defective central AC system?

[afr]

In 2015, I had an American Standard 13 seer 30k Btu AC condenser(R-410A) and same Trane evap coil on existing Rheem furnace(was only a few yrs. old) in my 1580 sq. ft. townhouse. The existing line set was flushed with R-11,evacuated and pressure tested; otherwise my basement ceiling would've had to been torn apart. One year later refrigerant leak due a leaking schrader valve needed to be replaced.Following year(2017) refrigerant was 1 lb. low again and dye pack was added along with the refrigerant. Checked for leaks one month later at evap coil,connections,condenser,valves and compressor. Found no leaks using UV light and leak sniffer. All good. Fast foward to 2019 and dye was found at evap coil(condenser was good). Coil was replaced/brazed in(free of charge), pressure tested to 130psi pumped into a vacuum of 340microns,released charge and added an extra 6oz. Ran fine. Two months later a failed 40/S capacitor failed and was replaced and system was cycled afterwards. Now its 7/2020, we're in the middle of a heatwave(outside Phila) with afternoon temps in the mid 90's w/dew points also mid 70's. We usually keep the thermostat at 72-73 F and the system usually keeps temp until much later in the day, when the temp on thermostat won't dip below 74F. Does the sound like a totally defective system? Or just the typical garbage made in Mexico these days?

[Bazooka Joe]

One year later refrigerant leak due a leaking schrader valve needed to be replaced.

Wasn’t a Schrader Cap installed and snuggled up initially? Did you have a cap on the Schrader initially? Leaking Schrader value could also fall under improper initial install brazing practices ( overheating the area or not taking precautions to protect the service valves from overheating during brazing ) at the service valves. Is that where your talking about?

[afr]

One year later refrigerant leak due a leaking schrader valve needed to be replaced.

Wasn’t a Schrader Cap installed and snuggled up? Did you have a cap on the Schrader initially? Leaking Schrader value could also fall under improper initial install brazing practices at the service valves. Is that where your talking about?

That I'm not sure.

[comfortdoc]

We are currently at or above design conditions for a large part of the day. It is typical for a properly designed system to run continuously and lose a little ground. Does the house feel comfortable?

[Bazooka Joe]

That I'm not sure.

Residential warranty should be 10/10 compressor and parts. Did you register or whomever registered your system after install. Not being registered chances it falls to a base warranty of 5/5.

[afr]

We are currently at or above design conditions for a large part of the day. It is typical for a properly designed system to run continuously and lose a little ground. Does the house feel comfortable?

Yes, the house currently feels comfortable.

[afr]

Residential warranty should be 10/10 compressor and parts. Did you register or whomever registered your system after install. Not being registered chances it falls to a base warranty of 5/5.

Compressor and equipment-10 yr. warranty;labor-2 yr. warranty(installer)

[kdean1]

Most manufacturers use capacitors from Mexico or China. They use them because they're cheap. But they can fail in a year or two. I prefer capacitors made in the US that have a 5 year warranty.
Lot's has been written about Amerian customer's "Walmart" mentality. They want stuff cheap so manufacturers have to keep prices low. And customers play contractors against each other looking for the lowest price.
Many here have stated WE would prefer equipment that lasts longer but is not as efficient as what the regulations now require. Then we wouldn't have to explain to customers why their 7 year old heat pump lost a compressor, or in your case, why it needs a repair each year.

We share your pain.

[afr]

Most manufacturers use capacitors from Mexico or China. They use them because they're cheap. But they can fail in a year or two. I prefer capacitors made in the US that have a 5 year warranty.
Lot's has been written about Amerian customer's "Walmart" mentality. They want stuff cheap so manufacturers have to keep prices low. And customers play contractors against each other looking for the lowest price.
Many here have stated WE would prefer equipment that lasts longer but is not as efficient as what the regulations now require. Then we wouldn't have to explain to customers why their 7 year old heat pump lost a compressor, or in your case, why it needs a repair each year.

We share your pain.

Sounds reasonable. But how about compressors and especially coils not manufactured or assembled in Mexico or China. Does that even exist? Personally, I blame the manufacturers for the race to the bottom.

[kdean1]

Sounds reasonable. But how about compressors and especially coils not manufactured or assembled in Mexico or China. Does that even exist? Personally, I blame the manufacturers for the race to the bottom.

