Troubleshooting guide
INITIAL START-UP
23. If the oxygen level is not within the specified
range, adjust the level using the up (Λ) and
down (V) arrow keys on the VFD. Using the
up (Λ) arrow key will increase oxygen level
and the down (V) arrow key will decrease
the oxygen level.
24. Once the oxygen level is within the specified
range at 85%, lower the firing rate to 65%
and select VFD parameter 64. The oxygen
level at the 65% firing rate should be as
shown below.
Combustion Oxygen Level at
65% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
NOx
6.3 % <50 ppm <20 ppm
25. Adjust the oxygen level as necessary to
obtain the required reading at the 65% firing
rate.
26. Next, set the firing rate to 45% and select
VFD parameter 63. The oxygen level at the
45% firing rate should be as shown below.
Combustion Oxygen Level at
45% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
NOx
6.5 % <50 ppm <20 ppm
27. Adjust the oxygen level as necessary to
obtain the required reading at the 45% firing
rate.
28. Next, set the firing rate to 30% and select
VFD parameter 62. The oxygen level at the
30% firing rate should be as follows:
Combustion Oxygen Level at
30% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
NOx
5.6 % <50 ppm <20 ppm
29. Adjust the oxygen level as necessary to
obtain the required reading at the 30% firing
rate.
30. Finally, reduce the firing rate to 18% and
select VFD parameter 61. The oxygen level
at the 18% firing rate should be as shown in
the following tabular listing:
Combustion Oxygen Level at
18% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
NOx
6.5 % <50 ppm <20 ppm
31. Adjust the oxygen level as necessary to
obtain the required reading at the 18% firing
rate.
IMPORTANT
Repeat steps 20 through 31 until the VFD
does not require adjustment when
sequencing from 70% to 14%.
32. This completes the Natural Gas combustion
calibration procedures.
IMPORTANT
Refer to Appendix K for switchover
instructions when changing from Natural
Gas to Propane or from Propane to
Natural Gas.
4.4 PROPANE COMBUSTION
CALIBRATION
The Benchmark 3.0 Dual Fuel Boiler is
combustion calibrated at the factory prior to
shipping. Recalibration as part of initial start-up
is necessary due to changes in the local altitude,
gas BTU content, gas supply piping and supply
regulators. Factory 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.
1. Open the water supply and return valves to
the unit and ensure that the system pumps
are running.
2. Open the propane supply valve(s) 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 Fire
Rate message will be displayed with the
present rate in %. Also, the MANUAL LED
will light.
4-5