Aerco BENCHMARK 6000 - Start;Stop Levels

Benchmark 6000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 3 – OPERATION
OMM-0086_0D AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 55 of 210
GF-133 Ph.: 800-526-0288 03/20/14
3.11 START/STOP LEVELS
The start and stop levels are the Air/Fuel Valve positions (% open) that start and stop the unit,
based on load. These levels are Factory preset as follows:
Start Level: 22%
Stop Level: 18%
Normally, these settings should not require adjustment.
Note that the energy input of the boiler is not linearly related to the Air/Fuel Valve position. Refer
to Table 3-8 and the chart in Figure 3-8 for the relationship between the energy input and
Air/Fuel Valve position for a BMK 6000 MBH boiler running on natural gas.
The boiler has a downstream low pressure gas switch that will shut down the boiler when the gas
pressure drops below 7” W.C. See Table 3-9.
Table 3-8: Relationship Between Air/Fuel Valve Position and Energy Input
For 6000 MBH Unit Running On Natural Gas
Air Fuel Valve Position
(% Full Open)
Boiler Energy Input
Turndown
Ratio
BTU/Hr
(% of Full
Capacity)
0%
0
0
0.0
10%
0
0
0.0
18% (Stop Level)
385,000
6
15.6
20%
400,000
7
15.0
30%
540,000
9
11.1
40%
770,000
13
7.8
50%
1,160,000
19
5.2
60%
1,650,000
28
3.6
70%
2,386,000
40
2.5
80%
3,515,000
59
1.7
90%
4,650,000
78
1.3
100%
6,000,000
100
1.0