On Sun, 22 Dec 2013 00:05:22 -0500, "Robert Green"
wrote:

"micky" wrote in message

stuff snipped

How come the transformer failed at the same time I replaced the
nozzle? And the answer is almost obvious, even if it took me 2 days
to think of it. For the last several years, the furnace has probably
never run more than 20 minutes at a time, because I turn it on in the
fall when it's cold but not that cold out, and from then on the house
is 68 or 70.

Sounds like a candidate for an aux. muffin fan. I mount them on most
anything that runs very like stereos, dvr's, large-capacity battery chargers
or anything similar. It seems to have extended the life of a few pieces of
equipment that before fan cooling experienced capacitor failures and other
maladies on an all-too-regular basis.

Not a bad idea.

If you know that your transformer overheats when running too long and that's
happened more than once, it needs some sort of cooling mechanism - perhaps
even the old heat sink from a PC CPU.

Not a bad idea.

I don't have a feel for how much heat the CPU makes, or how much heat
the fan or the heat sink would remove. Maybe if I hold my hand in the
air stream from the CPU (this one has a shroud and all the air comes
out one place) I'll get a feel.

But I've changed the transformer now so until this one starts giving
the same problem, I'll probably not be able to test your idea.