11 start/stop levels – AERCO BMK 6000 Dual Fuel User Manual
Page 55
Benchmark 6000 DF Installation, Operation & Maintenance Manual
CHAPTER 3 – OPERATION
OMM-0096_0B
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Page 55 of 219
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Ph.: 800-526-0288
03/21/2014
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. They are as follows:
Natural Gas Start Level: 22%
Natural Gas Stop Level: 18%
Propane Gas Start Level: 22%
Propane Gas 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 Tables 3-8 & 3-9 and the chart in Figure 3-8 for the relationship between the energy input and
Air/Fuel Valve position for a Benchmark 6000 boiler running on natural gas.
Table 3-8: Relationship Between Air/Fuel Valve Position and Energy Input
For 6000 MBH Units Running Natural Gas or Propane
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%
588,000
10
10.2
40%
869,000
14
6.9
50%
1,283,000
21
4.7
60%
1,918,000
32
3.1
70%
2,590,000
43
2.3
80%
3,945,000
66
1.5
90%
5,185,000
86
1.2
100%
6,000,000
100
1.0
Table 3-9: Gas Pressure De-Rating Char for Natural Gas
Gas Pressure @
SSOV (inches W.C.)
Energy Input
Oxygen
DeRating
Inlet
Outlet
(BTU/hr)
(%O2)
(% Full Fire)
56
8
6,000,000
5.40
0%
14
8
6,000,000
5.40
0%
13
8
5,860,000
5.45
2%
12
7.95
5,860,000
5.41
2%
11.5
7.5
5,740,000
5.77
4%
11
7.1
5,610,000
6.17
6%
Note, there is no de-rating for Propane.