If the public would pay for higher quality instead of shopping based on price, things would be different.

[NETWizz]

In 2015, I had an American Standard 13 seer 30k Btu AC condenser(R-410A) and same Trane evap coil on existing Rheem furnace(was only a few yrs. old) in my 1580 sq. ft. townhouse. The existing line set was flushed with R-11,evacuated and pressure tested; otherwise my basement ceiling would've had to been torn apart. One year later refrigerant leak due a leaking schrader valve needed to be replaced.Following year(2017) refrigerant was 1 lb. low again and dye pack was added along with the refrigerant. Checked for leaks one month later at evap coil,connections,condenser,valves and compressor. Found no leaks using UV light and leak sniffer. All good. Fast foward to 2019 and dye was found at evap coil(condenser was good). Coil was replaced/brazed in(free of charge), pressure tested to 130psi pumped into a vacuum of 340microns,released charge and added an extra 6oz. Ran fine. Two months later a failed 40/S capacitor failed and was replaced and system was cycled afterwards. Now its 7/2020, we're in the middle of a heatwave(outside Phila) with afternoon temps in the mid 90's w/dew points also mid 70's. We usually keep the thermostat at 72-73 F and the system usually keeps temp until much later in the day, when the temp on thermostat won't dip below 74F. Does the sound like a totally defective system? Or just the typical garbage made in Mexico these days?

To answer your question, you do not necessarily have a lemon in that each problem was a different problem, and fixing the problem properly likely yields a system good as new. It could run without further issues for 10 years OR perhaps it breaks tonight while you sleep.

At any rate the RX-11 flush is pretty common and a good practice when installing a new system on an existing line-set especially if changing from an HCFC to an HFC refrigerant OR doing a burn-out clean-up.

The schrader valve leak completely explains the loss of a pound of refrigerant the first year. Most likely it was caused from the installers cooking the service valve because they are often morons who have never wrapped a valve in in a wet rag or similar, yet think nothing of taking an oxy acetylene torch to it for brazing hot enough to turn the copper red-hot, yet somehow they do not care about the rubber-like service valve gaskets. You are lucky if it is only the schrader valve that leaked and not the actual service valve itself. If one schrader was fried, I would replace them both. I would probably have the next tech sniff under the service valve caps to verify.

***

At any rate, replacing the coil is unfortunately a common task as well, and you got a new coil, so that issue is resolved.

Capacitors also do not last long with regard to Chinese and Mexican ones. The default manufacturer's brand is often something like Tong Feing (China) or Genteq (Mexico). Personally, my system was installed in 2015, and I cannot remember if I replaced the cap in 2018 or 2019, but I went with one made in the USA with a 5 year warranty.

***

You mentioned the system is NOT keeping up like it once kept up.

What is the delta-t from where the filter is to an air vent? i.e. Using a thermometer, what is the air temperature at each location? Has it changed since last year?

My first question for you would be, are both fans constantly running inside and outside? You don't see any icing up on one of the copper lines near the inside unit do you?

I would also inquire when was the last time the air filters were changed? I cannot tell you how many calls we see where the systems cannot breath and loose a LOT of BTU.

Lastly, how does the outdoor unit's coil look? Is it dirty? When was it last cleaned, and how was it cleaned?


Lastly, if you want to check something else, outside there are two copper pipes going to the outdoor unit. A skinny one just under half an inch (usually 3/8") and there is another copper pipe that is usually about one inch (really 7/8" is the most common).

If you have a thermometer (i.e. a digital meat thermometer), you can take the temperature of both of those copper lines and report it back to us here if you like. The thermometer tip would need good contact like being tapped to the copper with a piece of electrical tape or similar and if you want a little foam tucked around it for a few minutes to get as accurate a reading as you can.


These numbers would help us give you some input though we cannot really diagnose a system without seeing it, sometimes we see something obviously wrong and will advise you to get a technician out to address an issue. If the outdoor unit has never been cleaned, it has been five (5) years, and I would suggest you call a technician to come out and perform that service, but make it clear you expect the top removed and a full inside-out cleaning with at least a mild coil cleaner. This is because it is of little value to you if another person spends 5 minutes hitting the outside with a garden hose in that it might help, a real professional service goes above and beyond that into the realm home-owners should NOT do because of the danger of electrocution and injury... but a good tech can really clean that coil. To complete the maintenance, you can reasonably expect the condensate drain be vacuumed and perhaps some pan tablets placed into the inside unit.

