Possibly a hard start kit needed...you don't mention the age of your AC system...and/or a different dealer/tech...

IMO

Call the local Carrier distributor. If the local HVAC service people don't know whats wrong with it, replacing the compressor, etc, is no solution.

Hard start kit was the first thing installed. (I was variously told it was a 'hard start kit' and a 'hard start capacitor'.) The Carrier outside unit is 10 years old; been doing this for 8 of the 10. The inside Trane air handler and coil is 30 years old as is the piping between inside and outside.

Hard start kit is exactly that... it starts the compressor that is having a hard time starting. Problem is hard start kits aren't created equal.

On top of that a hard start kit will not work in all situations. Most modern units made in the last 10 years typically have a scroll compressor. They typically do not need a hard start kit. With that said, if you put the proper hard start kit on a scroll compressor it aids in the starting of the compressor and this reduces wear.

The hard starts come in different varieties the two wire kind, which is the cheapest and most likely to not do anything or much of anything to help start a poor ailing compressor. They look like a big stick of TNT with two wires coming out the top of it. (reason I say TNT, is they often fail by exploding or burning up in some form)

There is a 'kit' that is a 3 wire that is pre-packaged. For the most part these work ok... but they don't provide necessarily the right relay or the right start cap for every compressor. So there's probably a 30-50% chance if you have one of these that it's not doing much of anything either. Less likely for these to burn or explode as long as it is hook up properly.

Then there is the self made 'Kit'... meaning the person performing the service is knowledgeable enough to know which relay to use and which capacitor to use together that will have the highest degree of success in starting the cranky compressor.

However, a cranky compressor that can't start on it's own... especially if it is a scroll compressor the writing may be on the wall. The most common reason for compressors with trouble starting is bearing seizure within the compressor shell. Once the bearings seize the game will be decided for you.

So what causes bearing failure with in the compressor shell?

Improper or lack of return oil getting back to the crankcase of the compressor. How did the previous unit fail? Was it due to a bad compressor and why was it bad?

Just to be clear - when I say 'replaced 10 years ago', I mean the entire outside Trane unit was replaced with a Carrier (i.e. not just the compressor but the entire package). The company is local to my suburb, good reputation, etc. and had previously serviced the Trane air handler. The Trane's compressor wouldn't start or attempt to start. That is, no humming, nothing, just dead. (The fan ran OK.) When I was told the entire unit needed replacement, that seemed reasonable since it was 20 (maybe 22) years old. It never needed any repair all that time (unlike the inside Trane airhandler).

Of course, living in the Chicago area, I've got 100's of HVAC companies to choose from, but which one? And, of course, there's a nice service fee for just coming out even if they don't fix it. Not that I begrudge the service fee, I'm not expecting something for nothing, but how do I know that THAT company's tech knows what he's doing? I guess I'm going to have to bite the bullet, research companies via online reviews and give another company a chance, especially since there are hard start kit options and not all are created equal (which I didn't know before - thank you Austin Air Companie).

When this first started happening and it wasn't fixed, everything I read online said "you'll be lucky if the compressor survives the summer". That was 8 years ago and I could still live with it. The reason it's an issue now is, if all goes to plan, I'm going to sell the house next year. Being a relatively honest feller, I would disclose the AC issue. However, if I were the buyer, "it works fine once it gets started after a few tries and has been doing this for 8 years" would not be reassuring.

Reputation doesn't necessarily mean knowledgeable at repairing older systems, because there are companies that exist for just replacing equipment.

I know that statement won't give you any fuzzy thoughts and you probably realize this to one degree or another.

Yeah I realize you replaced the outside condenser last time it failed. But whatever caused the original compressor to go south was probably left as is. Which 'may' be why you have had this problem for so long.

I say may be, because it's also possible something was wrong with this compressor from the factory. Given that the original Trane compressor failed a similar fate leads me to believe some work was done to the air handler that might be having an influence causing these issues.

It's unlikely you will pick a better company by merely using reviews... this helps to a degree but it still does not classify a company as having high technical abilities. Given the nature of this and the cost involved and the statement that you plan to sell this home lessens your chances even further.

