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!

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

Very good tips on adjusting belt.  Thank you

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

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.....

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!

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

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

I was suspecting that. Thank you for the response.

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

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

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

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

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

Thank you for the video a lot of good information.

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,

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

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

Thank you from Canada great video