Watts Benchmark Aerco OMM-0122 - 5.5 WATER TEMPERATURE FAULT TEST

Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 5 – SAFETY DEVICE TESTING
OMM-0121_D • GF-205 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 87 of 122
5.5 WATER TEMPERATURE FAULT TEST
A high water temperature fault is simulated by adjusting the automatic Over-Temperature
switch. This switch is accessible from the front of the unit as shown in Figure 5-5a and 5-5b.
Water Temperature Fault Test Instructions
1. Start the unit in the normal operating mode. Allow the unit to stabilize at its setpoint.
2. Lower the adjustable Over-Temperature switch setting to match the displayed OUTLET
TEMPERATURE.
3. Once the adjustable Over-Temperature switch setting is approximately at, or just below,
the actual outlet water temperature, the unit should shut down. The FAULT indicator
should start flashing and a HIGH WATER TEMP SWITCH OPEN fault message should be
displayed. It should not be possible to restart the unit.
4. Reset the adjustable Over-Temperature switch to its original setting.
5.
The unit should start once the adjustable Temperature Limit switch setting is above the
actual outlet water temperature.
Figure 5-5a: Temperature Limit Switch Location – BMK 1500-3000
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MANUAL
SWITCH
RESET
BUTTON
OVER
TEMPERATURE
LIMIT DIGITAL
CONTROLLER
MANUAL
TEMPERATURE
LIMIT SWITCH