AERCO BMK 2.0 LN Dual Fuel Nov 2010 - Manual (Page 43)

INITIAL START-UP
4-9
52. Press the CHANGE key. SET Valve Position
will begin to flash.
53. Press the ▼ arrow key until the SET Valve
Position reads 21%, then press the ENTER
key.
54. Press the ▼ arrow key until CAL Voltage
21% is displayed.
55. Press the CHANGE key. CAL Voltage 21%
will begin to flash.
56. The oxygen level at the 21% valve position
should be as shown below. Also, ensure that
the carbon monoxide (CO) and nitrogen
oxide (NOx) readings do not exceed the
values shown.
Combustion Oxygen Level at
21% Valve Position
Oxygen %
± 0.2
Carbon
Monoxide NOx
8.9 % <100 ppm <100 ppm
57. If the oxygen level is not within the specified
range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output
voltage to the blower motor as indicated on
the display. Pressing the ▲ arrow key
increases the oxygen level and pressing the
▼ arrow key decreases the oxygen level.
58. Once the oxygen level is within the specified
range at 21%, press the ENTER key to store
the selected blower output voltage for the
21% valve position.
59. This completes the Propane Combustion
Calibration procedure.
4.5 UNIT REASSEMBLY
Once the combustion calibration adjustments in
paragraph 4.3 (natural gas) and 4.4 (propane)
are properly set, the unit can be reassembled for
service operation.
1. Set the ON/OFF switch in 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 bracket located
behind the front door of the unit as shown in
Figure 4-3 (page 4-3). 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 temperature
setting.