I would surely make sure the outdoor coil is clean AND the indoor filter are cleaned BEFORE the tech starts checking charge. Then, you if you want you can ask the tech if you have a piston or a TXV. If he says piston, you should see the tech taking a temperature reading inside (with something that is not an infrared thermometer) and outside with a thermometer. (Inside it will really be a psychrometer, which measures the humidity too to determine the sensible and latent heat load). If the technician says you have a TXV, then he or she likely has no need to go into your house to get a temperature reading just to charge the unit. At any rate after all that, outside you should see the tech take an outdoor temperature regardless, and the tech will at that point hook up the gauges AND some type of temperature probes to the copper lines. Often times these look like jumper cable clamps and have a little cable going back to a thermometer or digital gauges. Some new ones are a wireless sensor.

Simply put properly charging a unit one must take into impact the type of system you have, environmental factors (inside and out), pressure, and temperatures.

Charging a system properly or determining its charge is NOT merely like putting air in a car tire.

If you hire someone who merely connects some hoses from a manifold gauge set, next time get a different technician because that person is a hack. Now if a system is severely low or has a major problem like a restriction, a seasoned tech can immediately spot if something is WAY off just by connecting gauges. For example if you have an R-410a system and typical pressures are maybe 110 PSI to 135 PSI low-side depending upon all of the above and more, and the system is showing 70 PSI, there is a HUGE problem.

Just the same if you touch the copper pipes, and the big one is not sweating (i.e. colder than dewpoint) and it feels like maybe 70 F or 80 F... definite problem that does not take gauges to know there is an issue. If the skinny copper pipe is so hot you can barely touch it... HUGE problem!

By HUGE problem, I do not necessarily mean expensive like replacing a coil. I simply mean it warrants investigation and action that only a tech can perform. It simply would not be correctable by a home-owner. For example a HOT skinny copper line (liquid line) could be as easy to fix as a detailed cleaning of the outdoor unit, but again level of cleaning is NOT a task for a homeowner in that to do it properly the top needs to come off and there are electrical and other injury hazards like should the motor start while being removed.


I hope that makes sense. You can always spot a pro from a hack, BUT a professional with his hands, eyes, and ears can often tell immediately what a problem is not even needing all of the tools of the trade.

^^^ All of this and more are the real job and why you need a seasoned tech. After five (5) years, somebody best be cleaning the outdoor coil and not merely slapping on some gauges and adding some Freon like filling a car tire.

When you DO next see a tech, ask the tech for some BRASS caps over the schraders. You might even ask if he wouldn't mind putting a dab of Nylog on the cap rubbers. He will know what that means.


At any rate your system not keeping up could merely be from lack of maintenance. I see it everyday on systems a lot younger than five years too. You would be AMAZED how much better a system will work when the outdoor system is professionally cleaned and the air filters changed. Oh, and when you get filters, if you have those standard 1" thick ones, do NOT buy the pleated MERV 10 or Honeywell or 3M 9000 or whatever it is they sell. You want the cheaper filters that you can see light through because they allow for more airflow than the expensive ones. Tech tip... Using some masking tape, you can tape around the borders of the air filters to keep blow-by unfiltered air from going around the filter. This would REALLY keep the indoor coil clean and free of debris.

[afr]

To answer your question, you do not necessarily have a lemon in that each problem was a different problem, and fixing the problem properly likely yields a system good as new. It could run without further issues for 10 years OR perhaps it breaks tonight while you sleep.

At any rate the RX-11 flush is pretty common and a good practice when installing a new system on an existing line-set especially if changing from an HCFC to an HFC refrigerant OR doing a burn-out clean-up.

The schrader valve leak completely explains the loss of a pound of refrigerant the first year. Most likely it was caused from the installers cooking the service valve because they are often morons who have never wrapped a valve in in a wet rag or similar, yet think nothing of taking an oxy acetylene torch to it for brazing hot enough to turn the copper red-hot, yet somehow they do not care about the rubber-like service valve gaskets. You are lucky if it is only the schrader valve that leaked and not the actual service valve itself. If one schrader was fried, I would replace them both. I would probably have the next tech sniff under the service valve caps to verify.

