Is Your A/C Unit About To Die? This Tool Doesn't Lie

[@props-model-shop]

Just happened to my neighbor. Bad Cap caused unit Fan to stop working. Compressor goes into Thermal lock. He calls the AC repair man. The AC man tells him the Compressor is shot and that he needed a whole new systen at $22k.... I told him to wait for the motor to cool down and we replaced the Cap. All is working well now.

[@whochecksthis]

JEEEEZ! $22K? What did they quote him? A 5 ton variable output inverter heat pump? Hat is a massive price.

[@ttch2911]

If there is a delay circuit within the compressor, that might be the culprit that cause the compressor to go into a thermal lock. Mine happened as the delay circuit cause the compressor to start and stop a few times in a row and cause the compressor to overhead. Also Goodman compressors are junk.

[@TheQman69]

$22k?! We just had two new AC units and a new gas heater HVAC assembly installed on our 2500 sq ft 3 story plus basement house where the 3rd story has a separate blower and compressor than the 1st/2nd story and it didn't cost us that much. We paid almost half that much .. $12K and that's in northern VA (Loudon County) where the prices tend to be higher than the rest of the country too. I can now turn only the upstairs AC on at bedtime and not worry about wasting energy to cool the basement and 1st floor. This first month alone is already a massive improvement over last summer as we dealt with 90+ degree bedrooms on the 3rd story. It has even helped with our basement humidity too. We haven't had to use the dehumidifier once yet.

[@whochecksthis]

@@ttch2911 not all Goodman compressors are junk, but, yeah… those cheap rotary ones are… window unit level quality… Every motor I have ever worked on has a thermal overload switch that opens the common winding keeping the motor off until it cools down. I usually try running water on them to cool em down quicker, but I always tell customer it may need 24 hours to reset,so we can try and run it. Then determine WHY it overheated.

[@props-model-shop]

@@whochecksthis $22k would have been the cost if he had chose to use their financing for how many years to pay off... for a 3ton straight cool unit.

[@elBusDriverKC]

You want to pull ALL your wires off first, then test. There's a chance that the MEGGER could be checking windings all the way back in your system. Even if the wires are disconnected on the other end, you don't want to be checking the insulation against wires hanging out of the compressor. Also, it's best to sand back the copper pipe on the compressor and use that as your ground.

[@AbNomal621]

In fact, the reason for the changing value is capacitance most of which is NOT in the winding.

[@knife_knut]

Correct!

[@kirkjohnson6638]

I was about to comment the same. If the black lead of the megohmmeter is connected to a bad ground, you may get a good (high) resistance reading but actually have poor (low) insulation resistance between coils and the case of the compressor. So definitely, disconnect all three leads (noting which color goes where) and then test between each terminal and a clean spot (lightly sanded) on the refrigerant tubing coming out of the compressor.

[@Calliber50]

And you never want to megger a variable frequency drive or soft starter unless the manufacturer says it's ok. There can be circuits inside the VFD or soft starter that can't take a high voltage DC backfeed. Also before using your megger short the leads together and verify you read a short circuit. I've been on numerous jobs where the leads are broken internally or connections are corroded or damaged inside the megger so everything they test reads good. Even scarier is when the leads to your voltmeter fail and it tells you a circuit is de-energized when it's actually live. So get in the habit of testing known sources and circuits before testing the unknown.

[@destronger5313]

This KZbinr seems to half ass things. Yes, all the wires need to be disconnected. This tool also can check motors.

[@frankl1955]

I did my first job in 82. Sent the wife for a 6 pack of beer and it was WARM. She said the little store down the street had the cooler go out. I had just graduated the Weat Side Institute of Technology for A/C but the owner told me not to bother 2 different companies condemned the compressor... It was a sticky current start relay

[@mikeglasgow9618]

I helped a friends mother. He told me at work that it was the original unit to her home. When I got there it was a Chrysler Airtemp . Built in 1964. Had a bad contactor. Replaced, cleaned outdoor coil , lubricated outdoor condense fan, ,, STILL RUNNING TODAY.

[@Garth2011]

Yessiree, and now the weak point of that condenser is going to be the new contactor because its a new part that is not quality made like the rest of the condenser. I always tell folks to have a spare USA made capacitor and contactor on tap for the day they need one in the hot summer when HVAC is super busy and a few days before an appointment. At least you have a running start with the correct parts in the event their truck hasn't got what you need on that day. Yes, they usually have those on their truck but they do run out sometimes.

[@mikeglasgow9618]

@@Garth2011 hey Garth.... I am retired. I was just helping out a friend with a disabled mother. I did pick up a good contactor. Plus all the cleaning and lubrication. I have a 4 year degree in HVAC/R. Worked in the trade for 35 years. The last 20 years was industrial. Boilers, chillers , and DDC Controls. I've been retired for 7 years. Lol. I started out when heat load calcs were done Manuel D , on paper......now I'm telling my age.

[@OUFan2]

I put in several Fedders units back in the early 80's. It had a Rotary compressor back then. Didn't have scroll compressors then. The Rotary compressor lasted a long time in AC's with short line sets, but did not last very long in heat pumps with long line sets. The rotary compressor always had troubles oiling correctly. You were just lucky with the unit in this video. I quit selling Fedders very quickly because of their compressor failures. I went to selling Rheem in the early 70's and they were great systems, but they didn;t have heat pumps at that time, so that is the reason I tried Fedders. When Rheem came out with heat pumps, I never looked at a Fedders again, I was an Air Conditioning contractor from 1972 till 2016 and then retired.

[@Garth2011]

The main focus was if the condenser had a Copeland compressor, it was good.

[@westvalley411]

Thank you for your service!

[@kevinc8811]

I started in the trade in 77 and am still an HVAC contractor in Florida today. You’re right on point. 👍 It has to be close to 20 years since I’ve seen a Fedders unit here. We and everyone else in our area abandoned Fedders years ago for the reasons you mentioned. I’m very surprised to see people in the comments here giving them love. 😂

[@JackLucas-jh1eo]

You are the "Man." You are demystifying the ownership of a home a/c system. Thank you for your efforts!

