
70%
5.9% ± 0.2%
≤20 ppm
<100 ppm
50%
6.0% ± 0.2%
45%
6.2% ± 0.2%
≤20 ppm
<100 ppm
40%
6.3% ± 0.2%
30%
6.0% ± 0.2%
≤20 ppm
<50 ppm
30%
6.3% ± 0.2%
20%
5.8% ± 0.2%
≤20 ppm
<50 ppm
16%
6.0% ± 0.2%
16%
6.0% ± 0.2%
≤20 ppm
<50 ppm
BMK 3000
70%
5.1% ± 0.2%
85%
5.4% ± 0.2%
≤20 ppm
<100 ppm
50%
6.1% ± 0.2%
65%
5.5% ± 0.2%
≤20 ppm
<100 ppm
40%
5.0% ± 0.2%
45%
5.7% ± 0.2%
≤20 ppm
<50 ppm
30%
6.4% ± 0.2%
30%
5.6% ± 0.2%
≤20 ppm
<50 ppm
14%
6.4% ± 0.2%
14%
6.2% ± 0.2%
≤20 ppm
<50 ppm
NOTE:
If NO
x
readings exceed the target values in Table 4-3a through 4-3d, 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 lowest valve position (14%, 16% or 18%)
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 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 NATURAL GAS combustion calibration procedure.