***

At any rate, replacing the coil is unfortunately a common task as well, and you got a new coil, so that issue is resolved.

Capacitors also do not last long with regard to Chinese and Mexican ones. The default manufacturer's brand is often something like Tong Feing (China) or Genteq (Mexico). Personally, my system was installed in 2015, and I cannot remember if I replaced the cap in 2018 or 2019, but I went with one made in the USA with a 5 year warranty.

***

You mentioned the system is NOT keeping up like it once kept up.

What is the delta-t from where the filter is to an air vent? i.e. Using a thermometer, what is the air temperature at each location? Has it changed since last year?

My first question for you would be, are both fans constantly running inside and outside? You don't see any icing up on one of the copper lines near the inside unit do you?

I would also inquire when was the last time the air filters were changed? I cannot tell you how many calls we see where the systems cannot breath and loose a LOT of BTU.

Lastly, how does the outdoor unit's coil look? Is it dirty? When was it last cleaned, and how was it cleaned?


Lastly, if you want to check something else, outside there are two copper pipes going to the outdoor unit. A skinny one just under half an inch (usually 3/8") and there is another copper pipe that is usually about one inch (really 7/8" is the most common).

If you have a thermometer (i.e. a digital meat thermometer), you can take the temperature of both of those copper lines and report it back to us here if you like. The thermometer tip would need good contact like being tapped to the copper with a piece of electrical tape or similar and if you want a little foam tucked around it for a few minutes to get as accurate a reading as you can.


These numbers would help us give you some input though we cannot really diagnose a system without seeing it, sometimes we see something obviously wrong and will advise you to get a technician out to address an issue. If the outdoor unit has never been cleaned, it has been five (5) years, and I would suggest you call a technician to come out and perform that service, but make it clear you expect the top removed and a full inside-out cleaning with at least a mild coil cleaner. This is because it is of little value to you if another person spends 5 minutes hitting the outside with a garden hose in that it might help, a real professional service goes above and beyond that into the realm home-owners should NOT do because of the danger of electrocution and injury... but a good tech can really clean that coil. To complete the maintenance, you can reasonably expect the condensate drain be vacuumed and perhaps some pan tablets placed into the inside unit.

I would surely make sure the outdoor coil is clean AND the indoor filter are cleaned BEFORE the tech starts checking charge. Then, you if you want you can ask the tech if you have a piston or a TXV. If he says piston, you should see the tech taking a temperature reading inside (with something that is not an infrared thermometer) and outside with a thermometer. (Inside it will really be a psychrometer, which measures the humidity too to determine the sensible and latent heat load). If the technician says you have a TXV, then he or she likely has no need to go into your house to get a temperature reading just to charge the unit. At any rate after all that, outside you should see the tech take an outdoor temperature regardless, and the tech will at that point hook up the gauges AND some type of temperature probes to the copper lines. Often times these look like jumper cable clamps and have a little cable going back to a thermometer or digital gauges. Some new ones are a wireless sensor.

Simply put properly charging a unit one must take into impact the type of system you have, environmental factors (inside and out), pressure, and temperatures.

Charging a system properly or determining its charge is NOT merely like putting air in a car tire.

If you hire someone who merely connects some hoses from a manifold gauge set, next time get a different technician because that person is a hack. Now if a system is severely low or has a major problem like a restriction, a seasoned tech can immediately spot if something is WAY off just by connecting gauges. For example if you have an R-410a system and typical pressures are maybe 110 PSI to 135 PSI low-side depending upon all of the above and more, and the system is showing 70 PSI, there is a HUGE problem.

Just the same if you touch the copper pipes, and the big one is not sweating (i.e. colder than dewpoint) and it feels like maybe 70 F or 80 F... definite problem that does not take gauges to know there is an issue. If the skinny copper pipe is so hot you can barely touch it... HUGE problem!

By HUGE problem, I do not necessarily mean expensive like replacing a coil. I simply mean it warrants investigation and action that only a tech can perform. It simply would not be correctable by a home-owner. For example a HOT skinny copper line (liquid line) could be as easy to fix as a detailed cleaning of the outdoor unit, but again level of cleaning is NOT a task for a homeowner in that to do it properly the top needs to come off and there are electrical and other injury hazards like should the motor start while being removed.


