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 65 of 122
NATURAL GAS Combustion Calibration Instructions
26.
With the valve position at 100%, if the oxygen level is still not within the required tolerance
after adjusting the blower voltage, then 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 in 1/4-turn increments) Clockwise to reduce
O
2
level or counterclockwise to increase it. Allow the combustion analyzer to stabilize
following each adjustment.
27.
Once the oxygen level is within the specified range at 100%, record the O
2
, NO
x
and CO
readings on the Combustion Calibration Data Sheets provided with the unit.
28.
Press the Up ▲ arrow key until
SET Valve Position
appears and then press
CHANGE
.
29.
Use the Down ▼arrow key to lower the valve position to one of the following:
•
BMK 750 & 1000:
80%
•
BMK 1500 – 3000:
70%
NOTE:
Remaining combustion calibration steps are performed using the
Combustion Cal
menu in
the C-More Controller. The combustion calibration control functions will be used to adjust
the oxygen level (%) at valve position percentages described in the steps below. These
instructions assume that the
inlet air temperature is between 50°F and 100°F (10°C –
37.8°C)
. If NO
x
readings exceed the target values in Table 4-2, above, increase the O
2
level
up to 1% higher than the listed calibration range. Record the increased O
2
value on the
Combustion Calibration sheet.
30.
Repeat steps 21 through 25 for valve positions shown in Table 4-3a through 4-3d,
depending on the model you are calibrating. The O
2
, NO
x
and CO should stay within the
ranges shown in these tables.
TABLE 4-3a: NATURAL GAS Final Valve Positions: BMK 750 – 1000
Valve
Position
Standard NO
x
Ultra-Low NO
x
Carbon
Monoxide
(CO)
Oxygen (O
2
)
%
Nitrogen
Oxide (NO
x
)
Oxygen (O
2
) %
Nitrogen
Oxide (NO
x
)
80%
5.5% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<100 ppm
60%
5.5% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<100 ppm
45%
5.5% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<50 ppm
30%
5.5% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<50 ppm
18%
5.5% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<50 ppm
TABLE 4-3b: NATURAL GAS Final Valve Positions: BMK 1500 – 2000
1500 & 2000 – Single Fuel Units
Valve Position
Standard NOx
Ultra-Low NOx
CO
1500
2000
O
2
%
NOx
O
2
%
NOx
70%
6.0% ± 0.2%
≤20 ppm
5.5% ± 1.0%
≤9 ppm
<100 ppm
50%
6.3% ± 0.2%
≤20 ppm
5.8% ± 1.0%
≤9 ppm
<100 ppm
40%
7.0% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<50 ppm
30%
7.0% ± 0.2%
≤20 ppm
6.0% ± 1.0%
≤9 ppm
<50 ppm
16%
18%
7.0% ± 0.2%
≤20 ppm
8.0% ± 1.0%
≤9 ppm
<50 ppm
