AERCO BMK 1.5 LN October 2012 - Manual (Page 43)

CHAPTER 3
OPERATION
PR1: 10/18//12 AERCO International Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288 Page 43 of 166
GF-120
OMM-0041 0E
Benchmark 1.5LN Low NOx Boiler
Installation, Operation and Maintenance Manual
Next, the blower proof switch on the Air/Fuel Valve (Figure 3-5) closes. The display will 4.
show Purging and indicate the elapsed time of the purge cycle in seconds.
Upon completion of the purge cycle, the Control Box initiates an ignition cycle and the 5.
following events occur:
a. The Air/Fuel Valve rotates to the low-fire ignition position and closes the ignition
switch. The dial on the Air/Fuel Valve (Figure 3-6) will read between 25 and 35 to
indicate that the valve is in the low-fire position.
b. The igniter relay is activated and provides ignition spark.
c. The gas Safety Shut-Off Valve (SSOV) is energized (opened) allowing gas to flow
into the Air/Fuel Valve.
100
DETAIL “A”
TO BLOWER
AIR IN
DIAL
(DETAIL “A”)
STEPPER
MOTOR
Figure 3-4: Air/Fuel Valve In Purge Position