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danamy72 · Aug 15, 2007, 07:01 PM

I have a new Payne brand 2 ton central air unit that was installed by my home warranty company, and after two months and after they sent out three different companies to try and fix my cooling problem, the last company decided that the original Carrier brand system that has been in my home for 26 years was not installed properly because it had a three ton coil with a two ton condensing unit. The warranty company claims that those parts were mismatched therefore my warranty with them is now void and they will no longer work on my a.c. My question is in 1980 was it common or "ok" to install a three ton coil with a two ton unit? I can't imagine that in 26 years none of the other owners of my home ever had a problem with it if it was really mismatched. Help!! I'm a single mom and I don't know anything about air conditioners!

acetc · Aug 15, 2007, 07:15 PM

This is done quite frequently, in fact Carrier now makes a coil to fit two ton to three ton systems (same coil) You can actually get better humidity removal with a larger coil and some times a higher efficiency,Mike
Did some one replace a three ton condenser with a two ton condenser at some time?
What problems are you having with the A/C?

danamy72 · Aug 15, 2007, 08:21 PM

The problem I am having is even with the new unit outside, I am still only getting mid to high 60 degree air coming out of the vents so by the end of the day it is 80 plus degrees in my house and the ac has ran all day. My house has plenty of insulation, and a two ton unit should be enough for my 1000 sf home. I just moved into the home in June, but from what I am told, it is all the original system that was installed in 1980 and nothing has been changed out until now. My home warranty co. sent a third company out to look at the system, and he told them that the coil was mismatched, that it would not have ran right with a 2 ton unit which is what they removed. But what they removed was a Carrier and replaced it with a Payne. So now that the last company they sent is telling them that my original parts were mismatched they are claiming they don't have to warranty the system. This company says that the cooling problem I am having is due to the coil being the wrong size. They say you can only go up a 1/2 ton or it won't work correctly. Dana

acetc · Aug 15, 2007, 09:01 PM

That is not so on the tonage, I was wondering if they put a smaller condensing unit on then what was there? Sounds as though they just want an excuse to get out of warranty responsibility. If they determined that due to the mismatch it will not work then I would tell them that it was their contractors fault by installing a condensing unit that their third contractor said would not work, both of these contractors were employed by them, so if it was installed with their knowledge that it would not work, then they should not have installed it, if the contractor that installed it according to them installed the wrong size unit then the insurance co. is responsible because they hired them, and they being professionals are suppose to know if the equipment they are installing is matched to the existing componets of the system. Take them to small claims court or at least threaten them to take them to court.

danamy72 · Aug 15, 2007, 09:31 PM

I have not yet actually threatened to take them to court over it, but I have claimed that it was their installers fault for not checking the coil to see that it matched, and they say that they just would not have installed the unit at all then. The only other problem that was found with my system is that there is a valve coming from the furnace connected to a drain that is leaking and it has leaked onto the ductwork directly under my furnace, and rusted it to the point that you can put your fingers through it, but at this point I don't believe there are actual holes in it except for the hole put in it by the last serviceman. He tells me this drain is clogged. Could this be causing my cooling problem? If the evaporator coil is not the real problem, what is? This takes me back to the same problem I had before they replaced the outside unit. Nothing has ever changed. It was my problem when I placed the claim, and it is still my problem now. The ac does not cool the house properly in temperatures above 85 degrees.

acetc · Aug 15, 2007, 09:53 PM

This coil and furnace being an old installation, there is a good possibility that it may have a dirty evaporator, if it had enough dirt wash off the coil to plug the drain line then that tells me it is suspect to being dirty.These evaporator coils collect dirt that gets through the filter and sticks to the coil because the coil is wet when in the cooling mode.
The coil is not easy to clean because it is best to remove the coil and wash it then reinstall it.
Bottom line is if the coil is dirty then it is not working efficiently or to full capacity.

danamy72 · Aug 15, 2007, 10:38 PM

The guy was actually checking for a dirty coil when he discovered that it was a three ton coil. He did not say that he found any dirt or excessive dirt on the coil that would cause it to run improperly. I hope you don't think I am trying to argue with your answers, you are being very helpful, I am just coming back with what they are going to tell me in hopes that maybe you will have a come back for me to give them the next time I speak with them. Thanks for your help. I'm just trying to learn enough to sound like I know what I'm talking about when I talk to them so they don't think they can take advantage of me. But are you saying that you don't think that should be causing my problem then?

hvac1000 · Aug 16, 2007, 03:16 AM

A 3 ton coil will work with a 2 ton unit no matter who made the items.
You need to calculate the correct charge by subcooling or superheat.if the service man does not know what superheat or subcooling is fire them and find someone that does.
In many cases it is easier and more efficient to have a thermostatic expansion valved installed on the inside coil. It will make sure the coil is fed the proper amount of refrigerant at all times.
Sounds like you could have a non condensible problem also. Did the service man pull a vacuum before he charged the system? Did he flow nitrogen during the brazing process? Did he leak check the system?

