AERCO BMK 1.5 LN Dual Fuel Jan 2009 - Manual (Page 37)

INITIAL START-UP
Combustion Oxygen Level at
60% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
5.0 % <50 ppm
22. Adjust the oxygen level as necessary to
obtain the required reading at the 60% firing
rate.
23. Next, set the firing rate to 45% and select
VFD parameter 68. 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
6.4 % <100 ppm
24. Adjust the oxygen level as necessary to
obtain the required reading at the 45% firing
rate.
25. Next, set the firing rate to 30% and select
VFD parameter 67. The oxygen level at the
30% firing rate should be as follows:
Combustion Oxygen Level at
30% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
6.7 % <100 ppm
26. Adjust the oxygen level as necessary to
obtain the required reading at the 30% firing
rate.
27. Finally, reduce the firing rate to 16% and
select VFD parameter 66. The oxygen level
at the 16% firing rate should be as shown in
the following tabular listing:
NOTE
At a 16% fire rate, if parameter 66 is
above 326, the VFD software will use 326
by default. 326 corresponds to a signal
output of 3.26 volts.
Combustion Oxygen Level at
16% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide
8.5 % <100 ppm
28. Adjust the oxygen level as necessary to
obtain the required reading at the 16% firing
rate.
29. This completes the Propane combustion
calibration procedures.
4.5 UNIT REASSEMBLY
Once the combustion calibration adjustments
are properly set, the unit can be reassembled for
service operation.
1. Set the ON/OFF switch ito the OFF position.
2. Disconnect AC power from the unit.
3. Shut off the gas supply to the unit.
4. Remove the manometer and barbed fittings
and reinstall the NPT plug using a suitable
pipe thread compound.
5. Remove the combustion analyzer probe
from the vent hole. Replace the NPT plug in
the vent hole using a suitable pipe joint
compound.
6. Replace the unit’s side panels and front
door.
4.6 OVER-TEMPERATURE LIMIT
SWITCHES
The unit contains both automatic and manual
reset over-temperature limit switches. These
switches are mounted on a plate next to the
VFD as shown in Figure 4-8. The switches can
be accessed by opening the front panel door of
the unit. The manual reset switch is not
adjustable and is permanently fixed at 210°F.
This switch will shut down and lock out the boiler
if the water temperature exceeds 210°F.
Following an over-temperature condition, it must
be manually reset by pressing the RESET
button before the boiler can be restarted. The
automatic reset over-temperature switch is
adjustable and allows the boiler to restart, once
the temperature drops below its temperature
setting. Set the automatic over-temperature
switch to the desired setting.
4-7