Do fans slow down over time ?

[Hurricane]

I have a Quad 5100 insert and I feel like the fans are running slower than I remember. I know there is a speed control and it is on high. I am not sure if it would really be noticeable because the stove is 12 years old and if it slowed down over time I would not be able to tell. I do plan on testing the speed control but the stove is cranking right now and will be for many days ahead. No break in temp in forecast.
So I am just wondering if anyone has any experience with the fans loosing speed over time, and should I just replace them if the speed control tests OK.

 

[pen]

When was the last time the blower was cleaned? I am willing to bet it is slowing down and it's because there is 1/4 in worth of dust stuck to all the impeller or fan blades.

pen

 

[blades]

yes and no.. Bearings could be going dry causing undue friction. The fin/blades/squirel cage of the blower/fan could be loaded with caked on dust which would reduce the air flow, & cause an out of balance problem which would slow the rpms. Either of the above would cause the motor to draw higher amount of amperage which could cause issues with the speed control. Also the potentiometers ( speed control, variable resistor) due or can develop a bad spot in their range of adjustment. pull the blower and give it a cleaning as well as oiling the pads in side the bearing cups. ( you have to pull the motor apart to get at those on most of these blowers. The bearings are just oil impregnated bronze bushings and do dry out over time.

 

[begreen]

As bearings dry up, fans can and do slow down. Sleeve bearings will wear faster. If you can get lubricant to the bearing felt (oil wick) before too long, it can restore fan speed and add years to the fan's life. Sometimes there are oil cups or at least a port to the wick. But in other cases you need to drill a small hole. I try to oil fan motors that run regularly at least once every 2-3 years.

 

[Hurricane]

Thanks for the replies. I did clean the fans this year but have not oiled them.
The potentiometer may have a flat spot that is why I was looking to test it.

The fans are the box type that is installed in computers and electronic equipment and not the squirrel cage type. I will be taking out the fans and oiling them as soon as the weather lets me.

 

[begreen]

Pancake (muffin) axial fans are usually not serviceable other than cleaning. I suspect Quad chose a decent brand with ball bearings to ensure longevity.

 

[pgmr]

Pancake (muffin) axial fans are usually not serviceable other than cleaning. I suspect Quad chose a decent brand with ball bearings to ensure longevity.

Actually, most of these can be oiled by peeling back the label. One or two small drops is all it takes. I do this often on computer fans.

 

[begreen]

Great. Thanks for the tip! (Computers don't stay long enough here for me to oil their fans.)

 

[Hurricane]

I finally got a chance to do some testing with the fans. I was away for new years and the stove went out, so I took the opportunity to figure out what was wrong if anything. When I bypassed the potentiometer the fans took off like a jet engine and blew like never before. I took out the pot and there was a circuit board in the switch with the pot. I tried cleaning the pot with spray in electrical contact cleaner but it did not make much if any difference. I shopped around and ordered the new speed control and put it in today. The fans run at least twice as fast as before. The house is getting real warm and the fans are just above where they were running before.
It is pretty warm out right now at 30 degrees but the cold is coming back. I am wondering how much the faster fan will cool down the firebox ? Cannot test now unless I open the windows. Thanks for the pointers above.
I need to remove the fans to lube them because I cannot see how to lube them from the visible side. That is a longer project and will need to wait until I cool down the stove another day.