3.7.5.1
Sequencing
The HTW generator shall [start,] operate, and stop in accordance with the
specified operating sequence.
3.7.5.2
Flame Safeguard
The operation of the flame safeguard control on oil- or gas-fired
generators shall be verified by simulated flame and ignition failures.
Burners having continuous or intermittent pilots shall be tested by
simulating main flame failure while the pilot is burning. The
trial-for-pilot ignition, trial-for-main-flame ignition, combustion control
reaction, and valve closing times shall be verified by stop watch.
a.
Immunity to Hot Refractory: The burner shall be operated at high
fire until the combustion chamber refractory reaches maximum
temperature. The main fuel valve shall then be closed manually.
The combustion safeguard shall drop out immediately causing the
safety shutoff valves to close within the specified control
reaction and valve closing times.
b.
Pilot Intensity Required: The fuel supply to the pilot flame
shall be gradually reduced 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,
the generator shall be rejected.
c.
Turndown Ratio: The specified turndown ratio shall be verified by
firing at the minimum firing rate.
d.
HTW Generator Limit and Fuel Safety Interlocks: Safety shutdown
shall be caused by simulating interlock actuating conditions for
each generator limit and fuel and safety interlock. Safety
shutdowns shall occur in the specified manner.
e.
Combustion Controls: The accuracy range and smoothness of
operation of the combustion controls shall be demonstrated by
varying the demand throughout the entire firing range required by
the turndown ratio specified for the [burner] [and] [stoker] and
in the case of automatic sequenced burners by further varying the
firing rate to require on-off cycling. The control accuracy shall
be as specified.
f.
Safety Valves: Safety valves on HTW generators shall not be
tested under operating conditions.
g.
Blowdown Valves and Try Cocks: Blowdown valves and try cocks
shall be tested for proper operation.
h.
Fans, Heaters, Pumps, and Motors: Draft fans, fuel oil heaters,
fuel pumps, and electric motors shall be tested when necessary to
determine compliance with the referenced standards. The operation
of fans, [fuel oil heaters] [stokers] [fuel pumps] and electric
motors shall be closely observed for possible defects or
nonconformance.
SECTION 15555A
Page 97
Previous Page
