Benchmark 1500 - 2000 Boilers
CHAPTER 4 – INITIAL START-UP
OMM-0097_0E AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 63 of 182
GF-142 Ph.: 800-526-0288 10/01/2015
4.5 OVER-TEMPERATURE LIMIT SWITCHES
The unit contains three (3) types of over-temperature limit controls. These controls consist of a
Manual Reset button, a rotary adjustable Temperature Limit switch and a digital Over-
Temperature Alarm button. These controls are mounted on a plate as shown in Figure 4-5. They
can be accessed by opening the front panel door of the unit.
The Manual Reset button is not adjustable and is permanently fixed at 210°F (98.9°C). This
button will shut down and lock out the boiler if the water temperature exceeds 210°F (98.9°C).
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 adjustable Temperature Limit switch is manually adjustable from 32ºF - 212ºF (0ºC –
100ºC). This switch allows the boiler to restart, once the temperature drops below the selected
temperature setting on the dial. Set the dial on this switch to the desired setting.
The digital Over-Temperature Alarm switch shown in Figures 4-5 and 4-6 is preset at the factory
to 210ºF (98.9°C) 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 can be checked or adjusted using the procedure in section 4.5.1.
Figure 4-5: Over-Temperature Limit Switch Locations
4.5.1 Digital Alarm Switch Checks and Adjustments
The Over-Temperature Alarm switch settings can be checked or adjusted using the controls and
display on the front panel of the switch illustrated and described in Figure 4-6 and Table 4-8.
F
Alarm
RST
SET
Limit Control
Figure 4-6: Digital Over-Temperature Alarm Switch Front Panel
ALARM SWITCH
ADJUSTABLE TEMPERATURE
LIMIT SWITCH
TEMPERATURE LIMIT SWITCH
SWITCH
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