change refrigerant from R-22 to R-410A?

[faranzubia]

I am in climate zone 12, California. I have estimates to replace 30 yr old split HVAC, not including refrigerant lines. I think I remember info that R-410A cannot replace R-22, even if nitrogen to clean condensate? one bid w/ cheaper (night&day) system retains R-22 (currently the refrigerant in existing Lennox), another ($1,200 more, Trane system) includes cleaning the existing R-22 using lines. I would prefer to be environtment friendly and assure available supply of refrigerant in future. However, I am concerned R-22 might contaminate new system and that higher pressure of R-410A system would be more leak prone for old refrigerant lines. Replacing the lines would require opening wall/ceiling and extra expense. Comments or advice?

[iraqveteran]

Its been studied and the refrigerant lines do not need to be changed when switching refrigerants. Flush with nitrogen and roll on.

Definately consider the R-410A system hard. Its a wise choice to move to. Especially since your talking b/t Trane and Lennox. Night and Day once again.

If it were me, I'd go with the Trane. I'd go with the R-410A system as well. But thats just me.

[bmathews]

I've probably changed over 100 systems from R22 to R410 and have NEVER changed a lineset or used whatever crap they recommend to flush it with. And have no compressor failures or other related issues. If the lineset is too small for your new recommended system, then you need to change it. You'll get a bunch of varied opinions on here. I speak from experience actually doing it, not reading and listening to a bunch of worry warts.

[faranzubia]

consensus of 2, thanks to you both! Any other opinion?

[mark beiser]

I used to change the lines 100% of the time, per manufacturers requirements.

The manufacturers figured out that there were no more issues with old lines than with new lines, and that a little mineral oil contamination did nothing to the new system, and it was kinda BS to add upwards of $1000 or more to the cost of a new system due to a non issue, so the requirement was changed to a recommendation.

We pretty much only change them if they are the wrong size, the old system had a burnout, or there are other known or suspected problems with them.

One nice thing about R-410A is that the systems tend to use smaller line sets, so it is less expensive to run a new line set than it was for a high efficiency R-22 system. The size of the existing lines is more likely to be an approved size for an R-410A system than for a high efficiency R-22 system, the R-22 systems tend to require grande sized suction lines.