AERCO BMK 3.0 LN Dual Fuel July 2011 - Manual (Page 41)

INITIAL START-UP
4-9
47. Press the ▼ arrow key until CAL Voltage
18% is displayed.
48. Press the CHANGE key. CAL Voltage 18%
will begin to flash.
49. The oxygen level at the 18% 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
18% Valve Position
Oxygen %
± 0.2
Carbon
Monoxide NOx
5.5 % <100 ppm <100 ppm
50. 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.
51. Once the oxygen level is within the specified
range at 18%, press the ENTER key to store
the selected blower output voltage for the
16% valve position.
52. This completes the Propane Combustion
Calibration procedure.
4.5 UNIT REASSEMBLY
Once the combustion calibration adjustments
are properly set for Natural Gas and Propane,
the unit can be reassembled for service
operation.
1. Access the Control Panel Configuration
Menu and ensure that the Max Valve
Position is set to the desired level for the
fuel being used for service operation (100%
for Natural Gas; 75% for Propane).
2. Set the control panel ON/OFF switch to the
OFF position.
3. Disconnect AC power from the unit.
4. Shut off the gas supply to the unit.
5. Set the Fuel Selector Switch to the
corresponding position for the fuel being
used for service operation.
6. Remove the manometer and barbed fittings
and reinstall the NPT plug using a suitable
pipe thread compound.
7. Remove the combustion analyzer probe
from the vent hole. Replace the NPT plug in
the vent hole using a suitable pipe joint
compound.
8. Replace the unit’s side panels and front
door.
4.6 OVER-TEMPERATURE LIMIT
SWITCHES
The unit contains three (3) types of over-
temperature limit switches. These switches
consist of a manual reset switch, a rotary dial
adjustable switch and a digital alarm switch.
These switches are mounted on a plate as
shown in Figure 4-7. 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 manual reset button shown in
Figurer 4-7 before the boiler can be restarted.
The rotary dial over-temperature switch is
manually adjustable from xxx to yyy ºF. This
switch allows the boiler to restart, once the
temperature drops below the selected
temperature setting on the dial. Set the dial on
this over-temperature switch to the desired
setting.
The digital alarm switch shown in Figures 4-7
and 4-8 is preset at the factory to 210ºF and
should not be changed. If an over-temperature
condition is detected, this switch automatically
shuts down the boiler and sounds an audible
alarm. If desired, the over-temperature alarm
switch settings can be checked or adjusted
using the procedure in paragraph 4.6.1.