[@bran-qt7ds]

I had THREE different ac companies tell me my 10-year-old compressor was shot and I needed a new system. Finally a friend of a friend came and looked at it and fixed it for less than $100 by simply replacing pressure switch. That was 10 years ago and it's still running fine today. Anyone else would have just believed them and paid for new system, especially after three different companies saying need new system. AC companies are worse than used car dealers!

[@ronaldd.1355]

Does it apply to splits? (Panasonic A/C inverter 9000btu)?

[@cheezeball6109]

@@ronaldd.1355 I think in general, many HVAC guys have no idea what they are doing, and have no diagnostic skills, thus just recommending a complete replacement.

[@sprockkets]

Um, you replaced the pressure switch? You recovered the refrigerant, didn't vent any, and then had your friend braze in a new switch, and of course vacuumed it out and put the refrigerent back in? For $100 bucks?

[@jonathanocegueda7848]

It was probably one of the pressure switches that you tie in to the gauge ports that was installed.

[@sprockkets]

@@jonathanocegueda7848 which would be interesting because those are usually put in for those who need to switch off a fan motor because they need the a/c to work in the winter for reasons. No residential unit would have this.

[@johneldorado]

I had an AC guy about 12 years ago tell me my unit sounded tired and it was probably time for a new one. Still running great after 12 years.

[@youtbe999]

Perhaps he was referring to his own wallet?

[@rickgarcia239]

Sounds like the tech was tired of making decent money legitimately & wanted to make the much bigger bucks being a criminal...

[@bikerbobcat]

I sound tired and need replacement too.

[@ramohino]

Well consider how much would of been saved if you went to a more efficient unit.

[@johneldorado]

@@ramohino It never would have paid for itself and I would probably replacing a 2nd unit considering how poorly made the "new" stuff is.

[@Larry-yk5nh]

The manual for the insulation tester recommends that all leads be removed from the compressor at time of test. I would think that in some cases this could be important as other components still in the circuit could cause the lower 100 mega ohm reading you saw on the Goodman. The little tester does seem like a good idea. The manual says it applies 500 volts to the circuit at very low current and this is what is needed to properly do a test like this. Thanks for your video.

[@N-M424]

I agree regarding removing all leads. Also, the ground location being on a clean /paint free part of the case rather some other remove location is important to not receive a false high resistance reading. In the case of the compressor, directly to copper line seems like a good location.

[@Gus11445]

HVAC technicians stopped using these a year or two ago as we found out they can do damage to your unit. There's literally no reason anyone should be using this device over simply using a meter to ohm out the windings.

[@mjgrebert]

@@Gus11445 If used incorrectly, the high voltage output from a megohm tester *could* damage your control equipment. But a megger test and ohm test are used for different purposes, depending on what you want to know. An ohmmeter checks that the windings still have a continuous low resistance current path for the normal flow of current, but a megger test will tell you if the insulation around the wires is failing. An ohmmeter can tell you of a problem AFTER a failure, and a megger can let you know of a problem BEFORE a failure.

[@shoretrade9516]

Don’t listen to this guy. Depending on the oil and the liquid in the bottom of the compressor, you can get false readings and you absolutely must take the wires off the compressor.

[@Monster-o1q]

This is so awesome! I'm 55 years old and grew up hearing my grandparents say "They don't make things like they used to". Now, about 45 years later I'm hearing a younger guy say that same saying about current products. Love your videos. The facial hair addition is cool too! Keep it up!

[@notme8121]

I think it's very kind of you to do what you do. Many people get ripped off by scammers and especially the older people in my neighborhood and I do automotive AC but I've learned a lot about home AC from you. Thank you

[@handlesR4TrackingU]

I just updated my central heat & ac unit It was a Fedder installed in 1972. Replaced system not because the compressor failed but the ac system developed micro leaks. 3 in the last 4 years in different areas. With the insane cost of R-22 to recharge a 5 ton system. I couldn't justify the cost. So replaced the whole unit with the help of your videos. The $ saved on utilities and installing it myself. It will have paid for itself in 3.5 years. Thank You for the help. I could not have done it without your videos. Keep up the great work.

[@jacklabloom635]

I know of one Lennox combo outdoor unit ( Air conditioner/ natural gas heat ) that is 35 years old and still working. My late father-in-law purchased the unit 35 years ago. He died in 2022 and a grandson purchased the house. The grandson had the unit serviced, ( coils cleaned, Freon checked, etc. ) that old Lennox unit is still working to this day. The newer units just do not last that long. I have purchased several AC, Heat pumps, over the years. I have three Lennox AC units that are 23 years old. I have purchased York, Trane, American Standard, and Heil units in the past for different houses. My latest purchase was a Heil Heat pump, three years ago. So far so good on it. Only got 13 years out of a 5 ton Trane Heat pump. Replaced the outdoor unit with an American Standard unit in 2017. So far so good on it. I don’t know which units are better than others, but a good HVAC guy makes a big difference. My experience has been that Lone Ranger type HVAC guys, or an HVAC guy who has one helper provide better results than HVAC technicians who work for large companies, who employ dozens of technicians. Those companies have to meet huge payrolls, whereas the one or two person HVAC company is under a lot less financial stress to meet payroll. A good HVAC person does not have to advertise to get all the business they can handle. I found a great HVAC guy back in 2003. He was just starting out on his own back then. I have since used him for all my new installs and all repairs. I told all my friends about him. He got so busy he had to hire a full-time helper. He has so much business, he can pick and choose his customers. He is honest, reliable, and always does excellent work. He never had to use paid advertising. Word of mouth is more powerful in growing a business than any type paid advertising.

