Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 4 – INITIAL START-UP
Page
58
of
192
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0082_0J
05/21/2014
Ph.: 800-526-0288
GF-130
4.3 NATURAL GAS COMBUSTION CALIBRATION
Complete the instructions below if the unit will run on Natural Gas rather than PROPANE gas.
NOTE
When installed and operated in accordance with the requirements
specified in this section, this Benchmark 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
, first complete the instructions in this section
and then,
in addition
, complete the instructions in Appendix M.
The Benchmark 750/1000 boiler is combustion calibrated at the factory prior to shipping.
However, recalibration is necessary as part of initial start-up due to changes in the local altitude,
gas BTU content, gas supply piping and supply regulators. Combustion Calibration Test Data
sheets are shipped with each unit. These sheets must be filled out and returned to AERCO for
proper Warranty Validation.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
NATURAL GAS Combustion Calibration
1.
Open the water supply and return valves to the unit and ensure that the system pumps
are running.
2.
Open the natural gas supply valve to the unit.
3.
Set the control panel
ON/OFF
switch to the
OFF
position
4.
Turn on external ac power to the unit. The display will show loss of power and the time
and date.
5.
Set the unit to the manual mode by pressing the
AUTO/MAN
key. A flashing
manual
valve position
message will be displayed with the present position in %
.
Also, the
MANUAL
LED will light.
6.
Adjust the air/fuel valve position to
0%
by pressing the
▼ arrow key.
7.
Ensure that the leak detection ball valve downstream of the SSOV is open.
8.
Set
the
ON/OFF
switch
to
the
ON
position
.
9.
Change the valve position to
30%
using the ▲ arrow key. The unit should begin its start
sequence and fire.
10.
Next, verify that the gas pressure downstream of the SSOV is set to
2.0 ± 0.4” W.C.
If
gas pressure adjustment is required, remove the brass hex nut on the SSOV actuator to
access the gas pressure adjustment screw (Figure 4-3). Make gas pressure adjustments
using a flat-tip screwdriver to obtain a gas pressure
of 2.0” W.C. ± 0.4” W.C.