No company is going to put in the time to try to rectify a high level problem if you're not serious about it.

Better off with a whole new refrigeration system IMO. The evap coil is old, the lines are old, both will start leaking at some point. If your going to be honest in selling, you would just sell as is and take the hit on price for a new AC system. That or fix it before hand. Patching it and making it look like everything is fine is not honest.

I mean, you can say the AC was replaced 10 years ago, its both true and a lie because only half the system was replaced. The other half is a dinosaur.

@Vith - seller disclosures (as I've dealt with before) only disclose if a system is working OK, without problems, with the answer for each system a checkbox- yes, no, unknown. Age of the particular system is not part of the disclosure. For the AC, I'd have to say 'no' and explain why. That's why I'd like to have it repaired, if possible, so it IS working OK.

If a potential buyer asked the age of the system, I would give the correct age for each component, but the onus is on the buyer to ask the question in the first place. Just as I wouldn't volunteer that the electrical system (wiring) is as old as the house (60 years) or that the roof is 13 years old, but would certainly answer 'yes' that they are working OK, because they are. Granted, a 13 year old roof is more likely to fail than a 1 year old roof, but the buyer has to ask the question and then weigh that in their offer. But starting from working OK is always better than 'no' or 'unknown'. If I can get the AC professionally repaired so it is working OK, there is no deceit in answering that it is working OK.

However, I am leaning towards replacing the entire system and will start getting quotes in the autumn. I have no way of vetting any company or any specific tech a company might send for the debugging skills mentioned by Austin Air Companie. All it would be is yet another 'let's give it one more shot with yet another company'. A totally new system, would be a selling point and that would definitely be included in the listing.

from a purely financial standpoint, you are better off keeping the existing AC and letting the buyer (after you correctly disclose the issue) deal with it. You won't get near 100% back on what you get paid, and they may rather have a concession and just keep on as you have rather than use that concession to replace it right away. The caveat would be if you are in a starter type of home - those folks likely would rather have a new system that's wrapped up in the mortgage as they are typically thin on cash after the downpayment.

It is a starter home in the sense that it's a 1950's tract house in a tract subdivision all with similar homes. But it is in a suburb very close to Chicago, which seems to be the 'in' place these days instead of going farther out where the lots and homes are larger (although, IMO, not constructed as well, but that doesn't seem to count for much these days). On the other hand, what these homes are going for is just insane. Not west coast insane, but insane for this area, IMO.

The other thing is, I'm sort of a perfectionist when it comes to home maintenance and this is the only flaw in the house (well, in my eyes, at least). Also, if things don't work out, I won't be selling. I'll know better later this year and wouldn't replace it until the winter in any event. It's an attic system and don't want the tech guys working in death valley. Also, will have to pass this by some real estate agents, when I start that interview process. And then there's the replacement cost. No idea what it would be. Replacing the outside unit cost me just under $2K 10 years ago, so I know it won't be cheap.

The real estate agents will probably talk you out of replacing the AC. The real estate agents will probably tell you to include a home warranty with the sale of the house. Then let the new home owner and home warranty company duke it out over mismatched system argument.

At least that's what they do in Texas. wink ~ wink.

In the end this will get you off the hook. Being that you're in Chicago I don't know that AC will be at the top of the list of a prospective home owner. They will probably be more inclined to a lower price especially if interest rates start ticking up.

If the home warranty company is some how able to look past the mismatch argument, the home warranty company will probably pay for replacing the compressor... then in all reality a few years later the compressor will fail again and the process will start all over again.

Now, hopefully when you move from this place you don't find yourself in such a predicament. But if you don't replace this system at this house, you'll have the money to do it at the next one.

I say this just to show you common practice in residential real estate monopoly game.

Central AC isn't 100% necessary in the Chicago area (many people only have window units in bedrooms). However, in my localized area it definitely IS necessary because of the proximity of the airport. The noise has gotten significantly worse since the runways were reconfigured/new ones built. (One of several reasons I want to move, although it hasn't discouraged people from moving into the area and paying princely sums for the homes - the 'close to Chicago' attribute.)