[@Garth2011]

All true...most installations that last the longest and have the least troubles are systems installed by a good installer/tech. Many companies "hire out" installers to do the grunt work and it shows badly. Better off having a single HVAC guy do the work and take a couple of days (or more) to get things done correctly vs. a crew of grunt workers looking at their watch/cell phone every hour or so "We only have X amount of time left".

[@BlueSkies42]

So true. One of my best friends dad has one helper and doesn’t need to advertise because he gets so many referrals just word of mouth because he’s honest and does a good job

[@Dave-ei7kk]

I found an HVAC contractor like that to replace my system. He was the owner and had a technician (his brother in law) and a part time casual labor guy. I knew he was the right choice when he came out to bid the system and answered all my questions (I’m an engineer) and told me that he would be the guy installing it. Very happy with the results.

[@bigd3104]

Amen!! And instead of looking online for an AC repair company when needed, call a local HVAC parts supply business. Ask for recommendations for an independent HVAC contractor in your area. NOT one of the big name contractors!! Save yourself some SERIOUS money! The best repair guys won't have a big storefront, a fleet of shiny new service vehicles, crisp company uniforms, and a monthly quota to fill.

[@superspeeder]

Bad motor windings (checked with this meter) are only one of many things that can fail in a compressor. This only tells you if the insulation in the motor is good or not.

[@danielwolf2192]

Well said

[@phillipsusi1791]

And it would only do that if you disconnected the rest of the circuit from the compressor, which he didn't!

[@bikerbobcat]

Residential and Light Commercial HVAC guy here. Diagnosing a bad compressor is the VERY last thing for me because checking capacitors and contactors is just so easy. For only $90, that tool isn't a bad thing to have anyway. It's so easy to be honest. I'd rather be wrong than crooked. Get 3 opinions ANYWAY. Good video.

[@mark33545]

People dont do 3 opinions because these places charge so much to come out and check it out. This industry is out of control.

[@jmachjmach2003]

​@@mark33545 Now that's the God forsaken truth right there. They think their time is worth so much, but all they do with their free time is TikTok. Lol

[@monteglover4133]

@@mark33545 It’s expensive to put a truck on the street $100k to $200 k, a good techs need to be paid, insurance, book keeping, …. so how much is responsible?

[@inothome]

As long as compressor is functional, all three windings are connected internally. Testing terminal by terminal as shown is also testing whatever is connected on the other two terminals and then some. All three wires need to be removed and just testing one terminal to ground will test all windings. That tester is low current, but puts out 500VDC. So if there is something at the end of one of the still connected wires that can be damaged by high voltage, you just damaged it. Or if a fan motor is connected at the contactor with the compressor, you are also testing that fan motor and wiring. Which, if you get a bad reading and mis-diagnose the compressor bad, when in fact it was the condenser fan or wiring, yeah..... Not to mention, there are other things that can indicate a failing compressor. Doing an insulation resistance test is just one test.

[@jeremiahmiller7796]

Oh the best part about all of that is also scroll compressors due to the tolerances in which they are designed and where the refrigerant has migrated to in the system a good reading is still below the red bad marker on that tool. I can’t remember how low it is. I think it was like 5 mill ohms where that one bottoms out at 20 mil

[@inothome]

@@jeremiahmiller7796 The old rule of thumb was 1M Ohm per 1kV plus 1M Ohm, before insulation testers were measuring giga-ohms and now even tera-Ohms. So anything less than 1kV was always 2M Ohm. Now of course as insulation, materials and testers evolved you'll have specs in 100's of mega-ohms for low voltage and much higher for high voltage equipment. As always, best practice is to follow the manufacturer's spec. Like you mentioned.

[@tegra5971]

I agree… testing with any wires (=control circuit) connected could zap the control. You are doing an insulation test so everything has to be floating

[@bengordon7635]

how long are compressors rated to last ,, why do they not make the compressor easy to remove to install a new one like in a car ? why do you have to weld a new one in??????

[@inothome]

@@bengordon7635 They aren't hard to install, usually. Just need to solder the refrigerant lines, no welding, like most refrigerant lines are anyway. Cheaper, less materials and less chance for leaks when soldered.

[@Krazy_Shorts]

I have Williamson unit that was installed in 1988, and knock on wood, still running perfectly today in 2024. Just did routine maintenance on it, filters, and coil cleaning. You are right, they don't make em like they used to. I'd love to try this compressor test on mine.

[@kieffersheatingcoolingv2.03]

Copeland states in bulletin AE4-1294 that megohm readings as low as 0.5 megohms to ground are acceptable. Besides the fact that this makes a scroll difficult to successfully meg (essentially impossible with a tool like the Supco M500 because it only reads down to 20 Mohms)

[@sbukosky]

Yes. This kid is giving bad information.

[@pegleg402]

I came in here to say this. Ive witnessed a few sales techs in my time condemn perfectly good units using this megohmeter.

[@kevinc8811]

@@pegleg402Exactly my thought too. Megohmeters can be a valuable tool for diagnosing commercial and industrial equipment. But pretty much unnecessary and useless in residential applications. It wouldn’t surprise me if it’s used more often in residential applications for nefarious reasons.

[@Practicing_HVACR]

I agree, the information is well intentioned but incorrect. This meter by supco is worthless. I can’t imagine how much money has been wasted because of good compressors condemned by that meter.

[@ngoshawk1]

Fluke 1587 is what you really need to test insulation.

[@althouse2]

I live in an rv park in Az. Many of these Park Models have been here since before 1982. Many of the rv's still have the original carrier pancake 2.5 ton straight cool ac with 7.5 kw heat strips and Coleman Saguaro park model, and you'd be surprised as to how many are still rocking. Performing very well I might add. Some have new fan motors but many are still factory, when I do a performance check the run caps are still spot on, and many haven't even been serviced in yrs, I do many a coil clean and install a tri-dem 3ply filter to keep their ducts clean for many yrs to come I will be getting a mega ohm to further prove to my customers that their unit is still good and performing as it should, not one of my service buddies has ever told me about a mega ohm meter before. Glad I came across your video in upping my knowledge

[@onenikkione]

which rv park in Az?

