# Noisy Fan Blower during start up



## how (Feb 26, 2011)

The age, style, brand & model of the furnace would help. Failing capaciter, motor, fan bearings, belt/pulley set up are some possibilities depending on your furnace.


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## HVACDave (Oct 16, 2007)

Could just be the dirt in the cups of the fan cage are throwing it out of balance till it gets up to speed (could sound like a ticking noise that speeds up with the fan, or a intermittent scraping sound). Could be the capacitor (generally makes a growling noise on start up). Could be the bearings (generally a dry squealing noise). 

Do any of these fit? 

Could be the center supports of the cage itself are loose which will make it rattle (but that generally lasts all the time it is turning at higher speeds).


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## shabtay (Mar 16, 2011)

*Thanks HVACDave*

Hi HVACDave,

Thanks a lot for your response. Yes, I do think it could be the capacitor since it does make a growling noise on start up.


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## Micah (Jan 19, 2011)

It is very likely a failing cap. Also check the fan/motor mounting bolts and make sure they are sufficiently tight. 

On a related note, shorting caps to test them or discharge them is bad for them.


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## heatycooly (Mar 11, 2011)

Discharging caps is something you must do before testing. A cap stores energy and if you don't discharge it could hurt you better safe then sorry.


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## Jackofall1 (Dec 5, 2010)

Sure it might be the capacitor, but the motor is also 17 years I think you said, the noises you are hearing undoubtledly are from the tired bearing of the motor allowing the fan wheel to make contact with the scroll.

While you have everthing apart replace the motor to.

Mark


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## heatycooly (Mar 11, 2011)

If the motor is not over amping and starts fine with a new capacitor why would you replace the motor? On a 17 year old system, it isn't worth putting that kind of money into it a capacitor yes a 300 motor no


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## Jackofall1 (Dec 5, 2010)

Last time I looked a 3/4 hp motor was $130 maybe you sell them for $300++ but it sounds like this poster is DIY'n it. 

I would replace both while I had it apart.

Mark


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## heatycooly (Mar 11, 2011)

Your right that motor is cheaper cash and carry all I am getting at is look at all options I would hate to have someone dump a bunch of money into an aging furnace to have another thing go right after it an old system can nickel and dime you. I would do the quick fix and save for a new furnace


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