AERCO BMK 6000 Dual Fuel - Manual (Page 62)

Benchmark 6000 DF Installation, Operation & Maintenance Manual
CHAPTER 4 – INITIAL START-UP
Page 62 of 219 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0096_0B
03/21/2014
Ph.: 800-526-0288
GF-141
4.3 PILOT IGNITION
The Benchmark 6000 is equipped with an interrupted pilot ignition system. The pilot is ignited by
a spark discharge within the Pilot Burner inside the combustion chamber. The input of the Pilot
flame is approximately 18,000 BTU/hr. The Pilot Burner flame will stay ignited until the main
Burner flame has stabilized and “Flame Proven” appears in the C-More Controller display.
A Pilot gas supply regulator reduces the supply pressure from line pressure to 4.9” W.C. An
orifice (0.073” dia.) further restricts the gas flow to the Pilot in accordance with UL safety test
requirements.
The Pilot Burner should be inspected at the beginning of each heating season, or every 6
months for continuous operation units. It is constructed of high quality, heat resistant stainless
steel materials, however some darkening of the metal is to be expected. No adjustment of the
Pilot should be required, however the gas pressure downstream of the regulator should be
checked if an ignition issue is encountered. Refer to Figure 4-1 for test port location.
The Pilot flame is proven by the AERCO BST Sensors located above and below the Pilot. The
boiler has two Pilot Flame Detectors. The AERCO BST is an optical sensor inserted in a
viewport. The sensor has a red LED which changes from flashing to steady- ON when the sensor
encounters the flicker of a flame that meets or exceeds the internal sensing threshold. The
sensor is inserted into a tube with a quartz window and observes the Pilot through a hole in the
refractory. The hole in the refractory should be checked annually to ensure that the optical path
to the Pilot Burner is clear.
NOTE
The AERCO BST sensor switches the signal to neutral when the flame is
proven.
NOTE
When installed and operated in accordance with the requirements specified
in this manual, the Benchmark 6000 delivers low NOx emissions of <20 ppm
at all firing rates; or if required <9ppm.
The procedures provided in section 4.4 and 4.5 are used to combustion
calibrate the Benchmark 6000 boiler.
4.4 NATURAL GAS COMBUSTION CALIBRATION
Refer to section 4.6 for instructions on how to switch the BMK 6000 boiler fuel source from
Natural Gas to Propane Gas.
NOTE
When installed and operated in accordance with the requirements specified
in this section, the Benchmark 6000 boiler delivers low NOx emissions of
<20 ppm at all firing rates. Alternatively, these boilers can be combustion
calibrated to provide ultra-low NOx emissions of <9 ppm.
To combustion calibrate the boiler to produce low NOx emissions of <20
ppm, complete the instructions in this section. To combustion calibrate the
boiler to produce ultra-low NOx emissions of <9 ppm (Natural Gas only)
first complete the instructions in this section and then, in addition, complete
the instructions in Appendix N.