I have recently purchased a new home that has not been occupied. It was built in 2009. I have a Bryant AC (Model 340AAV). It is blowing but not cooling. The inside unit is a R-410A and the outside unit is a R22. I had a technician out on Friday and he said I needed to replace the Thermal Expansion Valve with a R22. I am utterly confused as it is my understanding this type of coolant has been phased out and is not as effcient as the R-410A. This is based on what I have read online so far.

I am not entirely comfortable with this company but before I have it re-inspected by another at $125 for the inspection I would like to have some additional info. First they want to charge $450 just for the value plus whatever installation/labor is. Second, I am not all that convinced that it will correct the problem. Last, why would they recomment what appears to be a downgrade of the 410-A system.

Can anyone provide some direction?

The indoor coil can be rated 410a (pressure wise) but the TXV or expansion valve must match the refrigerant used, in this case r-22. If your outdoor unit is r-22 than they are trying to match the efficiency of the units and the gas used.

If you have r-22 in the outdoor unit than they can pump down the r-22 into that unit and open the system to change the TXV

How did they come to figure out the TXV is bad? I know in technician jargon what symptoms it may show but are they saying it was mis-matched from the get go or just now the txv is going? That is pretty quick for a txv to go bad if it was matched properly in the first place.

Just curious if you want to explore it more. Also here are a couple of vids:

One on the R-22 vs r-410a debate and another on TXVs for your info:

R-22 vs R-410a head to head via you tube (http://www.thermal-medics.com/my-videos/r-22-vs-r-410a-head-to-head/)

TXVs via you tube (http://www.thermal-medics.com/my-videos/txv-tour-and-problems/)

A little knowledge goes a long way if/when you call someone else out for a second opinion

The tech said the original installer had a reputation of installing mismatched components, I have no experience with either company. Perhaps speaking with a few neighbors in the subdivision would yield some answers on that part since it was all the same builder/contractors. From what I understand the home has either not ever been occupied or if it has less than 90 days. It stood empty for 1.5 years, so the AC may have never actually worked at all. The tech didn't state specifically that the TXV is actually bad, but that the units did not match so it would have to be replaced. It may be the correct valve after all and simply have no freon. Can you leave an AC unit for 1.5 years and the freon still be good?

I did not get the "warm and fuzzy" from the tech that was here. He rattled off a bunch of jargon and I looked at the work order, the oem lables and the internet to try to figure out what he was saying.

Is there any type of test that a tech would conduct on a TXV to determine if it is working or not?

My other concern is the cost quoted, I see these valves online for nowhere near that cost. Due to the housing market where I am I got A lot of house for very little money so he may be assuming I'll just stroke a check and move on without research.

Often times the opposite actually happens.

1. Freon or whatever refrigerant you have in theory should always be in the system. The level should not change over the years because it is a closed system and used over and over again. Now that being said the level will change as techs hook up their gauges and 'take' a little with them each time and then of course if there is a leak then out it goes.

Diagnosing a bad TXV usually takes a little work. The pressures the tech sees are low on the low side and normal on the high side. It often is misdiagnosed as an undercharged (low refrigerant) situation. The tech dumps in gas and nothing changes on pressures. The tell is what is called subcooling.

If the tech took accurate superheat and subcooling readings then he would have seen a high subcooling (liquid backed up in the condenser).

Ok enough jargon - Is it possible that the installer put a mismatched air handler/txv in the home with an R-22 system. Yes, but that is a major FUBAR. Is it worth a second opinion, I would say yes.

I would not say anything about the previous diagnosis. Ask the tech some questions about superheat/subcooling and see where that gets you. Meanwhile you can get educated and know what they may be talking about.

There is nothing worse than a tech who can't explain in laymans terms what the fudge is going on. You can't tell if you are getting a line of BS or if they are just socially challenged.

Last, look at the TXV yourself and see if there is a discerable r-22 or r-410a written or labeled on it. Or run the part number and see what you get on the internet.

Good luck