How to Test an HVAC Motor Capacitor | Spec. Sense
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- čas přidán 10. 07. 2024
- Is your furnace or AC motor not starting? This video shows how to safely discharge and test a capacitor with a multimeter. Capacitors are used to energize the start winding in single phase motors. Capacitors can weaken or fail over time which can prevent the motor from running properly. Capacitor testing can help determine if the capacitor still operates within its rated capacitance.
In this episode of Spec. Sense, you'll also learn how capacitors work, what the capacitor ratings mean (MFD / uF) and the differences between a start capacitor, run capacitor, and dual run capacitor.
Buy Run Capacitors: www.amresupply.com/catalog/Ca...
Buy Start Capacitors: www.amresupply.com/catalog/Ca...
Need a replacement motor? Find a match here: www.amresupply.com/catalog/Mo...
More videos:
The Complete Guide to Matching a Motor: • How to Match an HVAC M...
How Do HVAC Motors Work?: • How Do Electric Motors...
How to Replace a Furnace Motor: • Furnace Motor & Capaci...
Furnace Troubleshooting Playlist: • Furnace Troubleshootin...
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00:00 Intro
01:11 Capacitor Ratings
02:40 Capacitor Discharging
03:29 Capacitor Testing
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AMRE Supply provides homeowners, service contractors, and property management with the parts and knowledge needed to get the best performance out of any property. Stocking the largest selection of appliance parts, heating, plumbing, lighting, and janitorial supplies, AMRE ships almost anywhere in Canada within 24 - 48 hours. Expert help is available online, over the phone or in person at one of the many locations across Canada.
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*Update* Just to clarify at 4:07 the multimeter should be set to capacitance for testing the dual run capacitor. Unfortunately this shot can not be fixed without deleting and re-uploading the video. Overall these errors do happen when filming multiple takes, combining the multimeter shots with the actions, sometimes the wrong shot is placed in the timeline.
@@cafemolido5459 thank you for watching. Once videos have been uploaded, they can not be updated or altered without losing all views, comments and interactions and many other people have found this video helpful even with that section of the video in. If we reuploaded this video it would like never reach the same visibility in the CZcams / Google search which means less people would be helped by this content. This pinned post is a way of communicating any updates so that people are aware of this detail.
Why do you still get the correct reading in mF though when you are on ohms…
@@p__jay It's a result of how we edit the videos. On the multimeter, sometimes the value jumps around and sometimes we get reflections in the screen. In some cases we cut out the screen and paste it to another shot that has a better hand motion. In this example the screen was used from a capactance testing shot and the multimeter itself was used from the resistance shot (testing for a short).
Simple, clear and to the point, this is how I learn. Thank you and subscribed.
Thank you Mark, I think you'll find some of our other videos helpful as well!
What a fantastic video! Very well done and informative. Thank you.
Thank you Darren! It means a lot to our video team to get feedback like this!
Thanks for taking the time to make all these great, informative videos! Very simplified and explained well.
You're welcome Michael, we're glad that you're finding the videos helpful!
Very nice. Exactly what I needed to know. Thank you!
You're welcome Merescat, we're glad you found it helpful!
Fantastic walk thru. Very informative.
Thank you! We're very glad you found it helpful!
Thank you for such a clear and simple explanation of capacitor testing
You're welcome Nate, we're just happy to help!
This is what the internet should be about ,
Helping each other . Thank you
You're welcome! We put a lot of effort into our videos so its great to hear that its helping people. We've got many more on our channel including furnaces, water heaters and we recently released a series on oven an stove repairs. czcams.com/play/PLCo9SMjkdWBysYYCcg5xQLiVh_cW0JQvt.html Refrigerators are next!
I will never leave this channel the way it explains...good
Thank you, we're just happy to share some good info!
Very helpful. I watch a few cannot fathom. Yours so simple and easy. U are a great tutor! Thanks.
You're welcome, we're just happy to help!
This was such a clear and concise video. It helped to get a basic understanding of the workings within a Capacitor in a simple way. Ended up finding the Capacitor had grounded out causing it to fail in my Coffee Grinder (Industrial). As this was an older unit the wire coating had become brittle, exposing bare wires in several places. Replaed all the wires with two new Capacitors and it's good as new!! Thanks so much.
