FYI,
If this is Lennox Conservator
'Mid-Efficency" furnace with the Electronic ignition lite pilot lite
and motorized Chimney damper there is a well known problem with the
electronic controls going on them, usually made by Johnson.

Most of the ones here installed about 19 - 20 years ago have either
been replaced, had the controls replaced or had the controls removed
and been converted to a pilot light and no damper configeration.

How do I know? I had a Lennox Conservator G8E model and found out by
speaking to both the gas company and several HVAC guys over the 4
years it took to completely give up the ghost. Lennox makes a retrofit
kit but I wasn't prepared to spend $500 to have it installed on a 20
yr old furnace.

This info may relate or not.

Canadaloon

BTW I had the flame sensor (Lennox part 12F1901, Sensor: Flame sensor
for penn valve) replaced 3 times in 4 years before it finally went.




I'm having a problem with my furnace that I hope someone can shed some
light on. The furnace will run and then usually get to the desired
temperature set by the T-stat and stop. Then when the T-stat thinks
it should run again the the T-stat will show that the furnace is
running (it's an electronic T-stat), but the furance will not kick on.
If I am near the furnace, I can only hear a real faint buzzing sound
(which goes away if I shut the power off to the furnace). If I either
turn the T-stat off and on a few times or turn the power to the
furnace off and then on, the furnace will usually kick on (until the
next go around).

It seems to be a furance issue and not a T-stat issue, but I'm looking
for some help. Unless it is something really easy to fix, I plan on
calling a repairman, but I would still like to be knowledgable of the
problem beforehand.

It is a forced air Lennox furnce about 18 years old. I will mention
too that it started doing this a couple of days ago soon after I used
the electrical outlet on the furnace to power a shop vac (I rarely use
this outlet -- and I don't know if this would be related anyway).

Thanks.

Jim