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.

wrote:
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.

Hi,
Some gas valves have a screw for adjusting pilot flame size.

On Oct 14, 4:57 pm, Tony Hwang wrote:

Hi,
Some gas valves have a screw for adjusting pilot flame size.

I know, already adjusted flame.

On Oct 14, 5:05 pm, Meat Plow 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
thermocouple.

Unfortunately, what's happening now is that the pilot is fine until
the main burner kicks in then it dies. I'll increase the flow until
all is well on both fronts. Trial and error I guess.

On Oct 14, 6:05 pm, Meat Plow wrote:

Make sure your flue is clear and that the burner(s) light without delay.
You might be getting a puff while they light that puts a smaller pilot
flame out.

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
old.