You're welcome, we're glad that you found the video clear and easy to follow!
Thank you so much for this great video! I am trying to find out if the capacitor of my laundry center is still good or not, and this video is exactly what I was looking for. Thanks again and regards from Mexico City.
You're welcome, we're just happy to help. We are working on more appliance troubleshooting videos. We just finished a series on oven and stoves: czcams.com/play/PLCo9SMjkdWBysYYCcg5xQLiVh_cW0JQvt.html and we're currently working on Refrigerators. Washing machines are on the list as well!
Thank you. Very educative regards
You're welcome Sesha, we're glad you found the video informative!
Excellent ! I regret I did not see this video 2 years ago when I was told during my HAVC inspection that my capacitor needed to be replaced and I had to pay $228 for this operation. A few days ago, during my annual inspection, the technician told me that the capacitor needed to be replaced again ! the price tag was now $479 !! Holly cow! When i asked him the reason the price went from $228 to $479, he just told me that the prices of capacitors have been going through the roof. My guts were telling me it was fishy. Then, I found this video. I bought a multimeter online and I checked the capacitor, and yes, it was weak (4.6 uf instead of 6 uf). So, I did some research and found an online store that sell the exact same capacitors. The price shocked me: only $1.98 the capacitor ! I ordered it and replaced the weak capacitor with the new one by myself, after finding a video explaining how to do it, and it works perfectly! So, I just saved $477. Incredible !!!
Thank you for sharing your experience! We're just happy that people are finding these videos helpful, especially when it helps them save a few dollars.
@@AmreSupply well, it is not just a few dollars but a lot ! So, thank you very much for it.
This was the best instructional video for the subject matter.
Thank you Rafael! We're just happy to help!
Very nice and informative video and interesting. Would like to see more good videos like this, they are hard to find sometimes. I learned a lot, thank you.
Thank you Pat, we put a lot of effort into making our videos informative and easy to follow and we've got many more videos on our channel. We just released a series on oven and stove troubleshooting czcams.com/play/PLCo9SMjkdWBysYYCcg5xQLiVh_cW0JQvt.html as well we are currently working on a series on refrigerators.
Thank you for the video. It helped me out!
You're welcome, we're just happy to help!
I'm saying to myself what an amazing video, let's subscribe, but then I remembered I've already registered last week because of another excellent explanation on a different subject 🤯
We're just glad that you keep finding our videos helpful! If you're curious we have a "how it works" playlist which many people seem to find informative. It has the same sorts of detailed graphics as this: czcams.com/play/PLCo9SMjkdWBxWwrWCmzvRMSi2kLo9bGdp.html
Very professional. Good stuff
Thank you!
Very helpful. Thank you. 👍
You're welcome, we're just happy to share some good information!
excellent video. I think my Run cap for my ac just went out and its been a while since I checked one. Great refresher.
Thank you Bradley, we're just happy to help!
Thanks! Don't stress about the error at 4:07 I just assumed it was set the same as before to capacitance. Having to go back and see that it was set on Ohms only strengthens my understanding of the process.
Thank you, we're glad that it didn't retract from the overall video. That is why we try to teach the underlying principles.
I'll be testing a dual run capacitor that's part of my home Coleman HVAC; a packaged unit that's mounted on the roof. Not sure how much of a pain in the ass it will be to access the capacitor but once I do, this your video will most definitely come in handy. Thanks!
Thanks, we're glad you found the video helpful! Best of luck on the repair!
Very informative thanks for sharing
You're welcome, we're just happy to help!
Very effective and helpful tutorial video.
Thank you, we're just happy to share some good information!
I agree with Darren C - what a really great video: clear, complete, and still only five minutes in length. I have subscribed.
Thank you Michael! Its great to see comments like this. We try to keep all of our videos clear to the point with additional graphics when needed! Cheers!
Awesome video, 10 out of 10 for straight to the point valuable info
Thank you, we're just happy to share some good info!
Very well done great video
Thank you!
This video is so interesting thank you
You're welcome Noe! We're glad you found the video informative!
Your voice is perfect for voice over.very cool and calm. Nice demonstration.
Thank you, we're just happy to share some quality information!
These Canadians out here saving my ass again! Much love from your friends down south!