I hope that makes sense. You can always spot a pro from a hack, BUT a professional with his hands, eyes, and ears can often tell immediately what a problem is not even needing all of the tools of the trade.

^^^ All of this and more are the real job and why you need a seasoned tech. After five (5) years, somebody best be cleaning the outdoor coil and not merely slapping on some gauges and adding some Freon like filling a car tire.

When you DO next see a tech, ask the tech for some BRASS caps over the schraders. You might even ask if he wouldn't mind putting a dab of Nylog on the cap rubbers. He will know what that means.


At any rate your system not keeping up could merely be from lack of maintenance. I see it everyday on systems a lot younger than five years too. You would be AMAZED how much better a system will work when the outdoor system is professionally cleaned and the air filters changed. Oh, and when you get filters, if you have those standard 1" thick ones, do NOT buy the pleated MERV 10 or Honeywell or 3M 9000 or whatever it is they sell. You want the cheaper filters that you can see light through because they allow for more airflow than the expensive ones. Tech tip... Using some masking tape, you can tape around the borders of the air filters to keep blow-by unfiltered air from going around the filter. This would REALLY keep the indoor coil clean and free of debris.

Thank you all for your advice and especially NETWizz for the above. Its definitely not a maintenance issue as I keep on top of filter changes(1" Rheem FPR4) and outdoor unit. I did check the delta t previously but forgot the exact #. I'll recheck that and the above items you were so thoughtful to include.

[afr]

Just checked. The delta-t is 8 F Taken at 2 separate locations. 1-at supply plenum64.4F/return closest to blower fan72.1F and 2-1st floor register64.2 and return73.2F Averages to 8 F.

[Mr Bill]

Sounds reasonable. But how about compressors and especially coils not manufactured or assembled in Mexico or China. Does that even exist? Personally, I blame the manufacturers for the race to the bottom.

Well let me give you a little different prospective. The Homeowners are also responsible for the demise in the quality, they can own 2 Ferraris, have a 10,000 sq.ft. home, log cabin in the country or beach home, all kinds of nice cosmetics in the home, but "almost" everyone I run across, gets the deer in the headlights look when you give them a price for a new a/c and heating system, go figure! Most "not all" homeowners want cheap, or as cheap as possible, for us to stay in business, the manufactures have to build cheaper, so we can sell cheaper. So, the moral of the story is, everyone shares a little bit of the responsibility for a lot of things being built cheap in this country.

[NETWizz]

Just checked. The delta-t is 8 F Taken at 2 separate locations. 1-at supply plenum64.4F/return closest to blower fan72.1F and 2-1st floor register64.2 and return73.2F Averages to 8 F.

An 8 degree difference between supply and return is indicative of a major problem. Ideally, normal “good” numbers would be at or about 19 degrees difference. By major I do not necessarily mean you need a new system or that it will be super expensive only that it is not something you can fix on your own. It could be as simple as a “leaking Schrader” for example, but nobody here can diagnose it without seeing the unit.

Since your outdoor unit is cleaned as are the filters, this is tech territory. You probably don’t want to hear it but the possible causes are things like partial loss of refrigerant, restriction or metering device failure, or a week compressor for example.

At any rate, it’s time to get a pro to come over and diagnose the system. You don’t want to keep running it long term the way it is because it can freeze up the inner “Evaporator” coil, which among other things can make it hard to work on if it is a block of ice That air will not flow through. When the ice thaws, it can potentially make a mess not all going into the drain pan, which could cause property damage.

Additionally, a unit low low on refrigerant or with a restriction is not getting enough quantity or volume of refrigerant circulating in the system. Specifically, a term a tech would use is to say the superheat is too high, which means the evaporator is starved for refrigerant.

The problem is that when this situation happens, there is also not enough refrigerant going back to the compressor in the outdoor unit to adequately cool the wi dings if that motor. Some units get so hot they actually cut out on thermal overload opening their windings. When this happens, they may or may not ever re-close and run again. Either way too high a superheat can damage a compressor.


****

If it were me and I weren’t a tech, I would shut the system off at the thermostat and leave it off until a tech can come out and check it.