These are just a few of the problems people run into when using a home warranty company. The company does not want to spend any money to fix your problem correctly because they hire the cheapest service company. The cheapest service usually does not have a talented staff and this is the outcome of it all. Problems.

acetc · Aug 16, 2007, 07:54 AM

Finding a dirty coil is not what a service person wants to find normally because it is difficult to clean some times takes two people to remove the furnace in order to get the coil out. The service person will usually have a number of calls waiting on him so he does not want to get hung up on one call.
The coil is hard to see if it is dirty or not because by taking off the front panel you still can't see the under side of the coil where the dirt is.
The reason I am suggesting the coil is because it should work if the coil were clean. Good luck, Mike

danamy72 · Aug 16, 2007, 09:11 AM

I do have a TXV coil. They did have to come back and remove water from my system after the new unit was installed because the first company did not install something he was supposed to to keep the moisture out. They hooked it up to a pump that ran all night and then came back the next day and recharged the coolant. What is a non condensible problem? I'm not sure what pull a vacuum means or flow nitrogen.

hvac1000 · Aug 16, 2007, 09:53 AM

Originally Posted by danamy72

I do have a TXV coil. They did have to come back and remove water from my system after the new unit was installed because the first company did not install something he was supposed to to keep the moisture out. They hooked it up to a pump that ran all night and then came back the next day and recharged the coolant. What is a non condensible problem? I'm not sure what pull a vacuum means or flow nitrogen.

Non Condensibles= water/moisture/air or other impuritys that are not supposed to be in a refrigerant system.

Vacuum is required to remove the non condensibles.
Nitrogen gas is required to be in the copper line set when brazing is going on. Usually just a small flow. It prevents flake or other items from forming on the inside of the copper line set. The high temperatures required for brazing causes this.

J Costa · Aug 16, 2007, 02:52 PM

They probably did not install a line dryer that captures moisture and debris and it sounds like what they ran all night was what is called a vacuum for your a/c non condenseables means you would have moisture still inyour system that cannot be condensed in the compressor.

tech2k10 · Jul 29, 2010, 04:06 PM

Pulling a vacuum means evacuating the system of all of the air you breath. If you do not do that it can cause high head pressures, in addition, pulling a vacuum is the proper way to determine if a system has a leak or not.
Flowing nitrogen is part of a proper installation to provide an inert gas in the refrigerant tubing so as not to introduce copper scale into the sealed system which can clog filter dryers (if installed) or TXV or cap tubes.

tech2k10 · Jul 29, 2010, 04:12 PM

A Non-condensable proplem is when a system contains elements of atmospheric makeup .
Pulling a vacuum on the sealed system evacuates all of the undesired gases from the system.
It also is the best test for leaks.
If it will not hold a vacuum it will not hold under operating pressure.
Nitrogen flow is part of an installation process when brazing of the copper refrigerant lines is done to inhibit scale due to
Oxidation when the system contains normal air.
Scale can cause problems with filter/dryers cap tubes and TXV.

joestudenthvac · Mar 1, 2012, 01:20 PM

Nitrogen is a dry gas that we use to purge the system and is also used to pull out moister... a non condensable would be dirt or moisture that has been introduced to the inside of your system.. the fact the guy left the vacuum pump running there all night is an issue because it should take no longer than an hour or two to pull a complete vacuum unless the system has a leak or has a lot of moisture in it... when they swapped the system did they leave the lines open for extended periods without being covered did they install a liquid line filter dryer and are the people working on your unit competent... oh your warranty is invalid due to using mismatched parts but if you insisted that they mismatch the units then you are to blame for any issues steming from that

johnlewis692 · Jul 2, 2012, 12:59 PM

Hi,

My AC guy will be installing a Carrier Infnity 2 Ton Condenser, Infinity 96 heater
And a carrier 3 ton coil. I don't why the coil is 3 tons but he claims that this is the correct match up? Does this seem correct?

hvac1000 · Jul 2, 2012, 01:04 PM

Originally Posted by johnlewis692

Hi,

My AC guy will be installing a Carrier Infnity 2 Ton Condensor, Infinity 96 heater
and a carrier 3 ton coil. I don't why the coil is 3 tons but he claims that this is the correct match up?? Does this seem correct??

A 3 ton coil will work if the proper flow rater OR expansion valve is used. They should be installing expansion valves these days since they make the unit more efficient.

johnlewis692 · Jul 3, 2012, 07:25 AM

Is an expansion valve similar to what is ued on car AC?

Where is the expansion to be placed, insde the coil?

hvac1000 · Jul 3, 2012, 12:18 PM

Originally Posted by johnlewis692

Is an expansion valve simular to what is ued on car AC ?? Could be but different design parameters.

Where is the expansion to be placed, insde the coil??

On the liquid side feeding coil/sensing bulb goes on suction line between 10 and 2 o'clock.

wmr4cmh09 · May 21, 2013, 12:16 AM

I have an older carrier unit, but it had a new compressor in it. Plus the guy that came out put a newer set of coils on the inside unit. I don't know what ton it is but I think it's a 4 but not sure. Also the compressor blew on the outside unit a while back. How do I determine if it's a 3 ton or 4 ton? I can't tell by the writing on the outside unit. Also I think the trunk lines need to be reduced because there huge. If I reduce the trunk lines and put new ducts off the trunk line to new receivers this will help the air flow. But can you hook a 3 ton unit or 4 ton unit to a 2 ton unit? Please help me guys, in disabled and need some cool air.here is my email. [email protected]. Thanks. Will