AERCO BMK 1.5 LN July 2011 - Manual (Page 63)

CHAPTER 6: SAFETY DEVICE TESTING
PR2: 05/09/12 Page 63 of 152
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
6. The unit should shut down and display a HIGH GAS PRESSURE fault message when the
gas pressure exceeds 4.7” W.C. The FAULT indicator should also start flashing.
7. Reduce the gas pressure back to 3.0” W.C.
8. Press the
CLEAR button on the Control Box to clear the fault.
9. The fault message should clear and the FAULT indicator should go off. The unit should
restart.
10. Upon test completion, close the ball valve and remove the manometer. Replace the
1/4“ plug removed in step 1.
6.4 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.
6.5 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.