Preparations for Startup
3-8
750-392
CBEX-DE
6. To make the final adjustment, slowly reduce the pilot gas pressure with the regulator until the flame can no
longer be seen through the sight tube. Then slowly open the cock until a flame providing full sight tube cover-
age is observed.
The adjustment must be accomplished within the time limit of the safety switch or approximately 30 seconds
after the detector is removed. If the control shuts down, manually reset it. Replace the detector and repeat the
process from step 5.
7. When a suitable flame as indicated in step 6 is obtained, replace the detector. Observe the reading on the DC
voltmeter. The reading should be between 2-1/4 and 5 micro amps when using a lead sulfide detector and a
standard amplifier. See the flame signal table in the manufacturer’s bulletin for values of other combinations.
The flame signal indicated on the annunciator type relay should not be less than 5 Vdc, and may be as high
as 20 VDC or greater.
The reading must be steady. If the reading fluctuates, recheck the adjustment. Be sure that the flame detector
is properly seated and that the lens is clean.
8. Return the Run/Test switch to the “Run” position.
9. If main flame has not been previously established, proceed to do so in accordance with instructions elsewhere
in the manual.
10. The reading of the main flame signal should also be checked. Observe the flame signal for pilot alone, pilot
and main burner flame together and the main burner flame at high, low, and intermediate firing rate positions.
Readings should be steady and in the range indicated in step 7.
3.8 — Gas Pressure and Flow Information
Because of variables in both the properties of gas and the supply system, it will be necessary to regulate the
pressure of the gas to a level that produces a steady, dependable flame that yields the highest combustion effi-
ciency at rated performance yet prevents over-firing. Once the optimum pressure has been established, it should
be recorded and periodic checks made to verify that the regulator is holding the pressure at this level. Occasional
modification in fuel composition or pressure by the supplier may, at times, require readjustment to return the
burner to peak efficiency. If the gas pressure regulator is furnished by others, instructions and adjusting proce-
dures recommended by the manufacturer should be followed.
Wear a protective shield or suitable glasses and keep eyes sufficiently away from the sight tube opening. Never
remove the flame detector while the main burner is firing. Failure to follow these instructions could result in serious
injury or death.
When checking the pilot flame, be aware the electrode is energized. Failure to follow these instructions could result in
serious injury or death.
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Warning
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Warning
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