mm wrote:
On 17 Jan 2007 13:22:47 -0800, "z" wrote:


wrote:
I have an oil-burning furnace, with an intermittent problem. Most of
the time when the temperature drops below the thermostat level, it
kicks in just fine. But every so often, with no particular regularity,
it fails to start. I have to go down to the basement and press the
manual restart button (which always works with just one push). I have
found no factor that seems to explain when it fails to automatically
start. (For example, it seems no worse on particularly cold days, or
damp day, etc.) It is just that once every day or so, it fails to come
on.

I have a service contract, and the furnace is old but has been
maintained. A couple service guys have been out to look at it, and
each has done a little something, but nothing has definitively solved
the problem. (I am embarrassed to admit here that I am NOT the
handyman type. I do not watch over their shoulders, and I do not know
precisely what they have tried.)

I have a guy coming out again in a couple days, and I am hoping to be a
little bit better armed with knowledge, and be more involved in the
diagnosis. I was wondering if anyone has ideas on what sorts of things
could cause this intermittent problem.

Thanks.

My old furnace, I kept the temp low because I didn't have cash to pay
for luxuries like heat, so that it came on seldom enough that it had
trouble priming itself or getting oil to the burner or whatever before

The same infrequency of starting would be the case if you had the
thermostat higher but it wasn't as cold out as it actually was.

That doesn't mean you're not right about it having trouble pumping the
oil.

the ignition gave up trying which shut down the pump, so I had to go
down and keep my finger on the little red button for a while, then it
was good for the rest of the cold snap.

A) Are we talking about a mechanical or electronic button/reset?

Probably electronic, although it was a slightly large button about the
size of the eraser on the end of a pencil which had a distinctly loose
and wiggly feel to it.

B) Isn't that symptom part of a different problem? I definitely
might be wrong about how it works, but I thought once you pushed the
reset button, the control energized the furnace for a certain time
period before it tripped again.

So doesn't that mean there is something wrong with the reset function
that you have to hold the button down longer than a second?

Maybe. IIRC, the first time I tried it, just pushing the button once
didn't make the furnace fire up, so my primitive half-frozen mind
determined to hold the damn button down until the furnace fired up or
blew up. Then I just stuck with what worked.


Or are you saying you held the button down for that entire time period
so you were still holding it when it was ready for a second reset?

My oil furnace used to have trouble in the control box restarting.
Sometimes iirc I could feel the relay vibrating, and I looked into
replacing the relay, couldn't find a matching relay that would fit,
and eventually the thing settled down, and it's been fine for 5 years
or more now.