wrote in message
m...
"Stormin Mormon" wrote in message
...

From your descrip, it sounds like it might be a booster fan to move the
flue
gasses up the pipe. Sometimes those have an oil hole on each end of the
motor. Couple drops of SAE 20 or SAE 30 oil might quiet things down.

I couldn't really figure out what it was exactly. My motivation for
figuring things out is so that I can have a constructive brainstorm
with a gas contractor. This way I feel a little in control and would
prevent him from spending time and replace unnecessary parts.
CY: Yes, some contractors spend a long time throwing parts at it.


Not being a gas specialist, I only looked and reasoned, to the best of
my abilities, and I knew it had to be a 3rd moving part. Not the main
fan, not the blower, something else. The loud humming/buzzing was
coming from higher up I thought.

So, ok, in the middle of a snow storm, the furnace stopped working.
The gas guy took a while, but together, I was able to work through
things logically. He started to take things apart, and told me it
looks like the large main fan motor. I told him that when I put the
thermostat's switch fan position to 'on' instead of 'auto', the fan
sounds like it's moving air quite nicely. He measured the amperage
how much the motor was drawing, looked normal.

After he took the front of the furnace apart, and started the motor,
he now thought the motor was running well, and the noise was indeed
coming from elsewhere.

Then, bingo. Right outside the house there is a little box with
'power vent' written on it. It's built into a small metal cage, and
mounted on the outside of the house. In it, there is a motor that
sucks the air out, and assists in flowing the exhaust out. There is a
small solid line that runs inside to another small box with a sensor
in it. If the sensor says that the venting is working well, it tells
the furnace it's good to go.
The motor is stuck and is making a humming and buzzing kind of noise.
CY: Please remit $47.50 for diagnosis.


Needless to say, this box being outside results in a shorter lifespan
than if this fan had been inside just before the pipe exits the house.
By the looks of the manuals of Lennox, it looks like this suction
exhaust thingy (power vent thing) is optional, because the other fan
normally blows the air out of the furnace. The exhaust is on the side
of the house. The exhaust from furnace to outside is about 6 or 7
feet.

Now the fun part. This part is not in stock and needs to be ordered
from the manufacturer. The number is SWG-4HD. I have no idea what
this thing is going to cost me. If anyone could tell me, that would
help.
CY: I don't have that information. But I'm sure I could find out with a
couple phone calls.


Luckily, I have a gas fireplace, and it keeps half the house
relatively warm. The cat looks very comfortable, I think I might join
him ;-)
Tomorrow I'll find out more about this mistery part. Stay tuned.

Thanks to all giving me feedback btw. I'm not taking any chances and
will not risk blowing myself up, and am leaving the real work to a
professional ;-)
CY: You sound like an informed customer. Hacks hate you, and sincere folks
like you.