[@The1313jeff]

I have a 10 12 sheer Coleman heat pump and it is going on 27 years old and still running fine!

[@pctatc66]

yeah but your electric cost must be through the roof. Id hate to pay that bill

[@The1313jeff]

@@pctatc66 No it runs about $70 to $90 dollars a month in the winter to heat my house and the air condition is even much less then that!

[@chompnormski]

“They don’t build them the way they used to”

[@The1313jeff]

@@chompnormski And the fact that I only paid $590 dollars for everything the Heat pump and the air handler and all the duck pipe is another story by it's self! I had to give a guy $250 to hook the pipes up and thermostat And I installed the pipe and air handler myself! And it is still running today It is hard to believe what they cost now!

[@johngatsby1473]

​@@The1313jeffthey really aren't that expensive at all if you buy them yourself and then have it installed. These clown ass contractors are marking the equipment up 7 to 10k and acting like they got you a good deal.

[@GreyRockOne]

Good info here! I've always been my family and neighbor mechanical and electrical handyman, cars, electronics, home appliances, you name it. I've done all my own HVAC work too. You just need a good attitude, patience, common sense and a mechanical aptitude. I always love to watch your videos for up to date info! Thanks!

[@wholeNwon]

In my case, I bought an AC textbook, read it, worked on my own systems, took the licensing exam, aced it and was no longer an HVAC "service" victim.

[@xaviercruz4763]

How much would an air conditioner at good price new or used cost for 1 acre of land or ~3000 square meters for a greenhouse? A unit that can lower temperatures to 2-3 Celsius or 41f

[@SilverSergeant]

Unplug all the wires before testing. This was not proper technique.

[@cincybeck]

I would completely isolate the compressor. And hook your ground to the component being tested. Testing like this it could be the compressor, the wires, the fan motor, the starting cap, or even the contactor.

[@damon20r]

It is checking the resistance between the windings and the ground. There technically should be no connection between the two when everything is perfect but when the coating on the wire in the winding starts to deteriorate it will begin to lose some of it's insulating capability and the resistance will begin to drop down from near infinite to lower values. That device is a ohm meter designed to measure extremely high resistances. At least that is how I believe it works.

[@MariosACandRefrigeration]

how many did he get wrong,testing like this.

[@inothome]

@@damon20r If you leave any leads on the compressor you are also testing whatever else is still connected to the compressor. Since the windings are all connected internally, you put 500V on the one terminal and it puts out 500V on the other two terminals and what ever is connected to them. So you are testing much more than the compressor and can even damage things with 500VDC.

[@damon20r]

@@inothome I agree, I would have completely isolated it as well to eliminate the possibility of one of those components feeding back to ground and giving a false condemnation. But there aren't any components in that circuit that are going to be harmed in any way.

[@cincybeck]

@@MariosACandRefrigeration @inothome Explained it better than I did. If you don't disconnect all the wires, the compressor windings are still connected to all the other components electrically, so if any of those have leakage it will show as a bad compressor when it might be something else in the circuit that is bad. Also if there is any electronics (control board/inverter) in the condenser unit they could be damaged by the megger.

[@brunonikodemski2420]

Totally agree. We had a local contractor try to sell us a whole new system, based on "you need compressor". We were suspicious since the lifetime on the compressor was only about 3000-hours. Got another reputable contractor (Rocky Mountain), and they diagnoses problem, fixed it, for only 80$-USD. Can't mention the scam shop, but sure would like to.

[@Charger1908]

I remember Fedders well one of my friends was a tech in the 60’s and told me that Fedders were very good. I do all my own work and actually I am a retired police officer and after retirement I went into plumbing and at times I helped the hvac techs so I learned a lot. I am an extremely adept mechanic and I have been for over 50 years. So now I guess I will do hvac when needed, I see I can already purchase a unit and have it sent right to my house. I’ve subscribed to your channel and we will see how it goes. Thanks!

[@hjc4604]

My Dad got a used 240 Volt Fedders window AC, probably 24,000 BTU from the company he worked for. He had an electrician friend run the electric and installed it in our living area/dining area window. It worked for probably 12 years until my brother bought them a central HVAC system. A 4 bedroom rancher with a full basement.

[@BartlettTFD]

I remember Fedders produced excellent window ac units back in the 50’s & 60’s They were made to last! What has happened to the quality we had back then?

[@Garth2011]

@@BartlettTFD They were very popular ! I purchased a new Fedders R22 condenser in 2010, hard to find since R22 units were no longer being made. The information label said made in China. Sad.

[@ttch2911]

You are checking the insulation level between the winding of the compressor and the ground using the ohmmeter. Higher resistance means better insulation to ground so less likely to short out. Insulation generally don't deteriorate unless the insulation material are not up to standard or compressor overheated numerous times causing the insulation to break down.

[@davep2115]

Dirty freon is definitely not going to break down winding insulation. Lol

[@josephgraham1065]

Agree

[@Garyganeu]

I used the same megohmeter for many years. Used it on motors as well as compressors. Always worked.

[@UtwoBed]

Fedders made the best A/C units on the planet. I still have a little 5K BTU window unit that's literally falling apart but still works.

[@Garth2011]

Take care of it...she's worth it.

[@markheaney]

They go on about recycling when all they should do is make things last. This is true for everything.

[@jugears1081]

In 1972 I saw a program on PBS titled "Planned Obsolescence". They are building them worse every year, intentionally. I am a mechanical engineer. I graduated in 1972.

[@spinb]

And they keep changing/outlawing the types of refrigerant. "For the environment," myass.

[@Shadow-7773]

@@jugears1081 So what are Homeowners to do? With all of the videos and other news about what is best! It seems there is no way out when buying a system, expecting it to last.

[@mediocreman2]

I got told I should get a new car when I went to get a quote on painting a fender. It's a 31 year old car that works fine. If people actually cared about the environment, they wouldn't discard things so easily.

