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AC not cooling, just had it charged middle of last summer

2K views 26 replies 11 participants last post by  stgeorgeaircare 
#1 ·
Hi Everyone,

I'm trying to troubleshoot an AC issue- it isn't cooling. I have a split unit AC and gas furnace setup. Here are the pertinent specs.

Goodman furnace; GMPN0804; 90% efficiency; single stage blower; 80k BTU
AC Condenser; Kenmore Sears & Robuck; 867.814840; 80oz R22 (freon)
AC Evaporator; Sears & Robuck; 867.81522; 10oz R22 (freon); 2.5 tons

I live in climate zone 6 (Minneapolis, Minnesota). House was built in 1977; 2050 sqft split entry with many windows facing east & west with no tree coverage.

I have sealed my ducts with high-quality foil tape. Most ducts I can see from the basement unfinished utility room where the furnace is located. Most of the return air channels are routed through wall cavities between joists.

I deep cleaned my condenser coil middle of last summer along with recharging my AC system (I have a leak somewhere). I replace my filter quarterly- usually use a MERV 8.

I've had perpetual problems with this AC since I purchased the house 12 years ago. I've needed 3 or 4 freon recharges- nobody has ever been able to locate the leak. I've had various HVAC technicians inspect the system including my utility's warranty repair service.

Is it possible that my freon leak has become so large that a full charge has already leaked out since the middle of last summer? The AC was only used for one or two months after it was fully charged. When I turned the AC on this year, it did cool really well for one night. After than, it hasn't worked at all and the ducts are not cold to the touch above my furnace in the box where the A coil is housed.

I'm so frustrated... :crying:
 
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#13 ·
Yes, Gemaire is a distributor and they have the best technical support group in the Southeast USA. They monitors warranty replacement reports for manufacturers and collate the data for their own purposes.

As far as Schrader valve leaks, that's a service issue, not a manufacturing/equipment issue. Even then, I haven't seen many issues with the newer valves (in the last 10 years) when they are installed correctly but I've seen copper evaporator coil leaks skyrocket due to the cheap, thin, lousy quality, recycled copper used today.

The "someone" you're referring too is an ACTUAL HVAC tech(s) or the service person whom is involved with the unit must understand best practices of FINDING the leak. Most techs and HVAC companies dont have the skillset (been taught), patience or diagnosis to find leaks they want to upsell to a unit, condemn and resell a part with extensive labor or pass on the issue.

Not sure what you're trying to say here(?) I agree most of the HVAC company service personnel are useless but you appear to be using their experience to support your assertions(?)

Bottom line, the OP has a leak and he/she needs someone competent to locate it and take the reapir from there.
 
#14 ·
Not sure what you're trying to say here(?) I agree most of the HVAC company service personnel are useless but you appear to be using their experience to support your assertions(?)

.
Your Gemaire is much better than mine in Tampa, FL. The Gemaire in Tampa, FL is mainly a parts/unit seller- most of the time I am educating them on parts I need, tools and or systems.
I prefer R.E. Michel as a distributor (there more diverse in refrigeration).

What I am saying again is a majority of leaks can come from installation and or service error, not following best practices- no way to put this in a percentage. I used the shrader valve as an example and also the entire system should be checked for leaks as the overall leak practice.

What techs dont do (follow through) is they find a leak in the evaporator coil and stop there. Thats not good or best practices. Check the entire system. TEST!



Hopefully this OP will find a intelligent diagnostics person;then determine options.
* Final tip is make sure your getting an ACTUAL weighed in amount of refrigerant i.e R22 (what you should be charged- tech should be using a refrigerant scale) if your just trying to get by for the summer before next steps of finding the leak or new system.
 
#20 ·
Per centages are somewhat useless IMO.

Everyone has leaks in different areas.

I always put some leak detector soap or spit on schraeder valves once I remove my hoses.

Does not help that the caps are useless plastic on a lot. I replace them with brass ones a lot of the time.

Service valve caps if not properly sealed or tightened can be nuisance leakers.
 
#22 ·
I carry a few bags of brass caps. I'm always finding cracked plastic caps, or deteriorated o-rings. It's the first place the OP should check. Although, I doubt it's actually there, since so many people have checked this system, I'm sure at least one of them looked at it.

Cheers!
 
#3 ·
Simple fact: If you have to keep adding refrigerant, you have a leak! The leak can only come from three sources - the condenser, the evaporator or the lineset. 99% of leaks come from the evaporatorr coil, 9% from the condenser and less than 1% from the lineset (provided it is in a protected location).

You need a new HVAC service to isolate the leak and fix it or replace the offending component.
 
#8 ·
What reference data are you sighting these percentage leaks from. As a RSES member and certified tech we talk about leak identification all the time and best practices to determine leaks. We never have narrowed down specific areas relating to percentages i.e. evaporator this percent or condensor this percent: - RSES has membership in the thousands!:vs_cool:

Thats a very definitive statement you made about leaks- make sure you can back it up scientifically not opnion-ated.
 
