AERCO BMK 1.5 LN Dual Fuel Feb 2013 - Manual (Page 67)

PR2: 05/01/11 Page 67 of 162
Benchmark 1.5LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0C
GF-121
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 6: SAFETY DEVICE TESTING
6.1 TESTING OF SAFETY DEVICES
Periodic safety device testing is required to ensure that the control system and safety
devices are operating properly. The boiler control system comprehensively monitors all
combustion-related safety devices before, during and after the start sequence. The
following tests check to ensure that the system is operating as designed.
Operating controls and safety devices should be tested on a regular basis or following
service or replacement. All testing must conform to local codes such as ASME CSD-1.
NOTE
MANUAL and AUTO modes of operation are required to
perform the following tests. For a complete explanation
of these modes, see Chapter 3.
NOTE
It will be necessary to remove the front door and side
panels from the unit to perform the following tests.
WARNING
ELECTRICAL VOLTAGES IN THIS SYSTEM MAY INCLUDE 120
AND 24 VOLTS AC. POWER MUST BE REMOVED PRIOR TO
PERFORMING WIRE REMOVAL OR OTHER TEST
PROCEDURES THAT CAN RESULT IN ELECTRICAL SHOCK.
6.2 NATURAL GAS LOW GAS PRESSURE FAULT TEST
Refer to Figure 6-1a and ensure that the leak detection ball valve located at the high gas
pressure switch is closed.
1. Ensure that the Fuel Selector Switch (Figure 4-3) is set to the NATURAL GAS
position.
2. Remove the 1/4“ plug from the ball valve at the low gas pressure switch shown in the
lower portion of Figure 6-1a.
3. Install a 0 – 16 “ W.C. manometer or a W.C. gauge where the 1/4" plug was removed.
4. Slowly open the ball valve near the NATURAL GAS low gas pressure switch.
5. Place the unit in Manual Mode and adjust the air/fuel valve position (% open) between
25% and 30%.
6. While the unit is firing, slowly close the external manual gas shut-off valve.
7. The unit should shut down and display a LOW GAS PRESSURE fault message at
approximately 1.0” W.C. The FAULT indicator should also start flashing.
8. Fully open the external manual gas shut-off valve and press the CLEAR button on the
Control Box.
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 2.