4-5
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Ignition spark response test
This test should be carried out on any equipment that uses an ultraviolet flame
detector. The test is to check whether or not the ultraviolet flame detector responds
to UV rays emitted from the ignition spark.
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Ultraviolet Flame Detector
Carry out the following test to check whether or not the ultraviolet flame detector
or flame rod responds to the UV rays emitted from the ignition spark (so that the
FLAME LED lights up).
(1) Close the manual fuel valves of the pilot and main burner.
(2) Start operation, and measure the flame voltage during the pilot ignition
sequence to check for any influence from UV rays.
(3) If the FLAME LED lights up, carry out the following adjustment, referring also
to the equipment user’s manual.
• Move the position of the ultraviolet flame detector or ignition spark rod so
that the ultraviolet flame detector is not influenced by UV rays.
• Install a shield, for example, to prevent UV rays from the spark from
entering the optical path of the ultraviolet flame detector, and adjust so that
the influence of the spark on the flame voltage is 0.4Vdc or less.
Chapter 4. ADJUSTMENTS FOR TRIAL OPERATION
CAUTION
Make sure that the ultraviolet flame detector cannot detect UV rays emitted
by sources other than the burner. If the ultraviolet flame detector responds to
other UV sources, it will judge that there is a flame even if the burner flame is
out. As a result, fuel will continue to be supplied, causing a very serious
explosion hazard.
