Instruction Manual

Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 3 – OPERATION
Page 52 of 192 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0082_0J
05/21/2014 Ph.: 800-526-0288 GF-130
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 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. Current to the spark igniter
is monitored for proper level. If no spark is present, the Controller will stop the ignition
process at 3 seconds and shut down the boiler. Refer to Chapter 8 – Troubleshooting
for guidance if this occurs.
(c) The gas Safety Shut-Off Valve (SSOV) is energized (opened) allowing gas to flow
into the Air/Fuel Valve.
Figure 3-6: Air/Fuel Valve In Ignition Position
STEPPER MOTOR
TO
BLOWER
AIR
INLET
25
BLOWER PROOF
SWITCH
BLOCKED
INLET SWITCH