# Furnace blower slow to no start



## sureshot006 (Sep 8, 2010)

wife called me at work the other day and said no air was blowing even though the AC unit was running. Had her try a couple things to narrow it down. Found out the motor did in fact have power and was trying to start. Later on it started running on its own.

I took the blower/capacitor out and cleaned the fan and noticed more grime on everything than should be normal. So yeah i have to seal up the filter better. But anyway, turning the motor shaft by hand is smooth but more resistance than I expected. No play in it to suggest bad bearings but when running it does make a little noise but doesn't sound like worn bearings to me.

I put it all back together and flipped it on. It took about 30 seconds of sloooooowly winding up to get running.

Bad capacitor? Bad motor?


----------



## Woodstock (Sep 9, 2014)

Bad bearing
It should turn with virtually no resistance.
Add to that a dirty commutator, worn brushes, weak springs and it will make it worse. Could be the capacitor but any resistance on bearings would worry me.

I'd replace the motor.


----------



## #1wallygator (Jan 31, 2017)

sureshot006 said:


> wife called me at work the other day and said no air was blowing even though the AC unit was running. Had her try a couple things to narrow it down. Found out the motor did in fact have power and was trying to start. Later on it started running on its own.
> 
> I took the blower/capacitor out and cleaned the fan and noticed more grime on everything than should be normal. So yeah i have to seal up the filter better. But anyway, turning the motor shaft by hand is smooth but more resistance than I expected. No play in it to suggest bad bearings but when running it does make a little noise but doesn't sound like worn bearings to me.
> 
> ...


Does it have oil ports?


----------



## sureshot006 (Sep 8, 2010)

#1wallygator said:


> Does it have oil ports?


I dont think so? Didn't see any caps/plugs that I recall


----------



## ESOX (Nov 20, 2000)

Weak start capacitor would be my first thing to check.


----------



## sureshot006 (Sep 8, 2010)

ESOX said:


> Weak start capacitor would be my first thing to check.


It probably shouldnt have 0.L on the multimeter, eh?


----------



## jjlrrw (May 1, 2006)

Does your meter have a capacitance reading setting uF? O.L sounds like maybe you're in resistance mode.

I would measure the cap as a quick starting point, I would think a bad motor could weaken the cap over time. Maybe get the motor moving freely and swap cap if the reading is off motor replacement may be in the near future?

This guy explains it pretty good if you can stay awake.


----------



## lewisg (Jun 28, 2006)

Is the fan direct drive or belt driven?

The multimeter would have O.L. after it charged the cap for awhile with the testing power from the meter. Not an accurate way to test a large cap. For the price I'd replace it.

Also is the supply air side open enough not to cause a problem i.e. dirty filter? Test it with the filter removed.


----------



## sureshot006 (Sep 8, 2010)

lewisg said:


> Is the fan direct drive or belt driven?
> 
> The multimeter would have O.L. after it charged the cap for awhile with the testing power from the meter. Not an accurate way to test a large cap. For the price I'd replace it.
> 
> Also is the supply air side open enough not to cause a problem i.e. dirty filter? Test it with the filter removed.


Direct. Motor starts the same whether filter is in or out, but yes it is time to replace. Measuring capacitance I get 6.87 uF (spec is 7.5 +/- 6%). I am not sure how accurate my harbor freight super duper meter is.


----------



## sureshot006 (Sep 8, 2010)

jjlrrw said:


> Does your meter have a capacitance reading setting uF? O.L sounds like maybe you're in resistance mode.
> 
> I would measure the cap as a quick starting point, I would think a bad motor could weaken the cap over time. Maybe get the motor moving freely and swap cap if the reading is off motor replacement may be in the near future?
> 
> This guy explains it pretty good if you can stay awake.


Yes my fluke was in resistance. Had to get the cheapy meter out to measure cap. I get a value but not sure how accurate the meter is.


----------



## jjlrrw (May 1, 2006)

sureshot006 said:


> Direct. Motor starts the same whether filter is in or out, but yes it is time to replace. Measuring capacitance I get 6.87 uF (spec is 7.5 +/- 6%). I am not sure how accurate my harbor freight super duper meter is.


I have a few HF meters (the ones they give away) they seem pretty accurate when working compared to my Fluke, but they have cheap leads and not may functions. If you're getting a repeatable solid reading discharging the cap in between I would trust the meter. Cap is almost outside the tolerance, Bring the old one with you and the hardware store may have a better meter to measure new and old.


----------



## sureshot006 (Sep 8, 2010)

jjlrrw said:


> I have a few HF meters (the ones they give away) they seem pretty accurate when working compared to my Fluke, but they have cheap leads and not may functions. If you're getting a repeatable solid reading discharging the cap in between I would trust the meter. Cap is almost outside the tolerance, Bring the old one with you and the hardware store may have a better meter to measure new and old.