[@AverageJoesracingteam]

Your channel is great! You are saving people tons of $. Wish there was a channel like this that could save people from terrible doctors

[@nohandsdan9353]

*Trick of the trade* run the blower fan while evacuating and pull shrader valves. Bigger hose does work. CRT are a must and purge slightly longer to be safe. As a home owner request a Manual J. If they look at you dumbfounded tell them to leave. A properly trained HVAC/R Company/Technician will provide you a report that verifies the system size they professionally recommend on your specific house features. Oversized cooling systems can lead to microbial growth in the home due to the system short cycling and not allowing the system run long enough to remove the moisture from the air. Bigger is never better in the HVAC/R world.

[@Garth2011]

Our neighbor a few decades back was sold a smaller BTU system because "it will save him electricity" as it won't cycle on and off as much. LOL. Every time we visited them in summer times it never cooled the place down enough.

[@livingstones1196]

It's always best to consult the manufacturer about their products just in case they have an explanation of these readings. Copeland states that a reading of between >5-20 Megohm is not reason to condemn their compressor. I always like to stick to the old agage: "ALWAYS, consult the manufaturer if not sure" or something like that. But I do agree that NOT pulling the required psia will positively reduce the life of the system. And I've seen far too many contractors rush this part (evac) and make-up some excuse why they can't pull the proper vacuum and end up charging the system without completely dehydrating. No wonder the systems are failing. I'm convinced older systems lasted over thirty plus years because the service technicians of the past did it right. That is what I believe is missing today.

[@OGThinkster]

I use a megger at work for large 3-phase motors but didnt think of using one to test a compressors health. Thanks for for the tip and being honest with people who typically get scammed for not having knowledge in something like this!

[@trevmint5615]

Why can't you use a multimeter?

[@WarrenAllely]

@@trevmint5615 What should a multimeter read for resistance?

[@mtnest1226]

Love that silver KZbin plaque in the background,your videos are a great help for people who are overwhelmed by the hvac technology and of course some not too honest contractors

[@edthelazyboy]

I feel like I have to be a HVAC technician myself as a homeowner because of all the scummy HVAC companies out there. I'm already replacing air filters, testing / replacing condensor unit capacitors, replacing contactors, checking compressor / fan run currents, cleaning coils, checking duct static pressures, and checking gas pressures myself. Everytime I call for a HVAC service, they want to replace my entire equipment because "it's on it's last legs". Yet, my equipment is still heating and cooling my home. Many years ago, my parents' AC wasn't really cooling so their HVAC tech just added more R22 and called it a day. They didn't even bother to check for leaks in a sealed system. Thanks to this video, I'm adding megometer checking to my toolbox now.

[@terrylarson7596]

There are a few independent HVAC mechanics that will inspect your system and advise you honestly. My buddy just got a new furnace because his combustion fan was bearing was dry and seizing up. I replaced my sisters combustion fan for $350.00 in parts. Some businesses are directed to sell HVAC systems, they will say stuff like " I could fix this but something else could go next week"

[@Garth2011]

Condensate fan. Yes, they usually go out due to the crap quality bearings these days. They might save $3 vs. use a quality one and put the $350 part cost on the customers.

[@jons2447]

Many "THANK YOU!"s to you , sir! Dave, you *ROCK!* I'm so glad I follow your channel because so many people are rotten crud, liars, cheats, & thieves. Your honesty and character are a testament to you and your parents. May you be blessed for following our Creator's guidance. I've noticed that you try to help people protect themselves from evil ones. I commend you for your efforts & wish you the best. Have a GREAT day, Neighbor!

[@markelliott7917]

A meggar should be used on an isolated piece of equipment. If not, you are measuring the resistance to ground of whatever the other wires are connected to as well as the compressor. Also when using a meggar, it is actually measuring current flow, the lower the current the higher the resistance. The increasing readings are totally normal. They are normal because the circuit is acting like a capacitor, once the circuit is is charged , then can the resistance be determined. On the safety side the system will be "charged" after measurement. Be sure to short/discharge the tested circuit to ground before touching!

[@SilverSergeant]

Agree. Should have totally isolated the compressor.

[@SmooveBee1]

Trane SEER 10, two of them, THIRTY YEARS OLD here in Georgia; I can meg it out one day, if needed, but not needed right now; i have tested the temp in and out, pressure-checked it (I am just a homeowner), and calculated SUPERHEAT and SUB-COOLING both using temps from the Evaporator; these were each manufactured in 1994 and still running every year here in GA; I clean the condensers each year with Blue Dawn and lots of water; i don't cover the outdoor units (but i should and plan to "one of these days"). I have replaced caps and burned spade-lugs on the motor-run caps a few times, and I have replaced the fan-motors on each condenser unit, one time each, in 30 years.

[@munozinni]

Hola 👋 señor Dave!!! I just checked for one of those magohmmeters and I found one just like yours I think it’s a supco 5000 brand and looks just like the one you were using in your video I definitely going to buy it…Gracias for sharing your experience and great content…Saludos!!!👋😃👋

[@Wade-LS1]

Using a meg meter to test windings with cold oil in the compressor can give you an inaccurate reading. Always take off all wiring from the terminals when doing any check and also test the compressor ohm value. The internal windings are treated with a lacquer coating and that acts as the insulator because the windings are in oil.

[@chrisr6206]

Oh yeah, the unit is working fine and is about 21 years old, but due to this VID, I purchased the M500.....Tucson, Az. area (Sonoita actually).

[@Rusty1220]

Thanks!

[@Lettuce-and-Tomatoes]

I have a home warranty through State Farm that covers my home HVAC system. The deductible is 500 bucks. It would be extremely interesting to me (and other home warranty holders) to see a video on how to troubleshoot and repair 500 to 700 buck problems. I’m not too concerned about work going over that amount because that’s when the warranty I’ve been paying for kicks in and I’ll let a pro sort it out at that point.

