R-410a in R-22 systems

I'm sure something would change.

I don't remember the name of it, but one of the basic gas laws says that the total pressure of any mixture of gasses equals the sum of the individual vapor pressures of each gas.

The vapor pressure of any gas depends on its density. Unless R-410a and R-22 have the same density, they most likely will not have the same vapor pressure.

You should be able find the information online you need to help you finish out this theoretical exercise. Personnally, I wouldn't even think of trying it for real, for if the resut is a sudden and sharp increase in system pressure, you won't be able to complete the operation without an explosion and the release of toxic gasses.

I could see the disaster if you changed all the refrigerant to R-410a, but what are your thoughts if it was only a few ounces of 410 in a 5 ton r-22 system?

A few months back, a client of mine had a couple of refrigeration units installed by some less-than-qualified technicians who wound up using the wrong refrigerants in the units (I don't remember which refrigerants were used). Both systems had to be vacuumed and flushed a couple of times with the correct refrigerants, because of a concern over the effect of mixing them. I don't know for sure what the effects would have been, but the client was not willing to find out through experimentation...

Charging about 10 ounces of R-410a into an R-22 system will cause the head pressure, suction pressure and evaporator temperature to go up. How much will be determined be the total charge of the system and the type of expansion valve, either TXV or Cap tube.

r410a is the ozone friendly "replacement" for r22.

it is incompatible with the mineral oil used in r22 systems, using a synthetic oil specific to the application.

its expansion and absorption characteristics are different as well, requiring a compressor with different expansion ratios, as well.

r410a requires smaller tubing, and different characteristics in the condensers, and evaporators, as well

bottom line: recover the refrigerant to a waste cylinder, and purge the oil as well. a commercial flush, such as r11 should suffice. evacuate, to ensure a clean system, and recharge both oil and r22

recovery of mixed gases must be to code, and routed to a licensed agent

http://www51.honeywell.com/sm/410a/about-us/az-story.html

I agree that the tubing is smaller for a 410 system, which is why my guess is that nothing would be affected in an r-22 system due to pressure temp relationship. But since this is a question that I can only guess at I am acceptable to being told that I am wrong. haha

YOURS IS THE MOST CRITICAL POINT.

Yosemite3 is correct, except R-11 is banned under the Montreal protocol. There are other flushing agents available.

Its actually " R11X" flush, an ozone friendly/ EPA compliant acceptable way to rid the old oil (but not in all applications). I believe NuCalgon makes it.

I recently encountered this same problem, except the tech added 3 pounds of R410a to a 2 ton R-22 system.

Don't have a problem purging the refrigerant gas, evacuating the system and changing the dryer, but what has happened to the mineral oil? Has it been ruined by the R410a, or will it be ok once the R410a is removed? Since the compressor is fully hermetic there is no reasonable way to drain the oil and replace it with new mineral oil.

Do you have precise knowledge of what will happened to the oil in this situation? Most of the comments I see above are guesswork which is fine, but wont stand up in a legal dispute.

If R-410a is added (by mistake) to an R-22 system, ALL effects are detrimental to the performance of the system designed for R-22, In residential cooling, R-410a operates at +/- 400 psig condensing while R-22 is 225 psig. It takes much more liquid R-410 evaporating to absorb as much heat as R-22 . The coefficient of performance (thermodynamic efficiency) of R-410a is lower than R-22 for typical home cooling.

Petroleum lubricating oils have poor solubility in R-410a so esther based lubricants are required.

R-22 is extremely stable in service. R-410a is EXTREMELY sensitive to moisture, flux, and decomposition by too much heat.

R-22 costs some $2/#, R-410a is >$10/#