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.

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.

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.

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

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

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!

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.

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.

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.

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.

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.

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

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.

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.

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.

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!

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

Proof that the stuff they make today is $hit. 30 years old and still good while a 5 year old system is on the way out. We need a car guy like this HVAC guy.

Love that silver KZfaq 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

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!

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

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)

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

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"

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.

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

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 👍

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.

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.

Thanks for all your help 🙏

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)

You need a free way to enter your tool giveaway, or it's considered an illegal raffle. Providing a way to enter by mail is considered free, as you don't get any part of the cost of the stamp. I have no skin in this game, just trying to keep you from getting in trouble. Raffles are illegal under Federal and most State laws, with exceptions for certain charitable organizations, as it's considered to be gambling. Also, you may need to restrict this to US residents, as laws vary by country. Canada requires a skill test under conditions I'm not totally familiar with.

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!

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

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

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.

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.

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

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).

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

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

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.

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

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.

"Even though this is a relatively new system"... It's a Goodman.

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!

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

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.

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.

Love these videos, they fatten my wallet every time one comes out!

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.

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.

Thanks so much for this info. I will get one of these and test.

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

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.

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

This videos has some major issues, But lets get one simple thing straight a bad compressor does not automatically mean you need a completely new system.

Thank you for the advice 🎉

My next door neighbor has a 1979 Fedders that still works fine.

Just ordered it on Amazon

Compressors that test bad according to this megger are not necessarily bad. According to Emerson, you can have a good compressor megger out to as low at 0.5 megaohms, where this meter will tell you 20 megaohms is bad. Additionally, contamination can cause low readings and if you remove the contamination, you remove the low reading and the compressor is fine. I suggest reading Emerson Bulletin AE4-1294 for more details.

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.

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 !

Hi, nice video. Thanks!!! Saludos desde Tampa Florida

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!

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😅.

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.

*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.

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

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..!

The capacitor thing almost got me, i hired another company (family friend); he is wasnt even sure. He threw a jump start cap on, and jt held for a month. I bought a new cap, swapped it out. Boom, 5 years and still going. 🤜🤛

As always, great videos and excellent information. Unfortunately, there r so many con techs everywhere!!

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!

Great informational video!

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.

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.

Nice video. This restates one thing I am already well aware of: that this repair industry is chock full of crooks who make a great living by routinely overcharging and misleading homeowners. I have seen enough real life examples with my own eyes.

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.

U R awesome. I was an electrical engineer, and we did power factor insulation test of hundreds windings using Megger and Doble. It is a best test

Great advice thank you

Super cool! Does this work for variable inverter compressors as well?

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

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

Fedders! the very first house that I lived in as a child had that brand. We are talking 1960!

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

Thanks

Very helpful.😁

I saw units like these in the 90s in Germany. This is the first time I've seen the design here in the US.

I used to use this when I first started in the industry, found it to be 50/50 when saying a compressor was bad. I would just tell the customer that one of the test showed the compressor was going bad so not to be surprised if it died suddenly. never sold a customer a new system or compressor based on that reading alone.

Awesome, thanks!

It would appear to me that this is simply an ohm meter. All it appears to be doing is checking the resistance of the insulation to ground on the wires in the motor. A motor can fail in more ways than an insulation breakdown in the motor.

In our neighborhood bunch of us started to get written estimates and the diagnostic reports etc and posting those to our community facebook page. Naming and shaming these crooks was the best thing that could have happened to the residents and honest services companies. I had a company threaten a legal action about sharing the estimate and I happily asked them to go ahead, as I will request a civil jury trial and request discovery. That guy shut up so fast.

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.

Fedders was the best Got a 5000 with old refrigerant and it cool a complete ranch house. No kidding Like an icebox and I still use it Thats why it still tested good Maybe oil filled cap I would like to dee the the difference of the electric draw though.

Thank you

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

Try ur test by putting the ground clip on low side copper near compressor!

No school like old school. The antique rocks 😂

I worked for the state and most anything can be repaired. You can replace a condenser but most service co's will sell you a whole condenser since that is the only way they will guarantee it.

Good info.