specified elsewhere.
3.2.6.2
Steady State Combustion Tests
Test fuel burning and combustion control equipment with each of the
specific fuels at the minimum limit of the turndown range and at increments
of 50, 75 and 100 percent of full rated load. Each test run shall be at
least two hours on each fuel and until stack temperatures are constant and
capacity and efficiency requirements of this specification have been
verified and recorded. Verify proper operation of instrumentation and
gages during the tests.
3.2.6.3
Varying Load Combustion Tests
Test boilers continuously under varying load conditions to demonstrate
proper operability of the combustion control, flame safeguard control,
programming control and safety interlocks. Conduct these tests after
adjustment of combustion controls has been completed under the steady state
combustion tests. Continue variable load operational tests for a period of
at least 8 hours.
a.
Sequencing: Boiler shall start, operate and stop in strict
accordance with the specified operating sequence.
b.
Flame Safeguard: Verify operation of flame safeguard controls by
simulated flame and ignition failures. Verify trial-for-pilot
ignition, trial-for-main flame ignition, combustion control
reaction and valve closing times by stop watch.
c.
Immunity to Hot Refractory: Operate burner at high fire until
combustion chamber refractory reaches maximum temperature. Main
fuel valve shall then be closed manually. Combustion safeguard
shall drop out immediately causing safety shutoff valves to close
within the specified control reaction and valve closing times.
d.
Pilot Intensity Required: Gradually reduce fuel supply to the
pilot flame to the point where the combustion safeguard begins to
drop out (sense "no flame") but holds in until main fuel valve
opens. At this point of reduced pilot fuel supply, the pilot
flame shall be capable of safely igniting the main burner. When
the main fuel valve can be opened on a pilot flame of insufficient
intensity to safely light the main flame, the boiler shall be
rejected.
e.
Boiler Limit and Fuel Safety Interlocks: Safety shutdown shall be
caused by simulating interlock actuating conditions for each
boiler limit and fuel safety interlock. Safety shutdowns shall
occur in the specified manner.
f.
Combustion Controls: Demonstrate accuracy, range and smoothness
of operation of the combustion controls by varying steam demand
through entire firing range required by turndown ratio specified
for the burner. Control accuracy shall be as specified.
g.
Safety Valves: High pressure limit switch shall be locked out or
otherwise made inoperative and the boiler safety valves shall be
lifted by steam. Determine the relieving capacity, popping
pressure, blowdown and reseating pressure by observation and
measurement in accordance with the ASME BPVC SEC I. The ASME
SECTION 15502N
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