You're welcome Alan, we're just happy to help out in what small way we can!
Amazing video!
Thank you, we're just happy to share some good info!
Great video thank you
You're welcome, we're glad you found it helpful!
I really enjoyed it
Thank you, we are glad to hear it!
Thank you for that sharing sir.
You're welcome!
Great video man
Thank you Mike, we're glad that you found it helpful!
Very good video
Thank you! Our goal is to make all our videos clear and straight forward like this one!
Excellent explanation
Thank you, we're just happy to help!
Thank you. Best video. Ibsee Everything is perfect 👌
You're welcome, we're just happy to help!
Thanks from America.
You're welcome, we're just happy to help!
Thanks for the info although I know some of these. Keep up the good work 👍
Thanks! We're just glad to share some information! If you're interested we have many other videos including a whole "How it Works" playlist czcams.com/play/PLCo9SMjkdWBxWwrWCmzvRMSi2kLo9bGdp.html Cheers!
Very helpful, I learned a lot. Thanks for posting.
You're welcome! We're glad you found it helpful!
Very nice. Short to the point.
Thank you David, we're glad it was helpful!
thank you!!
You're welcome Alexander!
Awesome video you to best
Thank you! We're glad you liked the video!
💜❤️💙💚🧡🇿🇦 great video thank you sooo much you the best teacher
You are very welcome Nathi! We're glad that you found the video helpful!
Good video
Thank you!
Awesome Vance👍🛎《☆》I tested the 10mf Run Capacitor in my HVAC air handler. The meter showed 9.62mf which doesn't seem too bad. The short to ground test was a bit troubling. It showed alternating OL & 8.4 Megohms. I went ahead & ordered a new 10mf Capacitor. Thanks for the Clear concise lesson👍🛎New Sub here🖖😎☮
Thank you for sharing, we're just happy to have helped! Also happy to have another subscriber! If you're curious here's one of our favorite playlists that show "how it works": czcams.com/play/PLCo9SMjkdWBxWwrWCmzvRMSi2kLo9bGdp.html
Can you test capacitance while wired to the motor or does it have to be removed? I tested one and it had OL while wired, but then when I took it out, it gave a reading of 5.1 for a house fan motor capacitor. I think it should be 5.25 or 4.75 to be within 5%. Thanks!
Thank you for watching! Its best to test capacitors when isolated with the wires removed. Now if your capacitor is rated for 5 mf, then a reading of 5.1 is perfectly fine.
Great video thanks a lot
You're welcome, we're glad that you found it helpful!
Yes, it's really very helpful video, thanks once again
One more thing all our parts are getting ordered from Amre supply
@@anilksingh650 Thank you for your support!! All the best to you
Thank you Vance, and what does MFD mean when testing capacitors? Micro Farad Discharge rating, is that always printed on the spec label? Under MF? or MFD? And I didn't see anything about the furnance capacitors in the furnance videos wondering what the signs of a bad capacitor on a furnance is, I know swollen, not turning on blower motor or control board? Ok, I'm not remembering the details of the topic sorry too much to try to digest. HVAC capacitors. Thank you Sir.
Thanks for watching. MFD stands for Micro FaraD and is the the level of capacity in a capacitor.
If the capacitor fails then the motor might not start, or will not run efficiently depending on the model. If you are curious, the different motor types are explained here: czcams.com/video/vpspMVQQXRs/video.html
Why did you use ohm to test the dual capacitor with the common fan and herm?
Thanks for watching. We made a pin comment explaining this. At 4:07 the multimeter should be set to capacitance for testing the dual run capacitor. Unfortunately this shot can not be fixed without deleting and re-uploading the video. Overall these errors do happen when filming multiple takes, trying to get the best hand motion or the clearest shot we were combining the multimeter half of the screen with the action of testing with the probe. In this case the wrong shot is placed in the timeline which had the wrong setting showing on the multimeter.
Can a capacitor test for continuity? When it read on continuity, is the capacitor good or bad, not to groun but the two terminal
Thanks for watching. A capacitor is best tested by using the capacitance setting on a multimeter. Testing for continuity will tell you nothing useful about if a capacitor is good or needs to be replaced.