One thing you might do is go outside and touch that bigger of the two copper lines going back to the condenser... it’s the insulated one with foam on it. If it is not in the 50’s as in like maybe 54F but rather in then70’s or 80’s that is a huge sign you likely have this high superheat condition I am talking about above.



Generally, in most parts of the country if you pull back a little of the foam it will start sweating because a 54 F cold surface it will sweat... this is because on a 90 F day with say 70% relative humidity is well below the dew point... water will condense on it from the outdoor air the same as it condenses on glass of iced tea. If you want to know the dew point in your area it is easiest just to look it up on a weather website that tracks weather and humidity and lists it.

In my area the dew point right now is 72. That means I am best not cooling the house to 71 because the windows will sweat as may other areas I cannot readily see.

[afr]

An 8 degree difference between supply and return is indicative of a major problem. Ideally, normal “good” numbers would be at or about 19 degrees difference. By major I do not necessarily mean you need a new system or that it will be super expensive only that it is not something you can fix on your own. It could be as simple as a “leaking Schrader” for example, but nobody here can diagnose it without seeing the unit.

Since your outdoor unit is cleaned as are the filters, this is tech territory. You probably don’t want to hear it but the possible causes are things like partial loss of refrigerant, restriction or metering device failure, or a week compressor for example.

At any rate, it’s time to get a pro to come over and diagnose the system. You don’t want to keep running it long term the way it is because it can freeze up the inner “Evaporator” coil, which among other things can make it hard to work on if it is a block of ice That air will not flow through. When the ice thaws, it can potentially make a mess not all going into the drain pan, which could cause property damage.

Additionally, a unit low low on refrigerant or with a restriction is not getting enough quantity or volume of refrigerant circulating in the system. Specifically, a term a tech would use is to say the superheat is too high, which means the evaporator is starved for refrigerant.

The problem is that when this situation happens, there is also not enough refrigerant going back to the compressor in the outdoor unit to adequately cool the wi dings if that motor. Some units get so hot they actually cut out on thermal overload opening their windings. When this happens, they may or may not ever re-close and run again. Either way too high a superheat can damage a compressor.


****

If it were me and I weren’t a tech, I would shut the system off at the thermostat and leave it off until a tech can come out and check it.

One thing you might do is go outside and touch that bigger of the two copper lines going back to the condenser... it’s the insulated one with foam on it. If it is not in the 50’s as in like maybe 54F but rather in then70’s or 80’s that is a huge sign you likely have this high superheat condition I am talking about above.



Generally, in most parts of the country if you pull back a little of the foam it will start sweating because a 54 F cold surface it will sweat... this is because on a 90 F day with say 70% relative humidity is well below the dew point... water will condense on it from the outdoor air the same as it condenses on glass of iced tea. If you want to know the dew point in your area it is easiest just to look it up on a weather website that tracks weather and humidity and lists it.

In my area the dew point right now is 72. That means I am best not cooling the house to 71 because the windows will sweat as may other areas I cannot readily see.

Went outside and the insulated copper line was cold(unsure of temp)and sweating a bit. Outside temp of 84F with a dew point of 70F. Checked the coil and no signs of ice. FWIW, some of the foam insulation is frayed and some of the copper line is slightly exposed.

[NETWizz]

You checked the inside coil right? The outside coil never ices (unless it is a heat-pump that has a bad defrost board).

How cold was the copper pipe? Was it colder than 60 F?

At any rate, an 8F split needs to be investigated

[comfortdoc]

What did you use to measure the vent temperatures?

[kdean1]

You checked the inside coil right? The outside coil never ices (unless it is a heat-pump that has a bad defrost board).

How cold was the copper pipe? Was it colder than 60 F?

At any rate, an 8F split needs to be investigated

Never say never. Frost does indeed START at the evaporator but I've seen ice all the way back to the compressor.

[afr]

You checked the inside coil right? The outside coil never ices (unless it is a heat-pump that has a bad defrost board).

How cold was the copper pipe? Was it colder than 60 F?

At any rate, an 8F split needs to be investigated

Yes, I checked the inside coil by taking the front panel off. Do I need a clip-type thermometer to check the outside, insulated copper pipe? If so, I'll have to get one. Not sure if it matters but it is a 13 SEER unit.