UPDATE - Loud Bang When AC Turns Off

[@JoesGarageProductionsLLC]

Special thanks to KZbinr matt luongo for helping me figure out the root cause of this banging noise!

[@realdmc]

Man, this is awesome! I had a friend share this with me this morning. My week-old American Standard unit was doing this. Had the tech here this morning for over an hour and he couldn’t diagnose. They’ll be back out tomorrow, with a senior tech, but I shared this video with them this afternoon. Since it’s new, it should be covered by warranty but I’m not sure they would’ve figured this out without me sharing the video. Probably saved them and me time and money on a warranty replacement for a new unit.

[@JoesGarageProductionsLLC]

Glad it helped you! I've seen quite a few units with this issue across several different brands.

[@KidBako]

Came across your video today. Thank you very much. I'm sure my next door neighbor who hears the unit would thank you even more! LOL. I had the exact same noise when our unit shut off. I pulled the fan and sure enough, the collar was loose. My simple fix was using a drill punch to make dimples all around the circumference of the pressed fitting on the opposite side of the collar. Again, thank you

[@cmoore8434]

I was wondering if there was a way to make the fan hub tighter around the motor shaft. Your idea sounds good! Do you have a video recommendation for that? I'm a broke novice.

[@johna1060]

Great video, to answer your question. Just junk the old fan. Not worth keeping IMHO. Your AC is working so that's what matters. Thanks for posting.

[@JoesGarageProductionsLLC]

Yeah this has since happened to my other ac. I tried staking The hub to the fan again and a couple months later it's happening again so it must have loosened up.

[@ncvman]

Thanks for video my 1 year old trane doing the same thing. Put in request for warranty repair. Update: Company wants to charge me diag fee and labor fee to replace this even as its under warranty. I bought the part online and saved me some money! Thanks.

[@sethmiller8318]

We have the same problem! I was dreading calling out a HVAC company and have them tell me it needs to be replaced. We just bought our house, the people that installed the HVAC did a hack job. I found your video, and I am getting my tools ready to go fix ours! Thanks for the video!

[@JoesGarageProductionsLLC]

Glad I could help! I was panicking too... Turned out to be a super easy fix and has been working great since!

[@jima3129]

You should have put blue loctite on the set screw. I assume you set it on the flat of the shaft?

[@nooksolo]

​@jima3129 you don't need loctite on a cfm hub. Nor would I recommend it.

[@keithhiat2214]

Thanks for this video, it helped a lot. My AC made that loud bang but it went away so I didn't replace the fan blade. Later the bang came back and I didn't have the money to replace it. Sometime later it started making a loud rackety noise so I shut it down to prevent further damage and ordered a new fan blade. I just installed it and the system is purring like a new system. You saved me hundreds I did not have. Thanks a million.

[@tjjoseph333]

Fantastic! Have the clank and will inspect in the morning. Thanks so much!

[@johndearmond9582]

Our ac has the same issue. Hope the fix will be as easy as a quick tak tak tak from neighbors welder. I’ll keep you posted.

[@JoesGarageProductionsLLC]

Welding should do it, but just be careful welding galvanized material

[@dpsimpsoniii4955]

Thank you, my unit does the same thing intermittently on shut down, and yet it still works. I had a professional come out and they couldn't duplicate the problem and everything checked out good. So I thank you for the information. 👍

[@PilotInCommand777]

I know this is an old video but..... I had this issue for over a year and just checked and this was the issue.. THANKS!!!!!!!!!!

[@walterbreen9406]

Thanks for the help you gave me the info needed to find my noise. My issue was similar with looseness in this location, but the sound was constant after the fan would start. (FYI, I did have the banging when stopping for a long time but could never find the issue) The crimped inner collar was allowing the fan blades to spin around the hub, and it was very loud. My fan assembly showed no indications of rust where the two parts were rubbing against each other. I should say the sound could be intermittent, if the parts jammed together it may run for days with no noise. I was only able to cause minimal slippage when I forced it by hand, but the power of the motor could dislodge it and would be very noisy the same banging noise in this video but repeating very quickly sounding like the fan motor was going to come apart when running. I actually thought it was the compressor at first. By electrically disconnecting the compressor then fan I was able to isolate it to the fan assembly making the noise. Thanks again what a life saver.

[@JoesGarageProductionsLLC]

No problem - glad it was helpful! I thought my compressor was failing as well.