When there is only two wire to attach to the capacitor. Does it make difference which wire should go on which terminal?
Thanks for watching. A capacitor is not effected by polarity so it doesn't matter which of the two wires are connected to each terminal. The capacitor will still build and release a charge to help the motor start.
Is it possible my Trane 4TWX5042A1 heat pump doesn’t have a capacitor for the fan? There is a single 45uF capacitor (97F9646) and no other capacitor visible anywhere. The fan is GE ECM 230V AC. The cooling fan starts with a jerky movement and never really gets going.
Thanks for watching! If your motor is an ECM or Electronically Commutated Motor then it won't use a capacitor. ECM motors use a electronic controller to convert the AC voltage into DC. The controller then modulates the frequency to speed up or slow down the motor as needed. If you are having issues with the motor then its likely an issue with the electronic motor control.
Dude your beard is badass, thank you for the video
You're welcome, 'we're just happy to help!
This is so educational and informative. Our unit goes on and faults out prematurely (I think it's always code 33). The 'tech' wanted to swap the control board but also questioned the cap (though it looks good with no bulging). I saw that he was just throwing parts art it, and I can do that. I'll read the cap and think he did show that it was lower (then why didn't he change it?) but suggested the control board, and then maybe the cap. He even suggested if the cap was bad, it could damage the board. If the cap is outta range, might just replacing it suffice? Regardless, I think that'd be a better first step (if needed) than the swapping the board first. I'm an engineer and work on everything, including all appliances so I'm not just hacking here. Regarding your cap discharge screwdriver, same is true with microwaves, so I made a discharge tool with alligator clip and resistor.
Thanks for watching! We're glad that you found it informative! If the cap is out of range then you'll want to replace it as the blower fan will not work properly. A weak blower motor will likely trip the limit switch causing a shutdown. Now if your furnace starts and shuts off then it could be one of several problems. First find out what the 33 code is by referencing your manual. It will likely point to a particular stage in the furnace sequence rather than a part. This video outlines this in more detail: czcams.com/video/b0sAGt-1niU/video.html Hope this helps!
@@AmreSupply THANKS, I had watched that already. I had pulled pulled and cleaned the flame sensor. Our 33 suggests filter (which was cleaned) or limit switch, which I need to find. All is fine until about 4-5 deg below set point, then it stops with blinking light with 33 code. I'll check limit for continuity but it might be intermittent as you say. Might it be thermostat?
@@girohead The limit switch in your case would be the best place to start. Its a bi-metal switch with metal contacts that can warp overtime as the metal fatigues. This means that the temperature that it will open at can decrease as the switch wears out. This is harder to test or pinpoint as the switch will have continuity at room temperature. The switch is pretty in-expensive and would be a good thing to eliminate.
@@AmreSupply I'll certainly call you guys. I've not measured my 10uF capacitor yet, but if bad, what would that do?
@@AmreSupply I called and they needed a part number but aren't they the same for all Bryants? I also saw that they could be damaged if run and set frequently due to dirty filter (which started all this).
Question: Is that insulated screw driver just a normal screw driver with a rubber? Handle?
I bought electricians screwdrivers and they are covered with rubber or insulation with just the tip of the screw driver head being metal.
So if I tried to use the harbor freight electricians screw drivers I would'nt be touching metal to metal to discharge the capacitor? or can I use say for instance a harbor freight "normal" pitsburgh screw driver with all metal except to the handle which is rubber?
Thanks for watching. In this case, to discharge a capacitor the shaft of the screw driver has to be metal, and the handle will be insulated to ensure that the hands are protected from the discharge. Gloves are always recommended, and using a resistor to discharge a capacitor will always be the most safe when compared to a screwdriver.
Today I changed a 4 mf +-4% capacitor because on my multimeter it showed 3.42. Would you say the capacitor was going bad?
Thanks for watching. 3.42 mf is outside of the tolerance for that capacitor so it was likely going to create problems if you left the old one in the system.
On a run capacitor with rating 7.5 mfd what rating would be a bad capacitor? Example if 7.5 rating but get a 5.3 would it be bad?
Thanks for watching. Anything outside of a 5% difference to the rated value. So in this case anything lover than 7.1 or higher than 7.9.
What if it reads right when you first put it on but then climbs out of range? I didn't see this scenario in here?
