AERCO BMK 2000DF - Manual (Page 65)

Benchmark 1500DF - 2000DF Boilers
CHAPTER 4 – INITIAL START-UP
OMM-0098_0A AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 65 of 196
GF-144 Ph.: 800-526-0288 04/01/2014
Switchover from PROPANE to NATURAL GAS – Continued
15. Using the ▲ and ▼ arrow keys, scroll through the Configuration Menu and stop at Fuel
Type
.
16. Press the CHANGE key. Fuel Type will begin to flash.
17. Press the ▼ arrow key. Natural Gas will be displayed.
18. Press the ENTER key to store the Natural Gas Fuel type.
19. Replace the front door panel previously removed from the boiler.
20. This completes the steps necessary to switch from PROPANE Gas to NATURAL GAS.
4.6 REASSEMBLY
Once the combustion calibration adjustments are properly set, the unit can be reassembled for
service operation.
Reassembly
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 1/4” vent hole in the exhaust manifold.
Replace the 1/4” NPT plug in the manifold.
6. Replace all previously removed sheet metal enclosures on the unit.
7. This concludes reassembly of the unit after combustion calibration.
4.7 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 4-5. 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 4-5 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 4-5 and 4-6 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 section 4.5.1.