[@joeramos8873]

Thank you as well & Matt Luongo. Going to replace mine tomorrow. I tried hammering it but no success. The sound is not as loud as the AC is still operational, more of an annoyance I guess. Update: I was able to successfully hammer my hub down where there’s no more movement. We decided to uninstall the new one & reinstall the old one. So far no more noise! I’m going to keep the new for 30 days just in case.

[@cmoore8434]

By "hammer it down", do you mean you used a hammer to dent the fan hub so it would hold better onto the shaft?

[@chuck889]

I think you just helped me figure out my issue. Mine does the clank at the beginning as well. Maybe I can replace it at midnight when it's only 90 degrees outside lol

[@johnwentz3925]

Exact same noise on shutdown happens when the fan mounting nuts are loose. Mine was banging for almost a year. The tech told me I needed a new compressor. Brand new system. Tightened the mounting nuts for the fan and the bang noise is gone. Shuts down so quietly now.

[@kernalrom]

Yup.. Never trust those guys.. Ever

[@lyndiem230]

our TRANE was installed March 28th and has made that bang everytime it shuts down. I got the AC company to replace the compressor under the warrenty, and yet we still have the BANG on shutdown. The AC tech was at a loss what to do. Thankfully this You Tube video about the fan hub and shroud screws may be our answer.

[@lyndiem230]

AC tech is hear now, and tighten the bold, but still have th BANG. He's going to see if the coollant coming in the line is constricted or hits something when the unit turns off causing the outer metal shell to hit something

[@werquantum]

@@lyndiem230 And?

[@musclecarsrt2324]

Same thing happened to my Beckett oil burner fan. I thought it was the motor but upon inspection I found the same thing.. Replaced the fan cage and all was good. 👍🏻

[@albertastorms]

My 1997 Honeywell (Which really is a Lennox with a Honeywell badge) central air conditioner condenser unit still has the original 4 blades, though it is a 4.5 ton unit. I don’t know if Honeywell put their badge on their units that they had Lennox make back then only here in Canada or if they also were available in the USA with the Honeywell Badge. Mine is a Puron or R410a unit back when that was a new refrigerant that had been out for only 2 years at the time. They costed more upfront but they also had a Freon or R22 units available for less then too. Either way it has been reliable so far with the typical wear parts like the capacitor being replaced once. For the gas furnace the ignitor and the pressure switch being replaced recently. Other than that they have been dependable. The AC survived the heatwave of 2021 when we hit 116°F with a 133° Heat Index. This summer we hit 111°F with a 120 heat index in the middle of july. Yesterday we were 98°F and today is only going to be 93°F.

[@dhal6271]

My Copland scroll makes a bell ringing noise only when it shuts down. I think it is the back check valve? Fan hub is fine

[@PilotInCommand777]

Instead of welding I put the fan hub in a vise and used a chisel and hammer, carefully re-peened the old peen marks on the back of the hub and it tightened the hub up nicely. Thanks again for the info!!

[@JoesGarageProductionsLLC]

I actually did just that on my other AC, that started to have this exact problem. That was a couple of months ago and so far, so good!

[@wkegger]

Thank you! My A/C is making the same noise and it’s the next thing I’ll check. 👍

[@ronc4500]

Just started hearing the same sound from our American Standard unit that's just under two months old. Called our HVAC company out and the tech stopped the unit from the outside by pulling off one of the wires. It didn't make the noise. He tried it a couple of times and nothing. After he left I turned the thermostat down to turn the unit on. I let it run for a minute then raised the thermostat to cut off the AC. Bang! The noise was there again. Called the HVAC company back and sent them a video so they could hear it. They are contacting American Standard to see how they want to proceed with the issue and warranty.

[@SwanseaTitanFan]

What happened?

[@PJ-ee5mc]

Great info, Joe! One quick cold weather question if I may: When you are trouble shooting a heat pump and turning it on an off, are you just leaving the furnace in a state of "call for heat" and then using the heat pump's 'fuse block' to start and stop the unit itself, or are you turning the furnace on and off each time? OR.... are you 'jumpering' some contacts on the heat pump to fire it up just for testing? I have always wondered what goes on with this. I am in a situation right now where I need to figure this out so that I can bypass the comp, then the fan and even check out if the contactor is acting up due to some noises I'm hearing. It seems a little silly to run in and out of the house each time. My plan was to pull the fuses, call for heat indoors and then plug the fuses in for testing and pull them back out between tests all while the furnace is still running. Does this make sense?

[@macmclain1350]

Tap on the contactor. That's how you check it.

