OT- AC woes

[Dunc]

I have an 8 yr (of cooling; system was installed the previous autumn, post cooling season) old ac system. Worked fine last summer. First heatwave this year & it works 'fine' but there is no cool air. The fan blows, the compressor kicks in (I think),the thermostat works (checked it out using a net video for guidance). Checked the coil inside the furnace & no frost/icing. Outside coil is not plugged with debris. Methinks, based upon previous episodes (2x) that it is a lack (perhaps total?) of refrigerant.
I am wondering why this is repetitive. My car's ac system is older & it has *never* lost any refrigerant. Repair techs blame leaks around valves but the same type of valves are in my car's ac. Internet videos I have viewed seem to be of two camps: one accepts the leaky valve story & the other says it is a sealed system - therefore, you have a leak.
If it is a non-valve leak, how can this be determined? More on-point is it worth it given the cost of repair? Some components remain under factory warranty. I gather that refrigerant costs alone would be in the $500 -$1000 (Cdn) range. By the time diagnostic services plus leak repair(s) - assuming the leak(s) can be found and are repaired/replaced - I seriously wonder if it is worth it vis-a-vis a new machine with new refrigerant already included in the package.
Not sure of site rules about "names" so I have omitted.

Observations, suggestions, whatever, desperately requested. Thanks!

[Mike279]

If everything seems to be running, a lack of coolant is a prime suspect. Feeling the small tube near the furnace coil it should be warm to hot and feel like the coolant is running like water in there. I have a sniffer that can find leaks that was given to me by a friend. It found my small leak(so small it took ten years to leak enough to fix) and I had to machine a new part that is still in service today ten years later. After studying the new systems in anticipation of my 30 year old system giving out someday, I would seriously consider a split system. I see many that are heat pumps that are as efficient as gas furnaces in temps as low as minus 15 degrees F. Either way they are making some real strides

[PStechPaul]

If this has happened several times with the same system, I would suspect a design or quality problem. You might try googling your particular brand and model to see if similar problems have been experienced by others. My only A/C is a small "portable" window unit I bought used around 1978 for $35, and the only service it has required was a motor capacitor. You might also consider installing window units in rooms that can be closed off, and running them only as needed.

[OaklandGB]

I know zero about AC units but the guy who services mine told me if it runs low on refrigerant, and starts to run warm air only, don't try to run it. Apparently there is also oil that circulates with the refrigerant and if low can spoil the compressor. Maybe he was feeding me a line of BS, but that's what he said.

[Tom S]

Yeah, sounds like a leak.

Is your indoor unit an aluminum coil? Aluminum coils are better now, but they've had their teething problems and older units can be prone to leaks. Non-repairable, might as well replace at that point. Coils (either aluminum or copper) on these types of units are the most likely place for leaks. They are one of the most costly parts of the equipment, and the accountants are constantly trying to squeeze a few dollars out by using thinner materials and cheaper brazing methods. There could be a leak elsewhere, but that's where I would start.

Problem is, to get someone qualified in to find and repair that leak could easily cost you half of what a new system costs. Unless you have a tank of nitrogen in which case you could get busy with some soap water and try to track it down yourself. You could get them to just remove the indoor coil and cap the lines, then pressurize the outdoor unit and see if it holds pressure over a few days to see if just replacing the indoor coil would be an option, but I'd bet they'll be pushing to install a new system.

[darryl]

I'm assuming the huge cost is to get somebody in to test, possibly repair, then re-fill the system. Last time I checked you could get a small refill can for $15 (your system would obviously need more than that) so the refrigerant cost alone wouldn't be all that much.

I wonder if your system is made with that pinhole copper tubing that was around then. Given the scare about metal prices, replacing $50 worth of copper tubing would probably cost you $1000

[Paul Alciatore]

I have a central AC unit with a leak. I am waiting until my wife feels comfortable with people working in the house and then I plan to have the inside unit replaced. That is the recommendation of the AC guy who I have been using for over 20 years and I trust his judgment. He was nice enough to refill it once for free and when I needed a second refill, he charged me $90. But, as I said, we have a history.