Coworker told me he has a whole 1/3 hp motor, fan and cap sitting in his barn collecting dust. Gonna just swap and see what happens!


----------



## Forest Meister (Mar 7, 2010)

Better to find out the motor is bad now then in winter. I do not have air and over the years have had two go out in January/February. I think they both went out on a weekend too. FM


----------



## CrawlerHarness (Dec 9, 2017)

Sure sounds like the motor needs replacement. Unless your A-Frame coils are frozen over. But that wouldn't give your exact details of symptoms.


----------



## Quack Addict (Aug 10, 2006)

The best way I have found to test capacitors is to charge it up, then give it a quick underhand toss to your wife or friend. They will tell you right away if it works or not.


----------



## 6Speed (Mar 8, 2013)

Quack Addict said:


> The best way I have found to test capacitors is to charge it up, then give it a quick underhand toss to your wife or friend. They will tell you right away if it works or not.


Or get them to lick the leads and tell you if it tastes like a lemon...


----------



## Nostromo (Feb 14, 2012)

6Speed said:


> Or get them to lick the leads and tell you if it tastes like a lemon...


At last. 
The engineer's approach to problem solving.


----------



## sureshot006 (Sep 8, 2010)

Update: coworkers blower assembly had a 10 uF capacitor. I put it on my motor and it fired right up. However... when the blower stopped there was a screech sound (fan not touching anything). It smelled a little hot too. So I think the motor is going bad but the extra oomph from the larger cap got it to run.

I ended up putting the new (used) motor and cap in my furnace and all is good.

The bad motor has a noticeable sticky spot when turning the shaft by hand.


----------



## Woodstock (Sep 9, 2014)

I figured so


----------



## Woodstock (Sep 9, 2014)

Those bearings are subject to a lot of stuff (thrust and other forces) at 1750 rpm that we can't feel by hand at virtually no speed.


----------



## sureshot006 (Sep 8, 2010)

Woodstock said:


> Those bearings are subject to a lot of stuff (thrust and other forces) at 1750 rpm that we can't feel by hand at virtually no speed.


Yea I was just surprised how weak it was starting when I could spin it by hand with little effort.


----------



## Team Camo (Mar 11, 2014)

sureshot006 said:


> Yea I was just surprised how weak it was starting when I could spin it by hand with little effort.


Glad ya got her going...gonna be a hot one tomorrow.


----------



## sureshot006 (Sep 8, 2010)

Team Camo said:


> Glad ya got her going...gonna be a hot one tomorrow.


Yea gotta get some fishing in before it gets too uncomfortable out there


----------



## kroppe (May 7, 2000)

Screech sound is bearings. Bearings are also a candidate cause for slow startup. 

Classic throw parts at it situation. It sounds like the unit is not new, is this correct?

If it were mine I would replace:

capacitor

Bearings

Relay if there is one, forget what it’s called, maybe it’s a motor starter. The mechanical high current switch.


----------



## sureshot006 (Sep 8, 2010)

kroppe said:


> Screech sound is bearings. Bearings are also a candidate cause for slow startup.
> 
> Classic throw parts at it situation. It sounds like the unit is not new, is this correct?
> 
> ...


A coworker gave me a whole fan/motor/capacitor. I took the motor and capacitor and swapped them. All good now.


----------



## CrawlerHarness (Dec 9, 2017)

sureshot006 said:


> Update: coworkers blower assembly had a 10 uF capacitor. I put it on my motor and it fired right up. However... when the blower stopped there was a screech sound (fan not touching anything). *It smelled a little hot too. *So I think the motor is going bad but the extra oomph from the larger cap got it to run.
> 
> I ended up putting the new (used) motor and cap in my furnace and all is good.
> 
> The bad motor has a noticeable sticky spot when turning the shaft by hand.


I don't think that IronMan can smell heat......who did you say you were again?


----------



## sureshot006 (Sep 8, 2010)

CrawlerHarness said:


> I don't think that IronMan can smell heat......who did you say you were again?


I can smell heat the first time the heat kicks on in fall. Also electrical components overheating.


----------



## Woodstock (Sep 9, 2014)

The smell of heat from electrical components could be ozone, which is caused by arcing between brushes and the commutator.

The smell from the first heat cycle of the year, I believe is caused from dust being burnt off.


----------



## sureshot006 (Sep 8, 2010)

Oh, one thing about the motor. It doesn't have bearings. It is an oiled bushing.


----------



## Woodstock (Sep 9, 2014)

https://www.google.com/search?clien...jYuMZgBAKABAcABAQ&sclient=mobile-gws-wiz-serp


----------



## 22 Chuck (Feb 2, 2006)

sureshot006 said:


> I can smell heat the first time the heat kicks on in fall. Also electrical components overheating.


