The last meeting i had with the manufactures they told me that no mater what you do it is hard to get the oil that is stuck to the inside of the lines, cleaned out of there. I think you can vacuum for hrs. and it won't take the old oil out. Just my opinion but i would never reuse the old R22 lines. Later paulbm

call a local dealer. If you use too small of lines, not only will the performance be less, but it may void the warrantee. Most 410 systems need larger lines for maximum perfirnamce. Kinda like buying shoes 2 sizes too small. They may look pretty, but they hurt when they are used.

Run what you have. You don't need to buy a matching airhandler now. Most of the airhandlers now a days designed to run off either R-22 & R410A. When we as installers go to pick up the airhandlers, most of the standard units come with a flowrater/orifice designed to run with the older style R-22 outdoor units. If we're setting a higher efficient R-22 outdoor unit, we ask for a R-22 expansion valve that matches the outdoor units capacity, to put on the coil in the airhandler. If we're setting a even higher efficient R-410A outdoor unit, we ask for a matching R-410A expansion valve to be installed on the coil in the same airhandler. Reguardless of what refrigerant the outdoor unit uses, the airhandler will be the same. Don't let them fool you by saying there will be no more R-22 airhandlers available. If efficiency isn't as important to you as using what you already have, then don't worry about it. Your overall efficiency might not be a full 13 seer or whatever the outdoor unit is rated but it will work, with the proper expansion valve. IMO Hope this helps

If this is a heat pump, it's even worse to mismatch. The problem is the 13 SEER outdoor unit. Sometimes, for air conditioning systems, a 13 SEER coil can be mated to an older 10 SEER unit and be made to work with a TXV. Always best to have a matched system though. See link below for Carrier article (which actually states the SEER would be close to 12 SEER, but see the other problems associated). Here is a link that might be useful: Carrier article