It's wasting gas and killing thermocouples. Finally decided to
research this after another thermocouple died today after only two or
three seasons. The boiler's manual shows a pilot flame profile but
unfortunately I'm unable to view the actual flame from the side so
I've adjusted the flame so that the thermocouple shows no signs of
glowing red but is obviously hot enough to maintain pilot gas flow.
Does this make sense? Thermocouple is centered properly and flame is
hitting it in the right place. I could tell based on where started to
glow first when lighting the pilot before it was adjusted.
On Sun, 14 Oct 2007 12:52:47 -0700, email@example.com wrote:
If it's hot enough to maintain the pilot that should be fine. I've
actually adjusted pilots using an adapter inline with the thermocouple
that gave me a test point to monitor the voltage the thermocouple produced.
There is a point where adding more flame makes no change in the voltage
and that's usually with a very minimal flame, just enough to surround the
Oh yeah, the main burners light as soon as the solenoid sounds, that
was always the case. Seems like the pilot would go out after the main
burners turned off and not when it kicked in as I had originally
thought. Anyway, it's working fine now after further adjustment. I
adjusted the pilot gas flow so that it took the specified one minute
to stay on when lit from cold. Thermocouple glows red now, however,
the flame is about half as intense as before. Going to replace the
pilot burner assembly as well, orifice may be degraded, it's 28 years
On Sun, 14 Oct 2007 19:39:04 -0700, firstname.lastname@example.org wrote:
Ooooooo 28 years old, you didn't mention that. I don't think it's abnormal
for the tip of a pilot to glow a bit. I guess I misunderstood you as to
when the pilot extinguished. When there is a situation where there is an
adjustable pilot, my training was to meter the thermocouple voltage output
in circuit. The adapters I used to do that also served useful in saving
time when there was a problem with the pilot. Took a minute to hook the
adapter up and measure millivolts versus 5 or more minutes to replace a
thermocouple only to realize that wasn't the problem.
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