I have several proposals for the installation of a new, more energy efficient HVAC system for my home. The company reps from Trane are telling me that they will need to install new refrigerant lines for the R410A because they can't remove all traces of R22 from the current lines. Lennox reps say that they can remove all of the R22 and use the current lines for R410A. Anyone know anything about problems with putting R410A into lines that previously contained R22?

The two key points on the line set issue is as follows; 1. is the line set the proper size to use for R-410a ( both liquid and suction?? ) 2. The old line set can be cleaned with a flush made by Nu-Calgon called Rx-11 flush to remove the mineral oil that the R-22 refrigerant uses.

If you are getting a new system get a new line set. How cheap do you want to get. Another thing. Your old lines set might not be brazed but silver soldered.
Silver solder does not hold up will with the increased pressures of 410.

You did not say the tonage of the condenser you are replacing but the Usually line set size is 3/8 and 3/4. Again this all depends on the condenser you are installing.

Sometimes the lineset are difficult to replace and very long so it maybe expensive to replace. If it is expensive to replace the lines a tech can easily flush out the lines.

But the only reason to replace the line is not because of R22 freon but because of the mineral oil that runs the R22 system in which a few drops maybe in the lines. Or the lines are the wrong size for your new system.

As the previous answer states, you can flush the old line set with the right flush and have no problems. As far as silver soldering compared to brazing, 15 percent silver is more than sufficient to withstand the pressures of the new refrigerant.

Our company has been replacing R22 system refrigerant lines for 6 years without ANY problems whatso ever! We remove the R22 equipment and then flush the existing refrigerant lines with dry nitrogen.The refrigerant lines are pressured with nitrogen to 250# of nitrogen and checked for leaks by valving off the low side gauge on the nitrogen regulator and then observing the high side gauge for pressure drop.(2 or 3 minutes.If no drop in pressure,which should indicate 1500#s or more,One can safely assume that the lines are leak proof.The nitrogen is then purged through the low side of refrigeration gages and evecuated.The high side valve is then opened on the new equipment and system is allowed to equalize.WE have had NO PROBLEMS with this procedure in 6 years of implementation.C. Cooper.

I am replacing a 2.5 ton system that uses R22 freon, with a new 3 ton system that uses the new R410a. I have had one contractor tell me the freon line needs to be replaced not only becaues of the R22 oil, but that the line needs to be bigger. I think I currently have a 1/4" line (not sure of the size). He said it needs to be 3/8". Does the line need to be bigger when using the R410a, over the old R22 freon?

Thanks

Sdh

Yes, 410A uses larger linesets.

I have the same question I am changing from a old 8 seer 2 1/2 ton system to a 3 ton 13 seer system the old lines 5/8 by 1/4 I've had two contractors tell me the lines don't have to be changed and 2 say they do who do I believe

If the new system uses 3/8 & 3/4" lines, as it probably does, your existing lines MUST be replaced. Failure to do so will void any manufacturers warranty do to failure to install the equipment properly.