Motor question for HVAC guys

[BillK]

I know there are a few guys here that do HVAC work for a living. The blower in my furnace has started getting pretty noisy. I am going to take it apart tonight and take a look at it. Is there any sense in even trying to clean it and lube it ? It is about 14 years old. This is the motor that it uses:

https://www.supplyhouse.com/Nordyne-902128-1075-RPM-4-Speed-Blower-Motor-1-2-HP-CCW-115V

I dont mind replacing it but if a good clean and lube will take care of it I am like everyone else and don't mind saving a buck for now.

So what have your experiences been ?

 

[acmikee]

most motors that size are sealed.. do you really need a 4 speed motor.
just match RPM, frame size, HP, voltage and amps

 

[BillK]

most motors that size are sealed.. do you really need a 4 speed motor.
just match RPM, frame size, HP, voltage and amps

That is the correct replacement motor for the furnace and I know it will fit I don't have time to fool around matching sizes etc etc. I am going to pick one up at a local HVAC warehouse on my way home and have it if I need it.

 

[48RON54]

Not an HVAC guy

Mine got noisy and up and died one day. I took a look at how much dirt/lint dust was covering it and figured I could just pull it, clean it up real good and reinstall.

It started working again, and lasted 1 day before it died again. Given how long it took me to pull it, clean it and reinstall it, I wasn't happy to do be doing all that a second time given the price of the replacement motor was only $120 or so.

 

[MFolks]

Washing machine,and clothes dryer motors used to be rebuildable,but now they are welded together,"Beer can motors" when they quit working,throw them away...

 

[metlmunchr]

It's worth a try, but I've found a lot of the time the noise will be related to excess wear of the thrust washers rather than a lack of lube or worn radial bearings. If you push and pull in and out on the shaft, it shouldn't move much at all. Worn thrust washers will let it move in and out in the 1/4" range. Typically they'll be noisy for a while, but as wear progresses they eventually get to the point where the rotor drags and the motor will run slow and overheat.

 

[Jim greengo]

most motors that size are sealed.. do you really need a 4 speed motor.
just match RPM, frame size, HP, voltage and amps

What he said

 

[Jim greengo]

That is the correct replacement motor for the furnace and I know it will fit I don't have time to fool around matching sizes etc etc. I am going to pick one up at a local HVAC warehouse on my way home and have it if I need it.

The supply house can size a 3spd motor to drop right in same as the 4 spd in most cases.

 

[yeldogt]

If that's the original motor -- I would replace with same. If you think it's a replacement in there I would at least check to see what was the original motor.

I like supply house .. it's my go to spot when not going to my local supply house.

As others have pointed out ... don't try and fix

 

[LS6 Tommy]

most motors that size are sealed.. do you really need a 4 speed motor.
just match RPM, frame size, HP, voltage and amps

Many of those motors on better units have oil ports. They usually have littel yellow or black plugs in the ports. If he has heat & A/C, he needs at leas two speeds, and if the system was set up properly, the speeds were set based on temp rise for heat and temp drop for cooling.

Tommy

 

[Milton Shaw]

Make sure you clean and scrub the fan blade when you have it off. Also reach up and brush out the evaporator if you can reach it. A lot of dirt can stick to a fan blade over 15 years of use and will effect the balance of the blade to. Put the same 4 speed back in, it's what the furnace is designed for.

 

[BillK]

Many of those motors on better units have oil ports. They usually have little yellow or black plugs in the ports. If he has heat & A/C, he needs at least two speeds, and if the system was set up properly, the speeds were set based on temp rise for heat and temp drop for cooling.

Tommy

Yes, 2 speeds set up. I started to look at it last night but decided to wait till the weekend when I have more time. I have to take the bifold door off the closet to get the blower out. It only made the noise that one time a few nights ago and it almost sounded more like an air flow induced "vibration" ? I cleaned the electronic air cleaner and the prefilters and I could spin the blower by hand and it felt nice and smooth. Who knows. I will take it apart this weekend and clean everything out real good. If there is any question on the motor I will replace it.

 

[BillK]

Put the same 4 speed back in, it's what the furnace is designed for.

I agree. Don't know why guys want to cut corners on stuff like this.

 

[Jim greengo]

I agree. Don't know why guys want to cut corners on stuff like this.

It's not cutting corners,but whatever makes you happy.

 

[Innovate1]

Most older motors of this type have sleeve bearings. A lot of newer ones have ball bearings. You can take out the through bolts and remove one end shield to see which type you have if it isn't obvious. I can't tell from the pics. If they are ball and everything else looks ok - not overheated you can try replacing the bearings. If you turn the old ones it should be easy to tell if they are bad - they will feel like they have a bit (or if really bad a lot) of grit in them. You need a way to press the bearings onto the shaft - press on only the inner race or you may damage the bearing and they will fail early.
The other big failure point is the capacitor. Measure the capacitance if you can and replace if it is more than about 20% low.

 

[Mr. T]

I’d pin down what was causing the noise before I’d throw a motor at it.

 

[BillK]

I’d pin down what was causing the noise before I’d throw a motor at it.

Oh, absolutely. It has been totally normal for three days so who knows. It cant hurt to take it apart and do some cleaning anyway. Good Labor Day Weekend project

 

[phansen39]

Many of those motors on better units have oil ports. They usually have littel yellow or black plugs in the ports. If he has heat & A/C, he needs at leas two speeds, and if the system was set up properly, the speeds were set based on temp rise for heat and temp drop for cooling.

Tommy

No they don't. Good equipment/motors use ball bearing motors

 

[Innovate1]

^^^ What he said. They don't. At least not recent motors in direct drive blowers. I work in the industry. Most if not all the good motors use ball bearings and I would venture to say most of the lower quality ones do too. It's been that way for many years.

 

[TRWham]

I realize this is an existing system, so replacing the PSC motor may make sense, but ECMs are the only logical choice for new equipment. Lower energy consumption, variable speed, ball bearings, longer life. They do everything you need short of mixing cocktails and waxing your car.

 

[LS6 Tommy]

No they don't. Good equipment/motors use ball bearing motors

^^^ What he said. They don't. At least not recent motors in direct drive blowers. I work in the industry. Most if not all the good motors use ball bearings and I would venture to say most of the lower quality ones do too. It's been that way for many years.

Over 35 years in "the industry". Changed out literally hundreds of them and freed up and lubed probably 1/8 of that, so allow me the courtesy of rephrasing my original post. Many of the older, better, non-ball bearing motors have oil ports.

Tommy

 

[phansen39]

Reasonable mr tommy.. But how many Duomatic Olsens have you seen in the last 20 years.