#2 ·
Is it possible it has leaked that much freon? Yes, of course it is.
But you will need to obtain a set of HVAC gauges in order to know where the system is now.


If your system leaks "enough" freon, the low pressure switch will tell the compressor not to start.


But there are quite a few other reasons you might not get cool air from your AC.


You can try this (very basic test).....


Turn the system on cool and then go outside to the outside unit and look for the cooper pipes coming from the unit (usually going to the ground). There should be two. The larger one should be quite cool. If one is hot, the compressor is at least working more than likely. If one is really cold, the compressor and inside unit are at least doing their basic functions.


Is air coming from the vents with good pressure or is it weak (possible leak in the attic ?
 
#4 ·
If it cooled really well for one night then it has not lost a lot of R22 since last year.

I suspect the compressor may not be running or you have some other problem. Running it low of freon several times can damage the compressor as it loses oil and can freeze up and have liquid refrigerant slugging back to the valves.

You may want to get a tech to check it unless you have a electrical meter ( clamp on amp meter ) to see if the compressor is running. Plus the freon also needs checking.

At the age it is now I would not spend a lot of $$ repairing it. R22 is very expensive and going obsolete.
 
#5 ·
Thank you for the suggestions.

I turned my AC back on to investigate temperature of the lines (I haven't had it on in about a week) coming out the bottom of the compressor. I could not get the compressor fan to turn on.

I've checked the fuses, the programmable thermostat, the breaker boxes and the wire connections along the thermostat-furnace control board-compressor run and everything looks fine.
 
#7 ·
As suggested above, it may not be running due to a signal from a low pressure switch that disables the condensing unit if the refrigerant charge is low. I don't know how comfortable you are around these things, however you can manually engage the contractor (switch that energizes the fan and compressor. It will be a small plastic piece that is spring loaded and the default position is up. It will have many wires attached from the top, bottom and sides. Some newer contactors cannot be manually energized given your system age I am assuming you have one of the older ones. When energized it is pulled down to supply power to the necessary components. Turn off the power at shut off near the condenser to familiarize yourself with the component you are looking for. BE CAREFUL OF THE CAPACITOR (USUALLY BIG SHINY ROUND THING WITH WIRES ON TOP) IT CAN STILL GIVE YOU A PRETTY NASTY KICK EVEN WHEN THERE IS NO POWER! You can put on a pair of gloves and manually push this down. If you don't want to use your finger you can take a screwdriver and wrap the end of the screwdriver with electrical tape just to insure you don't short anything. Once you comfortable turn the power back on. If the fan and compressor engage this is most likely your issue. VERY IMPORTANT: BE CAREFUL, YOU CAN BE INJURED OR KILLED. SECOND IF YOU ENERGIZE THE COMPRESSOR AND SUDDENLY RELEASE IT DO NOT RE ENGAGE RIGHT AWAY. Give it at least 5 minutes before you attempt to do it again. Lastly if it does engage do not allow it to run for more than a few seconds, just long enough to confirm it is functioning. Holding the suction line (the big one) with your other hand to feel for a change in temperature cold is obviously what you are going for. Running the unit low on refrigerant will damage it.

All that said you may want to look seriously at replacement. No matter where the leak may be located, that system is old and not worth putting a lot of cash into IMO. You can get a much more efficient system and not have to worry about the constant issues year after year. You can get away with replacing the offending component, but who knows how much life that old system has left in it. You can do expensive repairs and then have to replace anyway or you can just replace.
 
#6 ·
I could not get the compressor fan to turn on.
Now, I don't know much about this but I can assure you that's significant. Turn the unit on, go outside. If the fan is not turning take a small stick or long screwdriver and give the fan blade a spin.

If fan starts running, replace the fan motor capacitor (about $10).
 
#9 ·
50% of my leaks are service valves that were never back seated or sealed properly.

5% are poor bubbly or missing silfoss welding on service valves.

20% evaporator coils with way too thin copper.

15% condensor coil leaks

10% miscellaneous leaks:biggrin2:
 
#24 ·
Thanks for the advice, @supers05. Luckily the weather has been manageable so I can take my time and go about troubleshooting logically. The AC unit disconnect has been pulled since I noticed problems.

I'm testing capacitors right now as well. There are 2 caps in outside AC unit. One is very old and I can't determine the type. My guess is a dual run capacitor but most of the markings have worn away.

I will attached pictures of 'the situation' I have going on here a little later today.
 
#27 ·
This is for sure frustrating! So, I do air conditioning repair in St. George Utah which I know is a completely different climate than yours, but was running into the same problem. It all boils down to the fact that you've got a leak. And because they can't seem to find it, I think the uncomfortable and expensive reality is that you may be looking at a complete replacement. That's what we had to do at our house after 5 years of dealing with the mysterious leak. I had to swallow my pride and call a bunch of different HVAC companies, but no one could find it. Sorry, but I think you're looking at replacement.
 
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