Thanks for watching. When testing for capacitance, the multimeter is charging the capacitor in a sense. The values will might take a moment to measure but it shouldn't climb out of range. If it's outside of the range, then replace the capacitor.
I have a start capacitor with a reading of 244mfd and a rating of 233-280mfd, therefore within range but on the low side, should I change it anyway since motor seems to just hum and not start?
Thanks for watching. That is close to the 5% tolerance but for how inexpensive the capacitor is compared to the motor & control board it is a good thing to eliminate as a potential source of the problem.
It's also good to check the wire connectors for any corrosion, and to make sure that all the connections are secure.
If your motor is a condenser motor it might also have a start device or relay. A faulty relay can also prevent the motor from starting.
@@AmreSupply thank you! I ll go ahead and replace the capacitor; the motor is in a washer, it is 2 speed, the regular washing speed works, but the spin cycle only causes the motor to hum and emit a burning smell, thus my confusion, how can the low speed work but not the high speed, perhaps each speed has it s own set of windings, and the high speed windings have a short?
So would a reading of 6.8 be too low for a 7.5 uf 370vac run capacitor
Hi Dustin, thank you for watching. Generally for most capacitors the acceptable variance is 5 - 10%, so at 6.8 its a little on the lower side and could create some issues.
Can you tell me why sometimes my blower motor will come on and sometimes it just hums? When it just hums, I get a slight bumming smell. Also, when it hums and I turn the electric switch off then back on, it usually works again. Can you tell me what that might be? Capacitor? Or do I need to get a whole new blower motor?
Hi Jennifer thank you for watching. If you test the capacitor and its below its rated values then you'll need to replace it. This is a inexpensive place to start and is usually worth trying. If the capacitor is good then its likely a problem with the motor Overtime the motor bearings can wear down making it harder to turn. You can try to turn the blower wheel by hand and see if its smooth. If turning feels restricted in any way then you'll want to replace the motor. The slight burning smell is likely the motor overheating when its just stuck in place.
AMRE Supply Thanks for the advice. Can you tell me what motor and capacitor I’d need for this furnace and where I’d get both?
Carrier Gas Furnace
Model# 58PAV135-16120 58PAV135-20
Serial#. 3096A07906
@@jenniferappleton4944 We sell a wide range of motors and capacitors here at AMRE Supply. If you call our Customer Care Center 1-800-661-9891 and provide that information we can narrow down the replacement parts for you. As well you can email directly at customercare@amresupply.com
Can I use my multimeter to test the cap in my furnace, mine says 1.5volts under the capacitance setting
Thank you for watching. You can test your furnace motor capacitor but it should not show voltage when testing capacitance. The voltage rating on the side refers to the maximum voltage that it can handle. The capacitors charge will be in microfarads (uf).
@@AmreSupply thanks for the reply , I should get a good reading from my multimeter then? I'll be shopping at my local amre supply because of this service!
@@supras7 Thank you for your support! Test and reference on the microfarad reading on the side of the multimeter. The capacitor should be within 5% - 10% of that reading. If it is out of that range, then it's best to install a new capacitor. If you need a new capacitor you can match one from the selection here: www.amresupply.com/catalog/Accessories-635291
If the reading is low like the one on this video at the 4:00 minute mark, will the motor still run or not or does the motor run but not as fast?
Thanks for watching. If the capacitance is really low then the motor might not start. If the motor does start it will effect the efficiency.
@@AmreSupply I've noticed that my blower is blowing around 20% less than before from the vents and less suction from the intake vent/filter. I don't hear or noticed an indication of motor bearing wear. I ordered a new capacitor but haven't gotten it yet.
@@squidusn71 Thanks for the update. Was that a sudden change or is it something that has dropped off over time? Also is there anything restricting ariflow? Did you recently put a furnace filter with a higher MERV rating in? These can change the dynamics within the system.
@@AmreSupply Happened after I changed the gas valve. The filter is new and it is a low restriction filter. I don't have a meter that will measure capacitance at the moment.
Genius
Thanks you!
0:15 capacitors in single phase motors incl furnace blowers, AC fans, compressors and pumps
1:22 maximum voltage that the capacitor can be exposed
Thanks for watching!
