AERCO BMK 2.0 LN Nat. Gas for Mass. only - Manual (Page 37)

INITIAL START-UP
4-5
Combustion Oxygen Level at
18% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide NOx
8.0 % <50 ppm <30 ppm
VFD
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MOUNTING
PLATE
RESET BUTTON FOR
MANUAL RESET
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
FRONT VIEW
LOGICSTICK
SLOT
29. Adjust the oxygen level as necessary to
obtain the required reading at the 18% firing
rate.
30. This completes the Natural Gas combustion
calibration procedures.
4.4 UNIT REASSEMBLY
Once the combustion calibration adjustments
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.
4.5 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 4-6. 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.
Figure 4-6
Over Temperature Limit Switch
Locations