Benchmark 2500 - 3000 Boilers
CHAPTER 4 – INITIAL START-UP
Page
58
of
207
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0094_0F
09/30/2015
Ph.: 800-526-0288
GF-137
BMK 2500 Natural Gas Combustion Calibration
–
Continued
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 4-4). 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.
17. Lower the valve position to
70%
using the ▼arrow key.
NOTE
The remaining combustion calibration steps are performed using
the
Combustion Cal
menu
included in the C-More Control System.
The combustion calibration control functions will be used to adjust
the oxygen level (%) at valve positions of 70%, 50%, 40%, 30%
and 16% as described in the following steps. These steps assume
that the
inlet air temperature is within the range of 50°F to
100°F (10.0°C to 37.8°C)
. If NOx readings exceed the target
values shown, 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.
18. Press the
MENU
key on the front panel of the C-More and access the
Setup
menu. Enter
password
6817
and then press the
ENTER
key.
19. Press the
MENU
key on the front panel of the C-More until
Combustion Cal
menu
appears on the display.
20.
Press the ▲ arrow key until
SET Valve Position
appears on the display.
21. Press the
CHANGE
key.
SET Valve Position
will begin to flash.
22.
Press the ▲ arrow key until the
SET Valve Position
reads
70%
. Press the
ENTER
key.
23.
Next, press the down (▼) arrow key until
CAL Voltage 70%
is displayed.
24. Press the
CHANGE
key and observe that
CAL Voltage 70%
is flashing.
25. The oxygen level at the 70% valve position should be as shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the
following values:
Table 4-3:
Combustion Calibration Readings – 70% valve Position
Valve Position
Oxygen (O
2
) %
Nitrogen Oxide (NOx)
Carbon Monoxide (CO)
70%
5.9% ± 0.5%
≤20 ppm
<100 ppm
26.
If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the down ▼
arrow key decreases the oxygen level.
27. Once the oxygen level is within the specified range at 70%, press the
ENTER
key to
store the selected blower output voltage for the 70% valve position. Record all readings
on the Combustion Calibration Sheets provided.
