Benchmark 2500 - 3000 Boilers
CHAPTER 3 – OPERATION
Page
48
of
204
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0094_0E
03/20/2014
Ph.: 800-526-0288
GF-137
c. The
VALVE POSITION
bargraph will show 100%.
Figure 3-4: Air/Fuel Valve In Purge Position
4.
Next, the blower proof switch on the Air/Fuel Valve (Figure 3-5) closes. The display will
show
Purging
and indicate the elapsed time of the purge cycle in seconds.
Figure 3-5: Blower Proof Switch
5.
Upon completion of the purge cycle, the Control Box initiates an ignition cycle and the
following events occur:
(a) The Air/Fuel Valve rotates to the low-fire (Ignition Position) 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.
STEPPER
MOTOR
TO BLOWER
AIR IN
PURGE
VALVE POSITION
DIAL AT 100%
AIR/FUEL VALVE
OUTLET TO BLOWER
BLOCKED
INLET
SWITCH
BLOWER
PROOF
SWITCH
AIR/FUEL VALVE
INLET FROM GAS
TRAIN