Was at Mom's house today and noticed that her furnace fan makes a kind of
vibrating/humming noise the first few seconds as it starts up. It's a Gas
furnace (Trane) and a 10 year old house.

Recently I had to replace the blower motor in my 22 year old Trane and
cleaned everything. When I start my fan, there's an initial buzzing from
the transformer and the fan comes on right away. The transformer buzzing
gets quieter after 2 seconds.

I know that blower motors may need oil from time to time, but then if it's
in need of lube, why does it make a noise only on start? After it gets
spinning I only hear air blowing.

The noise from Mom's sounds "wobbly", very much like a fan that isn't
aligned or attached right but then evens out from centrifugal force as the
rpm's increase.

Could the blower have come a bit loose from the frame or the frame from the
housing? I won't be back there for a few days but wanted to get some ideas
on what to look for if possible. Or could dust just be gumming up the works
and making the motor work harder. I'm not sure if it's ever been cleaned.

Also, the labored startup of the fan seems to last a little longer each
time, like whatever is going wrong is getting worse.

wall-e wrote:

Was at Mom's house today and noticed that her furnace fan makes a kind of
vibrating/humming noise the first few seconds as it starts up. It's a Gas
furnace (Trane) and a 10 year old house.

Recently I had to replace the blower motor in my 22 year old Trane and
cleaned everything. When I start my fan, there's an initial buzzing from
the transformer and the fan comes on right away. The transformer buzzing
gets quieter after 2 seconds.

I know that blower motors may need oil from time to time, but then if it's
in need of lube, why does it make a noise only on start? After it gets
spinning I only hear air blowing.

The noise from Mom's sounds "wobbly", very much like a fan that isn't
aligned or attached right but then evens out from centrifugal force as the
rpm's increase.

Could the blower have come a bit loose from the frame or the frame from the
housing? I won't be back there for a few days but wanted to get some ideas
on what to look for if possible. Or could dust just be gumming up the works
and making the motor work harder. I'm not sure if it's ever been cleaned.

Also, the labored startup of the fan seems to last a little longer each
time, like whatever is going wrong is getting worse.




Sometimes the motor capacitor will fail and cause the motor to labor on
startup.

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"CJT" wrote in message
...
wall-e wrote:

Was at Mom's house today and noticed that her furnace fan makes a kind
of
vibrating/humming noise the first few seconds as it starts up. It's a
Gas
furnace (Trane) and a 10 year old house.

Recently I had to replace the blower motor in my 22 year old Trane and
cleaned everything. When I start my fan, there's an initial buzzing
from
the transformer and the fan comes on right away. The transformer
buzzing
gets quieter after 2 seconds.

I know that blower motors may need oil from time to time, but then if
it's
in need of lube, why does it make a noise only on start? After it gets
spinning I only hear air blowing.

The noise from Mom's sounds "wobbly", very much like a fan that isn't
aligned or attached right but then evens out from centrifugal force as
the
rpm's increase.

Could the blower have come a bit loose from the frame or the frame from
the
housing? I won't be back there for a few days but wanted to get some
ideas
on what to look for if possible. Or could dust just be gumming up the
works
and making the motor work harder. I'm not sure if it's ever been
cleaned.

Also, the labored startup of the fan seems to last a little longer each
time, like whatever is going wrong is getting worse.




Sometimes the motor capacitor will fail and cause the motor to labor on
startup.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .


Thanks CJT, I didn't think about the capacitor.

On Tue, 22 Nov 2005 08:03:13 GMT, "wall-e" wrote:

The noise from Mom's sounds "wobbly", very much like a fan that isn't
aligned or attached right but then evens out from centrifugal force as the
rpm's increase.

Could the blower have come a bit loose from the frame or the frame from the
housing? I won't be back there for a few days but wanted to get some ideas
on what to look for if possible. Or could dust just be gumming up the works
and making the motor work harder. I'm not sure if it's ever been cleaned.


The blower and fan set up is as simple as one can get. Just
disassemble the motor and fan assemblies and do a thorough cleanup and
the furnace will be good for another ten years or so. The maintenance
stuff to look for will be the fan's axle and axle bearings. I had
overtightened my fanbelt before and this caused the shaft to wear into
the bearings and ovalled it. To correct the fan's startup and stop
"clunk noise" I tightened the fanbelt further. This of course caused
further wear. By the time I took the fan assembly apart the shaft had
worn down more than half its diameter, and the bearring holes
oversized. Should you replace the axle and bearings do not add any
lubrication. The bronze bearings are meant to run dry. Lube,
especially grease is commonly dried by the heat. This caused the
bearings to sieze.

PaPaPeng wrote:
On Tue, 22 Nov 2005 08:03:13 GMT, "wall-e" wrote:


The noise from Mom's sounds "wobbly", very much like a fan that isn't
aligned or attached right but then evens out from centrifugal force as the
rpm's increase.

Could the blower have come a bit loose from the frame or the frame from the
housing? I won't be back there for a few days but wanted to get some ideas
on what to look for if possible. Or could dust just be gumming up the works
and making the motor work harder. I'm not sure if it's ever been cleaned.



The blower and fan set up is as simple as one can get. Just
disassemble the motor and fan assemblies and do a thorough cleanup and
the furnace will be good for another ten years or so. The maintenance
stuff to look for will be the fan's axle and axle bearings. I had
overtightened my fanbelt before and this caused the shaft to wear into
the bearings and ovalled it. To correct the fan's startup and stop
"clunk noise" I tightened the fanbelt further. This of course caused
further wear. By the time I took the fan assembly apart the shaft had
worn down more than half its diameter, and the bearring holes
oversized. Should you replace the axle and bearings do not add any
lubrication. The bronze bearings are meant to run dry. Lube,
especially grease is commonly dried by the heat. This caused the
bearings to sieze.

That's simply incorrect. The bronze (sleeve bearings) are oilable. The
metal sleeve is microscopically perforated so that the oil in the wick
can seep through.

hvacrmedic

On Tue, 22 Nov 2005 07:20:49 -0600, RP
wrote:

That's simply incorrect. The bronze (sleeve bearings) are oilable. The
metal sleeve is microscopically perforated so that the oil in the wick
can seep through.


If the sleeves aren't sintered bronze, then are they lop-sided? ;-

--
-john
wide-open at throttle dot info