2.15.2.2
Igniter Timer
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NOTE: The spark duration adjustment extends the
life of the plug, transformer and other pilot
components.
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An igniter timer, with [manual] [automatic] adjustment of the spark
duration, shall be provided to set the time and duration of the igniter
spark during the ignition cycle, and to compensate for the distance of the
pilot gas supply from the oxidizer.
2.15.2.3
Pilot Timer
At the end of the purge, the pilot timer shall begin automatic ignition.
If the UV sensor fails to sense the pilot flame, the pilot solenoid valve
shall close, the pilot flame shall be extinguished, the system shall shut
down and the pilot fail alarm shall be activated.
2.15.2.4
Main Flame Timer
The main flame timer shall extend beyond the pilot timer cycle. When the
burner flame lights and the temperature exceeds the low temperature set
point on the temperature controller, the pilot flame shall be shut off.
The system shall shut down, and the main flame fail alarm shall be
activated, if the UV sensor fails to sense the pilot flame or the flame
temperature does not reach the low temperature set point by the end of the
main flame step.
2.15.3
Temperature Sensors, Transmitters and Controllers
2.15.3.1
Thermocouples
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NOTE: Narrow temperature ranges are more responsive
than broad ranges because the sensitivity is a
percentage of the range.
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Thermocouples shall conform to ISA MC96.1, Type K, suitable for continuous
operation and control at temperatures up to [50] [100] [150] [_____]
degrees C [80] [180] [260] [_____] degrees F above the temperature
specified in the performance requirements and accurate to 0.75 percent of
the maximum temperature. Each thermocouple used for control shall be
provided with high and low set points and an adjustable time delay before
initiation of each control action. A thermocouple located in or
immediately downstream of the combustion chamber shall control burner
operation and shall [indicate] [and] [record] combustion chamber
temperatures. [Three] [_____] additional thermocouple ports shall be
spaced at vertical intervals equal to the stack diameter, starting two
stack diameters from the top of the stack. Compensating lead wire
connecting the thermocouple to the read out shall be 16 gauge with a
weatherproof braid.
2.15.3.2
Thermometers
Thermometers shall conform to ASME PTC 19.3, with wells and temperature
SECTION 11378
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