CHAPTER 6: SAFETY DEVICE TESTING
Page
66
of
158
PR2: 04/22/13
Benchmark 2.0LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
OMM-0052_0E
GF-127
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
•
Ph: 800-526-0288
6.6 LOW WATER LEVEL FAULT TEST
To simulate a low water level fault:
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 and pressure relief valve 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.
6.7 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.