My wife can smell the first heat, sometimes I can also-hot water boiler.


----------



## sureshot006 (Sep 8, 2010)

CL-Lewiston said:


> My wife can smell the first heat, sometimes I can also-hot water boiler.


Unique scent, like smelling a spring rain before it arrives.


----------



## Woodstock (Sep 9, 2014)

BTW, I have seen bushings that were bad/lost oil but usually it's poor heat treatment on the shaft.


----------



## sureshot006 (Sep 8, 2010)

Woodstock said:


> BTW, I have seen bushings that were bad/lost oil but usually it's poor heat treatment on the shaft.


I just got done cleaning the motor shaft and oiling the "felt" or whatever it is. Not really surprised it only lasted a day since it sat for years... it seized up this afternoon. Probably exact same issue with my old one.


----------



## Woodstock (Sep 9, 2014)

Bummer
Much more susceptible to contamination, no seals.

Fastco Motor by chance?


----------



## sureshot006 (Sep 8, 2010)

Woodstock said:


> Bummer
> Much more susceptible to contamination, no seals.
> 
> Fastco Motor by chance?


GE


----------



## sparky18181 (Apr 17, 2012)

sureshot006 said:


> GE


You are gonna put those HVAC guys out of business. At least now you ll get a new one and be good.


----------



## sureshot006 (Sep 8, 2010)

sparky18181 said:


> You are gonna put those HVAC guys out of business. At least now you ll get a new one and be good.


Ya I guess. Sorry but I'm not paying $700 or whatever to swap something that takes literally 15 minutes and removing/reinstalling 3 screws.


----------



## sparky18181 (Apr 17, 2012)

sureshot006 said:


> Ya I guess. Sorry but I'm not paying $700 or whatever to swap something that takes literally 15 minutes and removing/reinstalling 3 screws.


Totally agree. It’s getting to which part you actually need to replace is sometimes the hard part. The actual job is easy.


----------



## sureshot006 (Sep 8, 2010)

sparky18181 said:


> Totally agree. It’s getting to which part you actually need to replace is sometimes the hard part. The actual job is easy.


Yep. If it was single digits outside I'd take a differen route


----------



## micooner (Dec 20, 2003)

sureshot006 said:


> Ya I guess. Sorry but I'm not paying $700 or whatever to swap something that takes literally 15 minutes and removing/reinstalling 3 screws.


Don't know who your power company is but dte offers some sort of rebate for updating your blower motor to a ecm type.


sureshot006 said:


> Ya I guess. Sorry but I'm not paying $700 or whatever to swap something that takes literally 15 minutes and removing/reinstalling 3 screws.


----------



## sureshot006 (Sep 8, 2010)

micooner said:


> Don't know who your power company is but dte offers some sort of rebate for updating your blower motor to a ecm type.


DTE. I will have to look into rebates.


----------



## Papa Liver (May 20, 2016)

Hit up Charlie (Ol Tom Killa). He got me an insane deal on a brand new furnace last year.


----------



## sureshot006 (Sep 8, 2010)

Papa Liver said:


> Hit up Charlie (Ol Tom Killa). He got me an insane deal on a brand new furnace last year.


Might end up looking at them before winter. Mine is 22 yrs old.


----------



## micooner (Dec 20, 2003)

sureshot006 said:


> Might end up looking at them before winter. Mine is 22 yrs old.


We just had randazzo out. Ours is 25 years young. 3 options 100000 btu furnace, and ac. 3.5 ton from 7500 to 8500$ depending on efficiency rating.


----------



## sureshot006 (Sep 8, 2010)

micooner said:


> We just had randazzo out. Ours is 25 years young. 3 options 100000 btu furnace, and ac. 3.5 ton from 7500 to 8500$ depending on efficiency rating.


Wow thats a lot more than I thought. I was anticipating around 4-5k


----------



## micooner (Dec 20, 2003)

sureshot006 said:


> Wow thats a lot more than I thought. I was anticipating around 4-5k


They were within 500$ of the other 2 estimates and one was from a close friend.


----------



## sureshot006 (Sep 8, 2010)

micooner said:


> They were within 500$ of the other 2 estimates and one was from a close friend.


A buddy of mine went all new last year and I think first guy was 6k, next was 4k. Things are probably a little more pricey at the moment.


----------



## micooner (Dec 20, 2003)

Don't know but if you get a 5000 or under quote send em my way. Lol


----------



## Mark4486 (Oct 14, 2015)

micooner said:


> Don't know but if you get a 5000 or under quote send em my way. Lol


Pm me. I do furnace and a/c for under $5000.00. I am a professional.i can pull permits and have a mechanical license.


----------