OK, your problem: You seem to be a bit shaky on the compressor. It should be fairly easy to tell if it is running. The fan in the compressor unit will make one sound and the compressor will make another. Even if you are just standing near it when it starts up, you should be able to hear the difference. Beyond that, you could remove a cover or grating and just put your hand on it to see if it is running. If it is not running, then an electrical problem is likely the cause. Of course, you could also have a bad compressor. If it is running, then you probably have a leak. That gives you three ways to go from here.

Compressor not running: I would put a clamp on amp. meter on one of the compressor's wires and see if any current is flowing. Current flowing but compressor not running means a bad compressor. No current means an electrical problem; the biggest suspect would be the contactor. Contactors are easy to find and replace. Just be sure to use the disconnect to have NO possibility of any Voltage in the unit while doing it. There should be a disconnect withing a few feet of the compressor unit.

Compressor is running: You probably have a leak and there is no freon in the system. Leaks could be in either the compressor or in the evaporator (inside) coils. Finding a leak without equipment can be difficult.

I would strongly suggest that you find a good HVAC man/company and listen to them.

[Dunc]

Thanks for all the insights. I have determined the compressor runs (as no cooling, I turned the ac off). Thankfully, heat wave has broken and it will be seasonal for the next 7-10 days.I checked with the mfr & my system is warrantied (parts & labor) until Sep 2021 tho this does not include refrigerant. I have, per the mfr's instructions - called an HVAC company that is a factory authorized distributor/installer. Awaiting diagnostics...

[thaiguzzi]

Needs re-gassing.
ie refilling with refrigerant.
Get the tech to check for leaks with his gauges when he refills.
Just to make you feel even worse, and a little gloat this end, one phone call here and we have the service guys out next day.
Two men, ladders, tools, clean inside and out, vacuums, blowers, suckers, re-gas, all done and dusted inside an hour and gone.
Total cost - $30....

[JoeLee]

It sounds like it's just low on gas. Should be easy enough to check. If you keep loosing it you have a leak somewhere. Should be easy enough to find. Likely place to look is evaporator coil and condenser coil. Possibly any joints in the lines, but how many of those are there ?? one at the condenser and one at the evaporator, elbows etc. Unless the compressor itself is bad, running but not compressing. Who is it made by?? Don't say Harbor Freight.

JL.................

[Tom S]

If you keep loosing it you have a leak somewhere. Should be easy enough to find

Lol. Sure bud.

[CCWKen]

A leak would be a prime suspect but don't over look the compressor. Just because the condenser fan is running doesn't mean the compressor is. I had to replace the capacitor twice on mine. Also, have you cleaned the outside condenser coils in the past year. It should be done every year. While you're there, make sure the compressor is running.

[Dunc]

Compressor seems to be running but actually compressing... dunno, as there is likely nothing to compress. I have a maintenance contract for hvac, the machine was serviced last spring (2019); postponed, by me, for this season due to non-operation. That aside, the exterior coil unit is clean.

[Dunc]

End of the saga...
Had an hvac tech in to check.. inside coil (evaporator?) has a leak & is not repairable. Someone previously noted that this is the weak link in the chain.
Original installation was thru a big box hvac subcontractor. Both big box & sub are out of business (not covid-19 related). The manufacturer provided a parts & labor warranty good to Sep 2021. However, any hvac business that is a rep for this brand will honor the parts warranty but will not honor the labor part. Strange... fee too small?
Onmly goes to show that most warranties aren't worth the paper they are written on - yes, I have a piece of paper, fwiw.

[Mike279]

Probably wouldn't have fared any better paying a real business more and getting the same result. That's how my nephew ended up with his new house. Five years in and both A coils leaking. No good answers. He spent quite a bit and had them changed them out, hoping the new design will last more than the five years the first ones did. Sad, all brand name stuff and they did not stand behind any of it.