[@EnigmaticJack]

You do understand that what constitutes a $500 problem in one geographic area doesn’t necessarily amount to the same in another, right?

[@wmcomprev]

While this tool can indicate a bad compressor, a good reading on it doesn't guarantee a good compressor. The motor may be hard to turn, causing excessive amperage draw even through the windings are good. Also, depending on the type of compressor, it may have bad valves in it; although, I suspect most are more of a rotary type that don't need valves. However, I'll agree that probably 99% of the time, if the windings are good, the compressor is good.

[@t.d.harris1311]

New stuff is made to fail, my grandmother had a GE refrigerator that was over 50 years old, it ran until the house got flooded and water got inside the compressor area and the people who help clean up threw it out.

[@jugears1081]

In 1972 I saw a program on PBS titled "Planned Obsolescence". They are building them worse every year, intentionally. I am a mechanical engineer. I graduated in 1972.

[@Garth2011]

We have a G.E. refrigerator made in the 1940's. Has a small freezer inside and we have to defrost it every year or two. Works like a dream, no fans etc. Quiet as a mouse and it uses 2 amps of power ! Its a keeper. The EPA and other departments would tell us otherwise including the power companies !

[@jugears1081]

@@Garth2011 I had one like that too. It got destroyed in a flood about 10 years ago. I wish I still had it.

[@DT-jz3wn]

My original thoughts were that the compressor pump would be the component to go... Not the dielectric strength of windings. How does pump wear factor in... Or how do we test it? Just gauge pressure?

[@diyhvacguy]

Yes your pressure split will tell you that. If your high side and low side aren’t off by much, that’s a good indicator that the compressor pump is done. That and noise levels

[@DT-jz3wn]

@@diyhvacguy thanks so much. I love your videos and really, really appreciate all the knowledge, time and effort that you provide!

[@TooCloseSeries]

We all want you to install our new system. 🥰 I've used filterbuy your advertisement on this video. Got the exact filter I needed. Perfect. ( I was not paid to make this statement)

[@CC-hv5hk]

Wonder how many good reviews this guy actually have . We will never know how his customers really feel.

[@robertgregory2618]

He's probably making good with 250K subs.

[@dalesumney8806]

Thank you for your videos. I just replaced my condenser , A coil, line set and VTX. WE ARE COOL NOW.

[@barryinkpen6026]

If you're going to meger the compressor you should remove all wires and then do your test on each terminal. Your test method could pickup carbon dust on contractors etc.

[@EnigmaticJack]

You want the terminal posts to be warmer than ambient temp when checking. Also pull all the wires off before testing. And lastly, scroll compressors react differently than regular reciprocating compressors…they’ll read low or bad when they are fine due to limited clear to can from windings. You gotta know these things if you’re gonna “teach” people

[@TrendyStone]

I had to replace 3 fan motors over 20 years. Eventually when the unit died we realized the wrong jumper was used on the circuit board when it was originally installed and my fan had been running too fast according to the service rating for it's entire life! That explains why I kept going through fan motors. Luckily they were only about $30 each.

[@bobboscarato1313]

I sold Fedders A/Cs. Long ago in the NY metro area!

[@MrHVACguy71]

love those old systems, they were built like a tank. I have a property with over 100 Gaffers and Sattler units that are 1971 models, I've never replaced an unit there. New systems are lucky to last ten years these days

[@Gerald-do9yg]

Gaffers and Sattler! Long time since I'd heard them mentioned! Glad to hear of their reliability.

[@MrPoppyDuck]

Tha start capacitor went out on mine. To be fair, that central AC unit was built in 1967 so I cannot complain. Ended up replacing the entire system a few years ago as everything else was original and would no longer keep up on really hot days.

[@wholeNwon]

Interesting. Why was it no longer "keeping up"?

[@MrPoppyDuck]

@@wholeNwon Unsure. Coils were reasonably clean for being 50 years old. System was charged. Evap coil drain tray was rusted away with some of the air handler so it leaked and damaged the garage ceiling. Was bittersweet to see it go as that system was built like a tank.

[@MrRjnr]

what brand did u go with now?

[@MrPoppyDuck]

@@MrRjnr Carrier.

[@jonathanschwartz8]

I know little about AC compressors, but the resistance of motor windings is only one test of a compressor health. Is this just step 1?

[@MrTIGERH1752]

First off, when using a megger, you need to be grounded to the compressor shell, and not a bolt on the machine frame. Compressors are usually mounted in rubber bushings to to reduce vibration transmission for noise control. Second, since the megometer, is measuring insulation quality to ground, it will also detect moisture in a system, and contamination in the refrigerant. We always use this device on annual inspections of commercial systems, to locate a potential breakdown, long before a failure can occur. Avery useful tool when used properly. Tim

[@woodwardbrandon]

My system is an 85, started looking at replacement options. It still runs reliably. I clean it twice a year. I wish things were still made as good as they used to be it a shame.

[@rogercook2292]

ohmmeter that uses higher voltage to check motor windings is a very good tool, but limited in scope of what it can tell you. many other issues with electromechanical devices that won't show up on resistance tests but kudos for giving average joe homeowners some direction in troubleshooting. I think a lot of consumers don't know the huge scientific and physics principles at work to remove the heat from the air inside of a structure and expel it outdoors (or vice versa in the case of heat pumps) and anything that can be done to demystify the process is always good.

[@fernandodiaz5749]

I wish I could buy an ac system back when things were built to last, I paid to have installed 2 systems since a bought my house, and same scenario on the current ac unit on my house is relatively new and started acting weird already, now I know why, things are not built to last anymore.

[@wholeNwon]

OR you have had bad installations. Meticulously correct installations (the ONLY way to do it) are rare. The brand of AC system is relatively unimportant but the installation is extremely important.

[@fernandodiaz5749]

@@wholeNwon sadly reality that tells you how bad things are currently, quality degrading on both ends, products and skill labor.

