Belt tensioning for belt drive blowers 

I have an old Lennox furnace that none of the HVAC companies will touch . But they won't tell you that over the phone. They'll come out and give you a sales pitch for a new furnace and then charge you $130 for the privilege. Since the old guy that used to service my furnace passed away I'm the tech for simple maintenance. Luckily Mr Johnson always showed me exactly what he was doing. Anyway in getting old Bessie ready for the season I noticed the belt seemed loose. I ordered a new one on Amazon and came to youtube to find out how to adjust the tension. Thanks for saving my bearings. If I had figured out how to adjust the tension I would've adjusted it to one inch deflection and boom. Thanks again.

Thank you for all your videos. I really enjoy that your focus is always troubleshooting, finding the cause or possible causes, and giving physical examples and explanation. Much appreciated. Please keep it going as many of us enjoy solving mechanical problems daily!

The guys made fun of me for signing up for a Belt Seminar (Browning) but wow probably one of the best seminars I have been to. The energy the building owner will save by having a proper calibrated belt tension by using a belt tension-er is amazing. We do not have special calibrated fingers.....

I like the way he explains , he is very knowledgeable , and I would like to ad something and I hope you don’t mind, this is what I do. The amount of deflection you should get is approximately 1/16 to 1/8” per foot. If the belt is set too tight, the bearing or mount may fail,if the belt is too loose, it may cause the belt to overheating and crack

It makes sense, Yes. I always thought that the belts needed to be tight. I know better now. Thanks for the useful video.

I would agree on tension if you are talking about fractional hp blowers. A and B belts are normally tightened with the usual 1" depression or with a tensioner. Bearing overheat from what I have seen is unusual if the bearing is not worn out. Especially if the bearing is the ball type. Thanks for the thoughts. GFM

Yes, that's the jam nut used to keep it tight. It is not actually changing the adjustment of the belt although it could be if it was left loose. The pulleys are aligned correctly as far as can be. Note the rubber mounts limit the amount of tension that can be pulled without misalignment. Also the bearings wont take much load. This is not to say a blower over 1hp should done this way. This only for smaller fractionals. Thanks for the close look. GFM

The furnace in our apartment has a belt drive blower. The previous tenant neglected to change the filter, so the blower is very dirty. I cleaned what I could, but there is still a loud squeal at startup and then it sounds like a dryer full of clothes while running. I can get use to the sound of it running, but the startup is enough to bring you out of your bed at 2:00 am in the morning. I've got a video of it in my library. Thanks for any input!

Oh no! The nut is backing out! What a tense video!

valuable point you make about the belt tension, thank you...

Just want to say thanks. furnace went out this weekend. Paid $400 emergency service. guy hooked up a light switch and put on a new belt. Must not have known what he was doing as the switch was way out of code 1/4 of the box was missing and the 1/2 hp Westinghouse motor failed later that day. Tech never back came out. Wouldn't have matter anyway as I'm sure he did not have that motor and if he did, he would have charged me an arm and leg for it. I checked the tension and it was very tight. Pulled the motor and the bearings are bad. I ordered a new motor $99 bucks, cause I dont want to keep on messing with something when my family needs heat now. But thanks for the video, at least I know how the tension should be.

Good demonstration video. I have a belt tension tool somewhere. I need to dig out and start using it.

i have had to go behind several people and release tension,a lot of people thinks they have to be really tight,i tryed explaining this to a new tech 1 day and of course he did not listen,had to go back a few weeks later and replace bushing and rubber mounts,i had a better,firmer talk when i got back to shop,he had no choice but to let it sink in that day i was pretty hot,he did 2 that day and he repaired the 2nd,just out of hvac school he knew it all but had a lot of callbacks,

Very good tips on adjusting belt. Thank you

The belt manufacturers say they will operate normally with proper tension on startup. However, I dont see any problem with your method. Thanks for the comment. GFM

Performing a static pressure test unloaded will most times give you a non static difference. Place a load on the blower from coil resistance and a heat exchanger and the same test would have show the belt will slip under load conditions. So a properly tensioned belt is critically important.

Great info. other videos don't say about those details.

That one is hard to get through, especially to someone who has done automotive. Even the 4Lbelts are not suitable to be that tight. Great comment from someone that knows! GFM

Thank you from Canada great video

Thank you for the video a lot of good information.

