Central A/C Compressor Won't Start Up(Stuck/Momentary Hum )

[Music] hey gang welcome back to another electronic form or video I received a call from a very good friend of mine telling me that his a/c system wasn't working that the compressor every morning or every other morning he would have to turn the breaker on to reset it it was tripping the breaker every time the compressor would start up and right now the unit is not cooling at all all you hear is the cooling fan going on the unit so what I'm going to do in this video is troubleshoot this unit right here the power supply is in that breaker panel right over there so first I'm going to remove this panel and make sure the voltage is sufficient to rule out that as being a problem why the compressor is growing too much current okay first thing I'm going to check the incoming AC voltage and we're looking pretty good each leg around 120 1.3 volts so I know the sufficient power going to the unit it's not a low voltage problem now the next thing I'm going to do because the compressor every so often I'm here crying come on that's an indication to me that the compressor may be stuck now this is a seven year old unit up until about a month ago there was no problems and there was happened every morning when this system would turn on it would trip the breaker and usually when that happens that's an indication of excessive current being drawn by the compressor so I want to find out why the compressor is drawing at the parent so I'm going to do is take a closer look at the compressor and the connections I'm also going to check this capacitor to make sure and you just heard it come came on and it clicked off an overloaded and that's an indication that compressor is sticking going to check the value of this capacitor to make sure that the value is what it's supposed to think if the value is what it's supposed to be and the professor of termini look good there's no corrosion everything's like this right what I'm going to end up doing is installing a hard start tip but a hard start to it is is another capacitor in parallel with this one right here and it's only going to be used when the compressor starts up you give it the extra starting torque that turns down a little bit late so she started and once it starts up it's removed from the circuit and only this capacitor is left there so let me turn the power up and take a closer look at a few of these things okay with the power disconnected from this condensing unit the first thing I want to do is identify the common terminal this is a dual capacitor one side of its use for the fan on top and the other side is used for the compressor so I want to identify the one that says HP RM which stands for hermetically sealed compressor and the terminal that says common take my capacitor discharge tool this is nothing more than a 10 watt or actually 11 watt 20 K ohm resistor you take one end touch it to chassis ground and then you're going to touch it to each one of the terminals for a few seconds go to each one each one of them and then once that's done I'm going to go between the terminals [Applause] okay let's go between these terminals and then I'm going to short the terminals to make sure that's totally no charge at all all right so I just lifted the red one up but let's go between both good so now I know it's safe to touch now I'm going to push this back down now that this has been completely discharged where I'm going to do is remove the capacitor from the unit because I want to see what the ratings are on the capacitor and then I can show you on top with the markings our compressor common and fan so the red right here pull that out and the purple go on the common the brown goes to the fan and pull it off there we go and then we have the yellow that goes to the compressor so let me undo that and remove this from the unit okay this is the capacitor out of the machine right here you can see this fan right there it says H erm that's the compressor and over here is a looks like a letter C it's hard to see and that's your comment so I want to test the compressor between here the common and herm and I want to check the fan and make sure the readings match exactly or very close to 70 microfarads for the compressor and five microfarads for the fan if the readings don't match that's going to explain why the compressor is not starting up and it's also going to explain why the compressors been having a lot harder time starting in the morning resulting in the breaker tripping so let's check this out if it is the problem we're going to end up swapping this out and then the compressor should come right on so let's take a look at the readings on this okay digital multimeter is on the micro farad setting I'm now going to check the capacitor between the common and the fan first let's see what kind of a reading we get if it's close to five that's a little lower than five that's about 20% off all right so that's probably okay for the fan but still not good now let's go between the common and the compressor terminal and let's see what that one is well that is not good baby we got point 1 2 5 micro farad and that's supposed to be coming in right around 70 let's try that again yep this is looking like the problem why the compressor is not starting up okay let me put in another one and let's give it a try okay right here's the new capacitor went and picked this up now over the past two months like I said it was tripping intermittently when the unit was start up so that was a sign that the capacitance on this side of this capacitor was getting more and more open until the point where it was so low that the compressor would no longer start now if you don't have a digital meter that measures capacitance to give you a really accurate reading of the capacitor then what you could do is you could put this to a low range first so I go over here there's ohms then select the range select a low one right there and you want to go between the terminals you should not get any reading if this gives you a reading on the lowest range that's going to indicate that they could pass it or shorted and you want to check between a common and the compressor terminal and the common and the fan once that's done you're going to switch to the highest range which is going to be mega ohm right there check between each terminal right here and the can body and you should have no movement on that meter if you do you're going to have to replace the capacitor okay let me reinstall this in the unit and let's see if it corrects the problem hopefully it does if it doesn't then I'm going to have to show you what to do next now can't go too high otherwise I think the wire was yeah these are short so let's go let's try right tighten that down securely okay now I know why this cardboard was here yep keep it away from the contactor I see the yellow goes to the compressor good and the brown over here goes to the green which is the fan a little Tamar that actually I don't know why they didn't believe pull a bit more lawyer out of this bunch oh I see this red ones too short alright whatever idiot did this put a short red wiring because this should been longer and then this woulda been higher but it's been like that seven years it should be fine here let's take this red one clip it right is it this way sprite better that way that's all right tight make sure this one's on push this down just a hair that's that place not rubbing against the can okay now the capacitor is in if you notice right over here this wire is not in good condition so I'm going to pull off the yellow one and this one's been overheated so I'm going to pop that one out clean it probably throw a new connector on the end and put it back together alright here is the old connector that I cut off not in good shape overheated okay here's the new end very nice I clean the blade that the screwdriver scraped it nice and clean let me slide this back on all right that's a very nice connection now okay let me power this back up turn on the system and see if it works now 240 volts at the condensing unit going to go inside and turn on the system [Music] and we are back in actually now the homeowner knew absolutely nothing about a/c systems called up a dishonest repairmen he could have very easily told you that your compressor was faulty and talk you into purchasing a whole new condensing unit that's why you need to know how to test these things now if this did not make the compressor turn on then I would have left this in place I would have lifted this off the top and disconnected the wires to the condenser fan take all the power off of the fan and when I turn on the power to the unit I'd be hitting the top of the compressor with a rubber mallet trying to free it up and usually that does the trick but if your compressor starts to stick like that then you're going to want to make sure the value of the capacitor is good make sure all the terminals are very good then that burns up and corroded like the one I just replace here be sure to check the one on the compressor itself and if everything looks good you're definitely going to want to add a hard start kit all it is is another capacitor that's going to be connected in parallel with the common and the H erm terminal it's gonna be in circuit only momentarily when the compressor starts up to give it more starting torque and then it's going to be removed from the circuit leaving only that run capacitor powered up okay I hope you enjoyed this video if you did be sure to ray that thumbs up subscribe and post links to this video on other websites and blogs also be sure to check out my video playlists as well thank you very much for watching

Channel: electronicsNmore

Views: 348,931

Keywords: Central A/C Compressor Won't Start Up(Stuck/Momentary Hum ), How to fix your A/C, how to fix your air conditioner, house not cooling, step by step AC repair, how to repair your central A/C, split system air conditioner repair, central air compressor stuck, central air compressor not working, central A/C compressor repair, how to test an A/C capacitor, troubleshooting your A/C, electronicsnmore, how to free up a stuck compressor, A/C compressor won't start, lawyer, dIY A/C repair

Id: B8ealqmdlIU

Length: 12min 16sec (736 seconds)

Published: Sun Sep 09 2018