AERCO BMK 2.0 LN Natural Gas (SN G-11-1861 and above) - Manual (Page 62)

Chapter 4
Benchmark 2.0LN Low NOx Boiler
GF-123
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
Page 62 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
4.6 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.
4.7 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 4-6. 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 200°F. This switch will shut down and lock out the boiler if the water
temperature exceeds 200°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.