AERCO BMK 3.0 LN Dual-Fuel Series Gas Fired Low NOx Boiler System - Manual (Page 51)

SAFETY DEVICE TESTING
6-3
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 left side 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.
6. 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.
7. Reset the adjustable over-temperature
switch to its original setting.
8. The unit should start once the adjustable
temperature limit switch setting is above the
actual outlet water temperature.
RESET BUTTON FOR MANUAL
RESET TEMPERATURE LIMIT
SWITCH
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MOUNTING
PLATE
ON SHELL
HIGH LIMIT
Figure 6-2
Temperature Limit Switch Setting