AERCO BMK 3.0 LN Nat. Gas APRIL 2009 - Manual (Page 45)

SAFETY DEVICE TESTING
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 Benchmark
3.0LN 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 460, 220,
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 LOW GAS PRESSURE FAULT TEST
Refer to Figure 6-1 and ensure that the leak
detection ball valve located at the high gas
pressure switch is closed.
1. Remove the 1/8 “ plug from the ball valve at
the low gas pressure switch shown in the
lower portion of Figure 6-1.
2. Install a 0 – 16 “ W.C. manometer or a W.C.
gauge where the 1/8" plug was removed.
3. Slowly open the ball valve near the low gas
pressure switch.
4. Place the unit in Manual Mode and adjust
the firing rate between 25 and 30%.
5. While the unit is firing, slowly close the
external manual gas shut-off valve.
6. The unit should shut down and display a
LOW GAS PRESSURE fault message at
approximately 2.6” W.C. The FAULT indi-
cator should also start flashing.
Figure 6-1
Low & High Gas Pressure Testing
7. Fully open the external manual gas shut-off
valve and press the CLEAR button on the
Control Box.
8. The fault message should clear and the
FAULT indicator should go off. The unit
should restart.
9. Upon test completion, close the ball valve
and remove the manometer. Replace the
1/8 “ plug removed in step 1.
6-1