AERCO BMK 1.5 LN Dual Fuel June 2010 - Manual (Page 41)

INITIAL START-UP
4-9
51. This completes the Propane Combustion
Calibration procedure.
FUEL
SELECTOR
SWITCH
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MOUNTING
PLATE
RESET BUTTON FOR
MANUAL RESET
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
FRONT VIEW
PROPANE NATURAL GAS OFF
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 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.
Figure 4-8
Over Temperature Limit Switch
Locations