Can I replace my gas furnace fan motor 208-230 voltage, 7.5 MFD with a fan motor that is 208-230 voltage and 10MFD?
Thanks for watching. When installing a replacement motor, you'll have to match HP and amp rating. If the new motor is rated for a different capacitor, then you'll need to install a compatible capacitor with the new motor as well. This video explains some of this in detail: czcams.com/video/TF3QtXWd8s0/video.html
@@AmreSupply Thanks for the information
@@dianavangaalen2190 You're very welcome!
Don't understand how to set my Plusivo cheap multi meter to do this test.
Thanks for watching. A basic multimeter might not have this function included and will likely just have several resistance testing ranges, voltage and amperage.
2:25 This is my AC start capacitor.
How far out of spec (capacitor) would one
typically be, to the point where the compressor may have
trouble starting or just not start?
in terms of %, 'BALLPARK' I realize there are many different
ac sizes and models.
Thanks for watching. Generally anything outside of a 5% difference of the rated value can create issues.
@@AmreSupply
How far out of spec (capacitor) would one
typically be, to the point where the compressor won't start?
@@bikersoncall 10% or more. When troubleshooting you'd want to check the compressor windings for resistance / continuity, as well as check any overload protection devices or relays.
@@AmreSupply Thanks.
@@bikersoncall You're welcome
Mine passed the resistance and I was still having issues with the motor stopping. When I checked cap. I found it to be way out of range. Wish I found your video earlier
Thanks for watching, we're glad that the video helped you narrow down the problem!
I have the same capacitor with the SAME logo, but none of the numbers on the one in this video match the format printed on my capacitor, wtf.
Thanks for watching. Is there a MFD or voltage rating at all on your capacitor?
If there is a part number you can always search it and use it as a reference. You might be able to pull up all the info digitally.
😍😍😍😍😍
Thanks for watching!
3:29 How to test a capacitor. Simple and easy
Thanks for watching, we're glad that you found it helpful!
Could be remade into 3min video
Thanks you for your feedback. We will likely keep the video as is. Since not everyone has the same knowledge base we try to always include the how and the why, to help give context to the test or repair. We have added chapters to help people navigate quickly so they can skip to the section that they want to watch.
My good jeebus you're a handsome man
Thank you!
ac only hums/buzz's, then shuts down, no fan running on outside unit. capacitor maybe?
Thanks for watching. Yes the hum is a good indicator that the motor is receiving power but isn't starting. It would be best to test the capacitor.
Shorting out the capacitor is bad practice and will harm the capacitor. Discharge it through a 25W ceramic resistor or via your multimeter.
Thanks for watching. You are right that using a resistor or dedicated discharging tool will be best.
If you have ever experienced a capacitor explode, even a small one, you would not use a screwdriver to discharge. Instead, use a bleeder resistor. (Only take one explosion to change your mind) !!
Thanks for watching. You are completely right that a bleed resistor is the safest and most controlled way of discharging a capacitor. You will however get HVAC techs who still use screwdrivers to do this for work on lower voltage residential capacitors such as those in a furnace blower motor.
Went to school Northern Alberta institute of technology ,lol this how the instructor discharge caps.@AmreSupply
I have a regular multimeter
Thanks for watching. Does it have a capacitance setting?
I didn't know keanu reeves could repair appliances.
Thanks for watching.
At 3:43 Captain Obvious teaches us to test the capacitor by using a meter that tests capacitance. "Go buy expensive meter, apply probes." Also Captain Obvious: Ignore we are measuring Ohms because pressing upload again is hard.
Thanks for watching. To test a capacitor, testing *capacitance* is necessary to make sure that it's within the acceptable range. As there are many multimeters that can test capacitance that that are only $30 so you don't need an expensive multimeter to do this test.
Dude acts like a robot 🤖
Thanks for watching. Overall we script these videos in a way that is clear and straight forward so no extra words etc. As well we try to do the motions slow so people can follow along. We hope you found it helpful.
@@AmreSupply Thanks. I understood it was meant to be that way. It was helpful.
This video is not helpful unless you have a capacitor tester.
Thanks for watching. Yes you are right that to test for capacitance, you'll need a multimeter with the capacitance testing function.
Try licking it might suit you better