Once the set screw is loosened, it should come off with some light tapping on the pulley. If not, a 3 jaw puller can be used. I will be doing a vid on this soon. GFM

I was suspecting that. Thank you for the response.

I was realllllly was looking for HOW TO TIGHTEN THE BELT.

I have noticed that when I place a new belt on obviously, they are a lot stiffer than the old belt that comes off..... I usually give it just enogh tension to stop slipping on start up, let it run a bit and re-check and or re-tension if necessary.... I have seen over tight belts make those small motors run HOT before.....

Thank you for sharing this video I just wondering what size belt that was it's almost identical to the setup I have at my house and thank you for letting us know that not to over tighten it also can you let us know how to oil the parts or what should be done thank you

Thanks for sharing. 😀

RPM's are RPM's, overtight will affect the bearings both driving and driven. If a motor runs hot it's the bearings heating the shaft then radiating through out, secondary is the motor fighting its own bearings to turn. Correct belt tension? as loose as you can without belt slip or tossing the belt.

I realize that motor isn't what I'm used to but is it supposed to be that loose?

What do u think about adjust belt tension to spec in the install manual, for example 100 lbs for a new belt 80 for a worn in belt. Do u thinks that's to tight

He doesn't Show Us HOW to Tighten the Darn Belt!!

I installed a new motor for a whole house fan 1/3hp and the belt went on fairly easily. Anyhow the motor runs 10 seconds and kicks off, do you think the belt maybe too tight? I didnt adjust anything from previous motor but this motor physically larger and has no capacitor. Trying to figure out why it shuts off after only 10 seconds of running.. It is a brand new Dayton 6k778 belt drive motor.. Tomorrow I am going to check the tension on it, I wouldnt think thermal protection would kick in literally 10 seconds in.. Anything you can chime in on would be appreciated.

I have this style of blower that has a belt and 2 pulleys, it randomly squeals, I replaced the motor and belt and it squeals/hums, through vents, do pulleys need to be lubricated?? Or should I try taking out blower and giving it a good cleaning

thanks for sharing...

hey how are ya?? I am getting a seizing noise coming from my belt drivin blower motor area but can't see anything not turning ~ any advice? blower cage bearings replaced as well as the furnace motor brand new~ 2002-2003 that's only 14/15 years... help!!!! it's pretty damn cold today in Calgary Canada

Can I convert to the new style blower motors that have various speeds ? My belt driven one doesn't cool the house because it hardly pushes any air out

I think my dad has been using WD40 on the motor and fan axels/bearings . 😱 Is this really bad? Don't we need grease/oil ? The belt doesn't seem to be too tight although I tried to put it on a tight as possible after our neighbors welded one of the 3 brackets that broke on the fan. This summer the motor is getting wicked hot and causing the thermal protection trip to stop inside blower while outside unit still kicking for nothing. It doesn't seem to spin all that freely ATM but it definitely turns

thank you

How would I remove the pulley of the motor shaft.

My oil furnace comes on but blower comes on when the chamber is hot is that normal then furnace shots off and blower continues thermostate is right on old oil beckett furnace

Would a bad belt cause the blower to shake when on? Or is it an alignment issue? Thanks

HelloI have been having problems with my have that is similar to yours The bearings Went bad So I replaced them with new ones with new housings that have grease fittings.Seems that everything is ok till the motor gets hot and shut down From getting to hot.Do you think if the belt was to tight it would cause overheating of the thermals on the motor ?Thanks

I would have appreciated a little less talk and more demonstration. My cooler belt is too tight and I know how to adjust that. I just needed to know if that was the problem.

how long do belts generally last

Where do you get replacement belts? Is it just a regular automotive fan belt?

If it's over tightened Can the motor overload and thermally shut down

the belt's vibrations and deflections showed that the belt was too loose, and will decrease belt life

My belt keeps breaking. replaced it last winter, just broke again. I replaced the belt with the same model as the previous, but it's a used house so for all I know it could have been the wrong belt in the first place. Any advice?

It" s OK but how exactly you tight the belt?

Our installation of v-belt: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-s7RZkYbHhmc.html

Belt alignment here. ru-vid.com?search_query=adjust+motor+sheave

That belt the second time is not tight.

531st like

Your motor is flipping all over the place.!!! Good grief.

really you didn't even show how we tighten the belt. most stupid how to video I ever seen. doesn't even show how to tighten it yet the title says that's what its about

TALK FASTER UGH