Sizing of TXV.

Empire_2

Is it straight 10 ton or staged? 5/5 7.5 /3.0? Usually a larger air handler will have 2 circuits with 2 5 ton condensers or something along thoes lines.

Mike T.

Techman

Sizing of TXV

Hay Guy's.Just curious,on a 10 ton{120,000}Air Cond.system,should you use a 7.5 ton TXV or a 10 ton TXV

Techman

TXV sizing

Hi Mike T.This is one compressor,with unloaders,and one TXV.

Empire_2

OK,....10 ton valve is correct Because.....

When running at full load the compressor is pumping out its 10 ton capability. Depending on which unloader you have (either hot gas bypass or suction cut off) As the load in the building drops the unloaders (Unload) the compressors total capacity by a certain percentage. Let's say it's 25% of the total capacity. You now are running at only 75% of total capacity. The 10 ton valve will still be fed and will act more like a large dehumidifier to bring down the remaining load in the building.

Mike T.

Empire_2

Techman

What type of compressor are you working on? Does it have the brass unloaders on the cylinder head? If you need adjustment manuals, I have them and would gladly forward them so you have them in your library.

Mike T.

Techman

TXV sizing

Mike T. The compressor is a Carrier #06D,with unloaders on the heads[2] .Thanks, I would like to recieve the literature that you have.But, how?Regular or e-mail?

Empire_2

Techman

I will post it here, but give me your E-Mail and I will send it that way to. I am not a pro when it comes to this stuff but I will try. M2112@adelphia.net Drop me a line and I will return the compressed folder on the capacity control.

Mike T.

Techman

Mike T.

Just finished downloading unloader info,THANKS,Hope to return the favor someday.I kneeded help to download the stuff, I'm just learning this computer.

Empire_2

Yea,...Computers are not my strong side.

Sometimes I think that I am the only one that has a hard time with this thing. I learn new things every day so I hope you could read it ;-) That info is nice to have. I find myself pulling it out just to adjust the unloaders from time to time. I save everything for situations like this. Good Luck Techman. Any Q: drop a line and if I can help I will.

Mike T.

Techman

TXV Sizing-R-22 A.C.

Back to the original question!The Sizing of the TXV is based on the pressure drop across the valve.All r-22 TXV's are sized and labled based on 100psi press drop across the valve so a 10 ton TXV is 10.2 tons at the rating of 100 psi pressure drop across the valve.At 200psi pressure drop across the valve, the valve is now rated for 14.4 tons. The 7.5ton TXV at 100psi pressure drop is rated for7.4tons, but at 200psi press drop the 7.5ton TXV is rated for 10.5 tons. On a 72-75* day, the suction press will be 60-65psig and the hi side will be 175-185psig,that is a 120 press drop across the valve.On a 90-95* day,the suction press will be65-75psig and the hi side will be250-300psig .that is a180-215 press drop across the valve.The principle is just like an oil nozzle,raise the pump press from 100psi to 150psi and the oil output goes up.

Empire_2

TXV

The expansion valve has only 1 Job, to control super heat. I think in your question, you have a great point. I think it would be based on average ambient temp for different areas of the country. To large of a valve would cause "hunting" and to small would "starve" the Evap. I think Eugene would like to take a stab at this .

Mike T.

Techman

TXV Sizing

Mike T. Alco, Sporlan and the other makers of TXV's have "extended capicity charts" giving the different tonnages for different pressure drops across the valve.

Techman

TXV

Mike T, all manufacturers of txv's have "extended capicity charts" these are based on the press drop across the valve,so like you said ;different ambient's around the country give different hi side pressurers thus different pressure drops.