11 start/stop levels – AERCO BMK 1000 User Manual
Page 53
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 3 – OPERATION
OMM-0082_0J
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Page 53 of 192
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Ph.: 800-526-0288
05/21/2014
6.
Up to 7 seconds will be allowed for ignition to be detected. The igniter relay will be turned
off one second after flame is detected.
7.
After 2 seconds of continuous flame, Flame Proven will be displayed and the flame
strength will be indicated. After 5 seconds, the current date and time will be displayed in
place of the flame strength.
8.
With the unit firing properly, it will be controlled by the temperature controller circuitry. The
boiler’s VALVE POSITION will be continuously displayed on the front panel bargraph.
Once the demand for heat has been satisfied, the Control Box will turn off the SSOV gas valve.
The blower relay will be deactivated and the Air/Fuel Valve will be closed. Standby will be
displayed.
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 for the relationship between the energy input and Air/Fuel Valve position for a BMK
750 MBH or BMK 1000 MBH boiler running on natural gas.
Table 3-8: Relationship Between Air/Fuel Valve Position and Energy Input
For 750 MBH & 1000 MBH Units Running On NATURAL GAS
Air/Fuel Valve
Position (% Open)
Energy Input
(BTU/Hr)
Boiler Energy Input
(% of Full Capacity)
750 MBH
1000 MBH
750 MBH
1000 MBH
0%
0
0
0
0
10%
0
0
0
0
18% (Stop Level)
50,000
50,000
6.7%
5%
20%
52,000
54,000
6.9%
5.4%
30%
108,000
140,000
14%
14%
40%
246,000
297,000
33%
30%
50%
369,000
443,000
49%
44%
60%
465,000
564,000
62%
56%
70%
554,000
660,000
74%
66%
80%
637,000
789,000
85%
79%
90%
733,000
933,000
98%
93%
100%
750,000
1,000,000
100%
100%