hvac blower motor intermittent
 

My house has a Friedrich brand furnace about 25 years old or so.
Sometimes I run the blower continuously (that is, not under control of
the thermostat) just to keep the air circulating in the house--neither
heating nor cooling active. Recently the blower motor has been cutting
out. The motor will just stop for several seconds and then restart
itself. Since this is probably not good for the motor, I have stopped
running the blower continuously.

Just wondering if there are is a typical cause for this. Do I need a
whole new blower or can I easily repair this motor by installing new
brushes or some such thing?

Thanks for any input.

"dog" wrote in message
...
My house has a Friedrich brand furnace about 25 years old or so.
Sometimes I run the blower continuously (that is, not under control of
the thermostat) just to keep the air circulating in the house--neither
heating nor cooling active. Recently the blower motor has been cutting
out. The motor will just stop for several seconds and then restart
itself. Since this is probably not good for the motor, I have stopped
running the blower continuously.

Just wondering if there are is a typical cause for this. Do I need a
whole new blower or can I easily repair this motor by installing new
brushes or some such thing?

Thanks for any input.

If the motor is stopping on its own, it sounds like it is shutting off due
to the thermal overloads inside the motor. This can be for a lot of
reasons. Replace the air filter, clean everything that you can before the
motor location.
Check to see that the motor has the cooling vents open and operational.
Failing all of this time for a new motor.

dog wrote:
Just wondering if there are is a typical cause for this. Do I need a
whole new blower or can I easily repair this motor by installing new
brushes or some such thing?

Bad run capacitor or high temperature cutout opening due to overload.

I doubt this caused by overheating - the internal overload wouldn't normally
reset that quickly. More like electrical problems in the motor. Fractional
horsepower motors aren't rebuilt, so you would replace it. However, with a
25 year old furnace, you should have the heat exchanger inspected - be
foolish to put that time and money into a furnce that needs to be replaced.
--
Scott McDaniel

"dog" wrote in message
...
My house has a Friedrich brand furnace about 25 years old or so. Sometimes
I run the blower continuously (that is, not under control of the
thermostat) just to keep the air circulating in the house--neither heating
nor cooling active. Recently the blower motor has been cutting out. The
motor will just stop for several seconds and then restart itself. Since
this is probably not good for the motor, I have stopped running the blower
continuously.

Just wondering if there are is a typical cause for this. Do I need a whole
new blower or can I easily repair this motor by installing new brushes or
some such thing?

Thanks for any input.

After checking the replies, I pulled the panel on the furnace to inspect
the motor area. Much to my surprise, the filter was more clogged than I
had expected. It seems it wasn't that long ago that I changed the filter
but I guess it was longer than that. Anyway, I installed a fresh filter,
turned on the blower, and it has not cut out since then. So I guess the
clogged filter was causing the motor to overheat. But I have been in
this house for 10 years and this has never happened to the motor before.
I've never exactly been religious about changing the filters but I've
always changed them several times a year. I guess this is my wake up
call from an aging system--better be more disciplined about changing
those filters. The A/C components are even older--somewhere between
25-40 yrs. Just trying to delay the inevitable...

thanks all

I normally tell my customers to check the filters at least once a month
and change them when they become dirty. Mine at home needs changed
every month.

Stretch

A clogged filter will take the load off the fan motor. This is
something that many people fail to understand.

wrote in message
ups.com...

A clogged filter will take the load off the fan motor. This is
something that many people fail to understand.


Load is off, RPMs increase, and without airflow, motor overheats..
basic stuff...

you are dead wrong on any residental type blower motor, a clogged
filter will reduce the load on a motor. If you have a overload
condition on a blower motor, and no other way to reduce the load, and
installing a damper and closing it till motor is not overloaded is
done, also the method to unload a circulator pump same thing.