DIYbanter - View Single Post - Why the Fire in a Gas Boiler Extinguished By Itself?

wrote:
I would like to know what was the reason why the fire in a gas boiler
can be extinguished by itself. I have a relatively old boiler that
runs by natural gas to heat water for my baseboard heating units. A
couple days ago, somehow the fire in the boiler extinguished by itself
-- no fire, not even the pilot. The control switch was at the "ON"
position. But I didn't smell any gas. I can re-ignite the boiler
without any problem, and the problem has not returned; this is good.
But I would like to know why the fire in the boiler would be
extinguished in the first place.

I have the following specific questions:

- Would this happen when the natural gas supply was momentarily
running out of gas? But the fire in my relatively new water heater
was still burning while the fire in the boiler was extinguished. If
the natural gas supply was momentarily stopped, I would assume that
the fire in both the boiler and the water heater would be
extinguished, right?

- Is the boiler smart enough to automatically switch off the gas
supply when it senses that the fire is extinguished?

You bet! There should be a thermocouple (it looks like a closed metal
tube) sticking in the pilot flame. It senses the pilot and if it does not
sense a pilot flame or if the thermocouple fails it turns the gas off to
both the main burner and the pilot. They are cheap and easy to replace.
What you are observing is common when one is getting old. You can also try
cleaning it and or adjusting it to make sure it is in the hot part of the
flame. However they are cheap enough, most people just replace them.

I am asking this
because the control switch was at the "ON" position but I didn't smell
any gas.

- Will this happen when someone (like my 2-year-old child) toggles
the power switch of the boiler Off and On?

It could under some circumstances, but don't blame the little guy yet.

Thanks in advance for any info.

Jay Chan

--
Joseph Meehan

Dia duit