The next house will definitely not have this problem because it won't have AC. I dislike AC with a passion and prefer wide open windows and fans, but that is no longer possible in this area. The next home will be in Michigan's Upper Peninsula (ergo my moniker) where AC is totally unnecessary.

I 110% agree with mike_home. Evidence point's to voltage drop being the root problem. That's likely what was wrong when unit was replaced before and will still be there if unit is changed a second time. About 1 out of ten hvac techs know what voltage drops is,and only half of those know how to remedy it. An electrician might be the better choice for testing and fixing it. Even if you get lucky and find a tech that know's how to test for voltage drop,he would probably refer you to an electrician for the repair.

It seems klem1 and I are interested in trouble shooting the problem and not giving real estate advice. I hope the OP can find a tech who knows how to use a voltmeter.

That is an interesting idea guys. Perhaps a short or loose connection somewhere between house panel and compressor?

I would check the wire gauge of the service whip and the wiring back to the main circuit breaker panel. I also would check the voltage coming into the house.

In view of how old the house is and how many people might have messed with electrical since house was built,any thing is possible. Not something that can be pointed out long distance but shouldn't be no hill for a climber on site.

Extremely unlikely because as the guy said... eventually the unit starts and runs fine.

Voltage drop = no run. "If voltage drop occurred while unit was running... it would not stay running." No where does OP say anything about unit cutting out while after starting and running. You have to know what you are talking about to come to such conclusions. LOL. Does a car keep running if there is no gas? Can a car be hard to start, but then run fine once started? Yeah ok, common sense. While a car is a poor comparison more people understand the operation of a car than anything else I could use as an example.

voltage drops tend to stay, not magically disappear and reappear.

But thanks for playing....

In over 22 years of diagnosing only 1 voltage drop problem... if you have a voltage drop you will know it quite easily. (More complex problems in regards to start up? Uh no. Guess again and again and again.)

More common to drop a leg from the pole... while also rare that's happened about half dozen times in 22 years of running service. Central AC Unit won't start with only 120v available, that confuses people because some things inside the house will still operate normally as long as it doesn't require the full 240v to operate.

In Vegas, they give you odds... in a forum board that's also what I give.

Magic 8 ball --- out.

Why do the lights dim momentarily when a large motor turns on? When you find the answer to that question then you will begin to understand why this theory is plausible.

"Why do the lights dim momentarily when a large motor turns on?"

Is it because the homeowner's car is almost out of gas?

"Central AC Unit won't start with only 120v available, that confuses
people because some things inside the house will still operate normally
as long as it doesn't require the full 240v to operate."

Nonsense. Nominally one half of the 120 Volt loads will not work if lose one phase. So the homeowner will see some room lights working, some not, some receptacles working, some not, one porch light working, maybe not the other, possibly the doorbell stops working, maybe power to the pipe heater for the vented pipe ceases to heat, it goes on and on.

Given this happens to a homeowner do you honestly believe the homeowners would decide to call the heating and A/C guy?

"Martha. Look the range is working, the clothes dryer died, no HP/A/C, the lights in the hallway and two bedrooms are not working, the doorbell stopped ringing, and the TV will not work. I'm going to call the A/C guy." I think not!

And the continued ad hominem attacks when coming from a position of a lack of knowledge do not reflect well either.

I didn't say it sounded logical... but it did happen the exact way I described it.

Some people don't cook, some people don't do as much laundry as others.

If the AC stops working in hot climate how soon would you notice it?

So you think I am going to come here and forget about every AC call I've ever run? LOL.

hominem attacks? How is telling someone that something will not run without full power an attack? You're reading into something that isn't there.

so we are going to compare this to lights dimming? The OP is talking about a cranky compressor not starting, maybe you should start a new thread... LOL.

Replace the starting capacitor.

If there is corrosion or a bad connection somewhere and it is on the threshold of either working or not working, then yes it could happen.

Don't assume the problem is inside the home. The OP's house could be the last one on a long run from the transformer. The voltage entering the house's service panel might be marginal. During peak electric usage utility companies may introduce a brown out if there equipment can't keep up. All of these small voltage drops creates a significant drop at the condenser.