Low Water Level Fault Test; Water Temperature Fault Test - Watts Aerco BENCHMARK 750 User Manual

Benchmark 750 – 1000 Boiler User Manual - INTERNATIONAL

6.4 LOW WATER LEVEL FAULT TEST

To simulate a low water level fault, proceed as follows:
1. Set the ON/OFF switch to the OFF position
2. Close the water shut-off valves in the supply and return piping to the unit.
3. Slowly open the drain valve on the rear of the unit. If necessary the unit's relief valve
may be opened to aid in draining.
4. Continue draining the unit until a LOW WATER LEVEL fault message is displayed and
the FAULT indicator flashes.
5. Place the unit in the MANUAL mode and raise the valve position above 30%.
6. Set the ON/OFF switch to the ON position. The READY light should remain off and the
unit should not start. If the unit does start, shut the unit off immediately and refer fault to
qualified service personnel.
7. Close the drain used in draining the unit.
8. Open the water shut-off valve in the return piping to the unit.
9. Open the water supply shut-off valve to the unit to refill.
10. After the shell is full, press the LOW WATER LEVEL RESET button to reset the low
water cutoff.
11. Press the CLEAR button to reset the FAULT LED and clear the displayed error
message.
12. Set the ON/OFF switch to the ON position. The unit is now ready for operation.

6.5 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 6-2.
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.
Page 74 of 170
11/03/2016
CHAPTER 6 – SAFETY DEVICE TESTING
Low Water Level Fault
Water Temperature Fault Test
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
OMM-0119_0A
GF-130-I