MFC Series Boilers User Manual
CHAPTER 10 – MFC 8000/10000 DUAL FUEL BURNER
P
OMM-0104_94
AERCO International, Inc.
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100 Oritani Dr.
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Blauvelt, NY 10913
Page
111
of
170
GF-146
Ph.: 800-526-0288
12/29/2015
10.5 Pressure Variator
The pressure variator, shown in Figure 10-7 of the oil circuit makes, it possible to vary the
pressure on return of the nozzle depending on the flow rate required.
Governing of the pressure on return is obtained with the variation of a section by rotating the
servomotor 23) shown in Figure 10-1, which simultaneously also controls the gas butterfly valve.
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Pressure governor at 0° (maximum opening) = minimum pressure on nozzle return.
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Pressure governor at 90° (minimum opening) = maximum pressure on nozzle return.
The servomotor is operated by the electronic cam; by means of this device it is possible to set
different curves for oil and gas on the same servomotor (the air gate valve servomotor 4) shown
in Figure 10-1 may be operated in the same way.
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In adjusting with gas it is advisable to set the servomotor at 90° in order to reduce losses
from the gas butterfly valve.
In regulating with oil, setting is made depending on the type of nozzle used and on the
modulation required. Under the conditions of minimum firing rate, 20° rotation may be sufficient.
Figure 10-7: Hydraulic Gauges and Indicators
KEY to Figure 10-7
1 = Nozzle pressure gauge
2 = Position indicator (0 - 90) of pressure variator