[@Garth2011]

I guess it boils down to, systems today will not tolerate a poor installation like the old stuff would and of course, the old stuff was more reliable in their components.

[@wholeNwon]

How is it acting weird?

[@wholeNwon]

@@Garth2011 I think that the old copper evaporator coils were superior and usually very solidly built. The new scroll compressors are said to be more reliable than the old piston units though I never had trouble with mine over 47 yrs. and they were very quiet. Circuit boards are usually much better than trouble shooting with a wiring schematic that may be falling apart. New systems cheap out with Schrader valves and piston metering systems rather than TXVs (that can easily be added). Capacitors don't last as long but they are very cheap and everyone should keep a spare.

[@valeriegould1769]

Thank you for this. I called someone to check our AC after I watched this a few months previously. He tried to show me that it wasn't checking out with the megometer showing a red light up high. The trouble was the "On" light wasn't lit. I asked him why it wasn't lit and he said he didn't know. He also told me that my heat exchanger had a crack and was leaking carbon monoxide, and he should red tag it. I pointed out that there were 2 Carbon Monixide detectors right buy it. One a straight CM detector showed 0. The other was a combo smoke CM detector - Neither had gone off. He said they were probably defective. Nope. Well, now I know who not to call. Shaking my head.

[@ramonestrada38]

As an industrial electrician of many year's make sure you disconnect and isolate the motor from all possible wire insulation and capacitor leaks to ground. Also the ground connection should be very clean to avoid a high resistance and give you a false reading. Nice video 👍

[@Buc_Stops_Here]

Actually, had different problem. it was a combination of the compressor and capacitor. It was showing 2 volts below spec. He suggested I buy an Install Hard Start Kit. This helps the compressor start up and come up to operating speed quicker. The start assist reduces winding stress and the production of winding heat, saving the compressor from additional strain and increases the life of the compressor. The heat pump is now 12 years old, so if I get another 2 years out of it of year-round usage in CT that is a pretty good life.

[@steveb6371]

That’s why I am not changing out my 1987 Trane unit.

[@Barry-p4m]

Better off keeping it my friend

[@Mrpaulgs]

Isn't there more than one failure mode for a compressor? Could it not have a good AC motor but a seal problem or other mechanical issue with the compressor?

[@AMMCElectronics]

Well, that only represents the status of the motor coil insulation. It doesn't mean that your valves or pistons or rotary things are damaged or worn out... also, if the chassis of the compressor hasn't a good connection with the AC case, the result can be OK too. Moisture, capacitive coupling, etc, can also affect this reading, that's why you can see some oscillations in the reading. It's important that this devices need high voltages to read souch high impedances. It doesn't affect the motor, but for inverter motors it's better disconnecting all wiring from the motor to not affect the electronics.

[@johnlegarre3667]

Fedder was a huge manufacturer of window/wall units in the 50s-60s.

[@silasketgaskets8709]

some good videos on how they rebuild a/c compressors and can see theres more that can fail besides the windings. most common is burnt capaciter and easy to replace. on an old mini split the remote receiver board and indoor pcb failed. i replaced them with a single universal pcb with onboard receiver. works great ali express about 25usd. worth using an under / over current protector as the expensive pcb's can die. also be very careful with caps as they can store electricity even if power turned off. i use insulated gloves and tools

[@ThangNguyen-gi6sk]

I wish u live near me! U are such honest hvac tech

[@Watchyn_Yarwood]

Neighbor called me to come to her house. HVAC contractor was trying to charge her $320.00 to replace a wire on the condenser. I disputed the charge and fortunately the contractor tore up the work order. Two days later, she called me and said it had stopped blowing cold air. I walked over, looked at the condenser and the wire he replaced was burned up. Again! I told her wires don't just burn up. Something caused it. I looked at the contactor and saw it was completely burned. I went to a HVAC supply house not far away and bought a new contactor for $16 and new capacitor for $15, replaced them and the burned wire and it's still working three years later.

[@Garth2011]

Lots of those "supply" L1 and L2 wires heat up due to a poor contactor interface with the load. Because of their cost, I would always replace the contactor when repairing burned supply or load wiring because, as you say, wires don't usually fail, its the current that burns them up so its a connection that is bad which could be a wire terminal, the contactor, a loose screw or terminal to the supply L1 and L2 on the contactor etc. Lots of techs also will replace the capacitor when they replace a fan motor which makes much financial sense as the good ones are only $30 and many motors will come with a cheap Chinesium cap.

[@TSGEnt]

Thank you for this demo. Very valuable tool. Learn something from you every time. Also, the bottom line, they don't make them like they used too. That and the higher pressures sure do shorten the life of these things.

[@adrian-xy7zt]

Just stumbled on your channel and I love it. Keep those videos coming.

[@QuantumRift]

we have two bryant heat pumps, and I keep a couple starting caps handy in my tool kit.

[@charlescoffey9523]

While I agree that often it is something like a capacitor for the reason a unit does not start. Electrical shorts, which can be tested with a standard multimeter, granted there will be a few cases where the short is not seeable at 9 vdc but those are very rare. But there are other factors beside this, a bad valve in the compressor would show a good compressor in this type of test. A better way of checking for electrical issues is both resistance of windings and current draw compared with exchange temps.

[@aldrive622]

Hi, I wonder what is the unit for the numbers on the megohmeter? I supposed the numbers on the meter are in Ohms, correct? not mega-ohms? If so, I can buy a cheap $20 multimeter and do the same. if not, what's special about this meter that regular multimeter can't do? Thanks.

[@rickmoll16]

The Supco M500 testing range is 20 to 1000 Mega-ohms (20,000,000 to 1,000,000,000 ohms). It is also testing at 500 VDC. A typical multimeter tests resistance at only a few volts. An Insulation Resistance Tester like the M500 uses high voltage to stress test the insulation on motor windings.

