3.2.4
Operational Test
Continuously test the boiler(s) continuously under varying load conditions
to demonstrate proper operability of the combustion control, flame
safeguard control, programming control, and safety interlocks.Conduct this
test after the adjustment of the combustion controls has been completed
under the combustion test. The operational test shall continue for a
period of at least [8] [_____] hours and shall include the following:
3.2.4.1
Sequencing
The boiler shall start, operate, and stop in strict accordance with the
specified operational sequence.
3.2.4.2
Flame Safeguard
Verify the operation of the flame safeguard controls by simulated flame and
ignition failures. Test burners having intermittent pilots by simulating
main flame failure while the pilot is burning. Verify the trial-for-pilot
ignition, trial-for-main flame ignition, combustion control reaction, and
valve closing times by stop watch.
3.2.4.3
Immunity to Hot Refractory
Operate the burner at high fire until the combustion chamber refractory
reaches maximum temperature. The main fuel valve shall then be closed
manually. The flame sensing safeguard device shall immediately cause the
safety shutoff valves to close within the specified control reaction and
valve closing times. This test ensures that the flame sensing device will
not send a "false positive" signal from glowing refractory.
3.2.4.4
Pilot Intensity Required
Gradually reduce the fuel supply to the pilot flame to the point where the
combustion safeguard begins to drop out (sense "no flame") but holds in
until the main fuel valve opens. At this point of reduced pilot fuel
supply, the pilot flame shall be capable of safely igniting the main
burner. If the main fuel valve can be opened on a pilot flame of
insufficient intensity to safely light the main flame, readjustment of the
flame sensing device is required.
3.2.4.5
Boiler Limit and Fuel Safety Interlocks
Safety shutdown shall be caused by simulating interlock actuating
conditions for high and low temperature, high and low steam pressure, high
and low drum level, low feedwater, and fuel safety interlock. Safety
shutdowns shall occur in the specified manner.
3.2.4.6
Combustion Controls
Demonstrate the accuracy, range, and smoothness of operation of the
combustion controls by varying the steam demand through the entire firing
range required by the turndown ratio specified for the burner and in case
of automatic recycling burners, by further varying the firing rate to
require "on-off" cycling. Control accuracy shall be as specified.
SECTION 15517N
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