[@godbwu]

Thanks for the good info, I’m going to check mine. Chunk the old fan. Let me know what dumpster it’s in, so I could “verify”. 😅

[@88drain35]

same problem...new factory fan fixed it ...ac company wanted relace whole unit...thank you

[@JoesGarageProductionsLLC]

Glad the video helped! The tip came from another KZbinr. Can't take full credit lol

[@dancrull1541]

Joes garage and Matt (KUDOS) welding might throw it out of balance? ?? Not sure ! But I pulled mine out and it wasnt as bad as yours but it was loose, I cleaned it up and took off all the crud and it makes no noise when starting and about 1/2 of what it used to be when shutting down. . Im ordering a new blade too. mines only a two blade and seems really flimsy! Hopefull the next one will be a bit heavier! Thanks for the help !

[@JoesGarageProductionsLLC]

Glad we could help! Welding probably wouldn't affect the balance too much as the mass of the whale would be very close to the axis of rotation. I thought about welding but then when I saw how inexpensive a new fan blade was and the obvious risk/challenge of welding galvanized I decided it wasn't worth it.

[@studlygoorite5955]

Thanks for the video, I have a loud clunk/rattle/whatever it is when I shut mine down. I just installed a compressor blanket that did not help the clunk. My hub is not loose like yours (with play side to side) but it does have play up and down. Can anyone tell me if this is normal or maybe my issue is similar but with the hub play up and down? Thanks PS, this clunk wakes me from a deep sleep for years now, tech came out and said this was normal.

[@infernoz0764]

My hub wasn’t notably loose but I showed the videos to technician and he swapped out the fan and motor and it’s all quiet now.

[@HPL5P]

Fixing mine tomorrow! Has been driving me nuts.

[@joseweisingerr7618]

I have a very similar banging on a Chinese portable AC PoloCool 53AP/C it also make noise but when the compressor stops. I took off the shell to see if there is something with that compressor but it’s not. I can’t find what’s doing the noice.

[@cindel8486]

Is there no way to adjust the hub itself to for example tighten it up on one side and loosen the other etc? As a certified bike mechanic this is common thing to do or service or check when working on or going through bike wheels is to check and adjust the hubs. OR would some lubrication help?

[@JoesGarageProductionsLLC]

My other AC started doing the same thing (9 yrs old), so I just peened the hub with a hammer and a punch. All quiet now!

[@sheltdog8463]

Great video! Hope this is the cure for mine.

[@albertastorms]

What happened is the fan blade manufactures that some HVAC manufacturers buy their parts from, were having quality control issues during Covid because of people not showing up due to covid policies that were in place at these plants. Therefore you are now seeing the result of that. There have also been issues with some through the wall exhaust fans that are used in warehouses, plants, greenhouses etc also having the same issues. That hub is somehow crimped or pressure fitted into the center hole, when they used to be welded. Welding did take more time in manufacturing as then there needed to be more balancing done to the fan. So by hand welding that fan you might throw the balance out.

[@allston1971]

You can tighten that hub up with a center punch. That is how I tightened mine.

[@anthonygarcia2267]

Wow...Mines been making that horrible noise too...going to check take mine apart and check it out..thanks

[@JoesGarageProductionsLLC]

My other unit started doing this and I just peened the hub with a punch on my annual maintenance a few weeks ago and a hammer and it has been fine since!

[@DJSubAir]

In a pinch could you not pound it with a hammer to close the gap slightly. If you couldn't weld it?

[@JoesGarageProductionsLLC]

Yep that is certainly possible. I had to beat it pretty hard with a sledge to take up the slop.

[@miltonorellana4362]

I had the same issue and i hit it with a hammer and it worked but you have to use a metal bed on the bottom to hit it right in the center and it worked

[@johnlang5010]

Thanks so much. Well done.

[@destinyreturns4885]

That was amazing.. Great post....

[@DJSubAir]

Hey did you ever end up fixing this blade or just chucked it in the bin?

[@JoesGarageProductionsLLC]

I ended up chucking it. Now the fan blade on my other AC is starting to make this noise. If it gets bad, I'll try welding it

[@TheMcGuireLife]

No, I wouldn’t bother fixing the old broken fan. Since you got it replaced, I would throw the old fan away.”

[@G1primo]

How urgent is this to fix. If my ac still working ? I plan on doing it but I am injured rn and can't use arms. Should I have someone come out or should I be good until next month when I can do myself.