[@rogerdirks947]

If I were doing the testing, I would have all 3 wires disconnected at the compressor during the whole process. With only one wire disconnected at a time, you would be reading through the very low resistance of the windings and back into the capacitor and contactor,which can give a false low reading on the megohmeter.

[@ronroth8788]

My blower fan on the air handler was not always coming on. The AC man says I needed a new system. I replaced my thermostat (15 years old) and all is well.

[@chrisr6206]

OK, bought the M500, just went to my A/C to check it and the only item I can find to plug into on the compressor is on the side of it (I recall you saying in this video the access might be on the side): I have to unsnap a plastic covering which shows 3 SOLID probes....I connected the M500 and it didn't register on the tester.....I tried all 3 with the black to a ground (frame screw). It now occurs to me that perhaps the GROUND was not good? Perhaps I'll fiddle with a BETTER Ground. What say ye? thanks, Chris

[@kevinc8811]

Yes it sounds like you have a bad ground connection.

[@jamminwrenches860]

Metal nameplate, made to last. Printed sticker nameplate, 10 year product.

[@icanreadthebible7561]

Good rule of thumb! Made in Mexico -- 5 years Made in China -- good luck getting it replaced under warranty.

[@billsimpson604]

Great point.

[@mediumrare9051]

Genius

[@Garth2011]

Just like hood ornaments on cars...!!

[@FatherTimeIII]

People like this keep me in bizz, keep it up brother.

[@pwilly_1]

Fedders was one of the most robust AC brands made back in the day with well designed refrigerant circuits, etc. Why are they no longer around? Likely because their equipment wasn’t designed to fail (planned obsolescence) like most equipment today. That said, sizing it right, installing it right with a straight forward way to maintain it (think correctly installed high efficiency media filters) are the 3 critical factors in system longevity, maximum cooling per watt at the lowest achievable operating cost - no exceptions..!

[@JT-lq4yd]

This tester looks for electrical "leaks" in the electrical conductors insulation inside the compressor. Nice! The compressor on my unit sounded like a rocks in metal can being shaken😅.

[@Ratlins9]

@JT-Iq4yd Thank you for explaining what this tester does.

[@james10739]

I mean i guess that is just testing the motor windings it doesn't really tell you anything about the compressor if the rest is worn out but i guess if it says bad its bad but good doesn't mean that much

[@Luis-ob4xq]

Thank you so much for your videos ! You make the learning of all kinds of repairs and maintenance that regular people can make. Just a question: Do I need to use the same brand on the outside and inside units ? Thanks again !

[@Harry1s]

You should always pull all of the wires off before ohming out a motor. If you don't it might back feed through the wires or short out against the compressor or motor and give you a bad reading. It's also a good practice to ground out to the piping or casing of the motor. This gives you the best grounding. Remember this test is testing the insulation of the windings to ground. It does not tell you the condition of the pumping capabilities of the motor either.

[@markcondrey2297]

I just use a digital multi tester myself. Nothing fancy just set it read ohms. I can actually use this puppy for other things too👍

[@alnonymous9361]

Your multimeter only measures resistance with a small test voltage of half a volt. To test motor insulation resistance you must test at 500 volts for it to mean anything. Because motor insulation breakdown is not a linear resistance & a typical multimeter wont detect a fault even if it tripps breakers & blows fuses. My personal experience.

[@scoobtoober2975]

Dave, i'm getting ready to buy parts. How long would you let a line set run for. No burn out. 25 years or older. or could that copper still be good? What's the best practice. Less than 20 is good. Or 30+ years. Money is not the object. Quality and longevity. I feel like some techs would no question throw the old one out.

[@diytwoincollege7079]

85 was just about the last of the years where quality stuff was made. Fedders was a good brand.

[@DavidAnderson-se1or]

Could the Supco also be used with a smaller mini split system to check the compressor? Your channel is one of the best on YT. Very informative!

[@UtahDarkHorse]

Is it possible on the first system checked that you simply didn't have a good ground for the tool? I run across this alot on cars. Not sure that clipping onto that bolt "guaranteed a good ground". Just askin. I really live your videos. thanks for sharing the info.

[@joeguilfoyle1922]

I work in an office building where the HVAC runs off of 2 Big Chillers and 2 AHU's on each floors. I was wondering if this Megometer will work on those compressors as well? Will this work on all compressors? Refrigerators, freezers, etc? Thanks for the video.

[@jmead6121]

back in the 70 , 80 90 we never ever pulled an Vacuum on R 22 .....bk then it was purge & go

[@IanPatterson-y4v]

Great video mate, had couple of locked old compresser , mechanical seizing after 20 years, great little tester , I going to invest in one

[@bernardaflores1720]

Great video, does the Megometer also check the compressors for refrigerates and freezers etc??

[@donb3026]

Applaud all your content and HONESTY 🎉🎉🎉

[@RalphKramden-il5pf]

How about explaining what you're testing, resistance across the compressor coils?

[@1223army]

I like to know more on your views on nitrogen check system , how long does it takes and can you tell me the value of the doing the test in regards to the coils.

[@Pepaw-Bill]

My favorite first question when I call a HVAC company to fix one of my two heat pumps is “how old is the system”? When they do this I ask them for their 608-610 certificates and their Freon purchase license. They ask me why and I say if older system repairs are beyond your abilities I’ll need to call a more experienced HVAC company.

[@rvblueagle]

question - is that gizmo checking for the motor winding? what about the compressor? how do you know it will still produce the pressure the system needs??

[@james10739]

I assume the reasons the insulation breaks down is possible thinner or of a lesser quality but aside from that is heat definitely anytime it goes into over temp

[@RobertWork-wm8qx]

You could also just use a stand Volt-Ohm Meter that you probably already have... No need to buy a separate tool. Also, you should isolate components before testing them in this way.

[@glennphelps9300]

Yes and no. Standard ohm meter just uses a couple of volts and may not show any insulation breakdown at that voltage level. At 500 volts, you are more likely to see insulation breakdown if it exists. Yes though on removing all 3 compressor leads prior to test.