Watts Benchmark Aerco OMM-0122 - Page 68

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 68 of 122
PROPANE Combustion Calibration Instructions
16. Press the Down▼ arrow key until SET Valve Position appears on the display, then press
CHANGE.
17. Press the Up ▲ arrow key until the SET Valve Position reads 100%, then press ENTER.
18. With the valve position at 100%, insert the combustion analyzer probe
into the exhaust
manifold probe opening (see Figure 4-2a or 4-2b in Section 4.2.3) and allow enough time
for the combustion analyzer reading to stabilize.
19. Compare the combustion analyzer’s oxygen readings to the O
2
Sensor value displayed in
the Operating menu on the C-More Controller. The offset value in the Calibration menu can
be adjusted by ±3% to make the on-board O
2
sensor match the value from the combustion
analyzer. If the values differ by more than ±3% and your combustion analyzer is correctly
calibrated, the on-board O
2
sensor may be defective and need to be replaced
20. Compare the measured oxygen level to the oxygen range shown in Table 4-5. Also, ensure
that the nitrogen oxide (NO
x
) and carbon monoxide (CO) readings do not exceed the
values shown in Table 4-5. If you are not in a “NO
x
-limited” area and/or do not have a NO
x
measurement in your analyzer, set the oxygen (O
2
) at 5.5% ± 0.5%.
TABLE 4-5: PROPANE Calibration Readings at 100% Valve Position
Model Oxygen (O
2
) % Nitrogen Oxide (NO
x
) Carbon Monoxide (CO)
750 & 1000
5.5% ± 0.5%
≤100 ppm
<150 ppm
1500/2000
4.5% ± 0.5%
≤100 ppm
<150 ppm
2500
5.0% ± 0.4%
≤100 ppm
<150 ppm
3000
5.2% ± 0.4%
≤100 ppm
<150 ppm
21. Next, press the Down ▼ arrow key until CAL Voltage 100% is displayed.
22. Press the CHANGE key and observe that CAL Voltage 100% is flashing.
23. The oxygen level at the 100% valve position should be as shown in Table 4-5. Also, ensure
that the NO
x
and CO readings do not exceed the values shown in Table 4-5.
24. 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 mot
or as indicated on the
display. Pressing the Up ▲ arrow key increases the oxygen level and pressing the down
▼ arrow key decreases the oxygen level.
25. Once the oxygen level is within the specified range at 100%, press the ENTER key to store
the selected blower output voltage for the 100% valve position. Record all readings on the
Combustion Calibration Sheets provided.
26. With the unit running at 100% valve position, if the oxygen level is still
not within the
required tolerance af
ter 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.