[@JoesGarageProductionsLLC]

Not an urgent repair as long as the fan is still turning. My other unit started doing this for a few months and I just peened the hub a few weeks ago during annual maintenance.

[@lucindagaskill4519]

That bolt that was hard to remove, I can't get it off, so I can replace the fan. I soaked it in WD-40 over night but it won't budge. Any advice ?

[@hgodtx]

I wonder if getting a more engineered product for this specific purpose, such as Liquid Wrench, would make it happen! If not re-apply a few times for a day or two. If still not, two options. Hit it with a torch to expand the nut moreso than the shaft to break it free. Use a professional air impact wrench, hopefully you know someone with air tools.

[@JoesGarageProductionsLLC]

Great suggestions! I believe supco also makes a fan puller too.

[@justyn5086]

It is 1 AM right now, but I am going to check in the morning if this is what happening to mine. Will it hurt the unit if I don’t fix it?

[@JoesGarageProductionsLLC]

Should be fine as long as the blade doesn't separate from the hub completely.

[@Manix81]

Thanks for the help.

[@yolandaspencer2509]

That was so helpful. Unfortunately I have to call a hvac repair person. I hope they are fair

[@harryjames5904]

Yep, see that sheet metal blade they embossed so it wouldn't cavitate. They use to be solid thicker metal. with no embossing. The older rectangular Rheem was the easiest to work on. The compressor was not under the fan

[@JoesGarageProductionsLLC]

Yeah you mean the rheem classic from the early to mid 2000s right? There are still quite a few of those chugging along happily in my neighborhood here. Pretty amazing when you consider in South Florida the AC runs pretty much year round. I'm starting to see a lot of these newer rheems that look like mine. As far as I can tell they seem to be holding up well but I do know quite a few people that had condenser fan motor failures, some multiple failures like mine.

[@juliemeredith2735]

Thank you soooo very Much!

[@Hotpcmman1]

I just had a new Trane 5ton XR installed a couple weeks ago and hearing the same lound bang noise during shutdown. I just hope the bang noise is from the fan blade which would be a simple fix. I will not allow anyone tell me it is normal after spending $5K on one of the best a/c units on the market these days per the installer. There is no way TRANE Engineering would allow this noise to be released into production.

[@JoesGarageProductionsLLC]

Agreed. This problem is far more common than people realize

[@AdrianR84]

We had a new Goodman unit installed a couple of months ago and we’re having the same issue. Our HVAC guy says there’s nothing wrong with it.

[@mariomilan5910]

I have the same issue with my one year old 5 ton Trane.Did you end up fixing it??.

[@hroman5]

great video!

[@andrewhillman9632]

I have one condenser with the same noise, I'll check for this same issue

[@kadeemhall6602]

Quick spot tack will

[@donaldvargo4909]

Thanks!

[@wonderfulcreations3139]

Really, that's the solution?

[@texasnas50]

mine is the same issue. i will check the fan. I need a welder.

[@kayjay7201]

Thank you

[@jrich1209]

u r my hero

[@jrich1209]

// did we try n weld later?!

[@JoesGarageProductionsLLC]

@@jrich1209 no, I didn't try. Welding galvanized can be very dangerous and wasn't worth the risk

[@davemaldo07]

Nice

[@nh1702]

Mine makes that same noise year round even when not in use

[@egypt4000]

This is my current issue. Maintenance came and gave me a load of 'its normal' BS.. guess he thinks im stupid and tell me anything to rid of me.. i said ill find out the truth tonight on youtube buddy.. And here i am. Found out the truth. Thanks

[@JoesGarageProductionsLLC]

I had this same issue happen to my other AC, and staking the hub in place with a chisel and a hammer seemed to solve it. That was a couple of months ago and so far so good.

[@xcalibre222]

As soon as I saw the problem I thought to myself, ( Hey weld tack the hub to the fan).

[@hillcrinton1416]

Fix it for spare parts...

[@ryanrivera1224]

I bet this pisses of hvac techs 😂

[@hvacjay3201]

Scrap it. If you weld it, it’s gonna be off balance and destroy your motor.

[@Wigwhom86]

Eh that close to the center, a tack weld isn’t going to hurt anything

[@redfaman]

Weld the old fan then optest it

[@mr.fredricklawngtawnghedav5094]

Waste of time and resources to fix old fan..... Unless the new one does the same thing. In which case I would return it for a refund, and weld , and balance the old one.

[@ice4278]

Fix it

[@GoBart454]

I would weld it. But thats me.

[@leroybarksdale3129]

Welding be off balance trash it