Using Old Lennox Air Handler w/ R410A

[dow1236]

Currently, we have the following split system using the old freon - Heat Pump : Lennox HP26-042-7P (published SEER 14.65) and Air Handler Lennox CB31MV-51-1P. We live in Southeast Texas, where humidity removal is important, thus the 3.5 tn HP and 4 tn AH. These units were installed in 2000. The heat pump was damaged when the electrical service had problems (transformer) over a 12 hr period. The homeowners insurance is covering the HP replacement. They are saying that our existing air handler can be retrofitted with a new valve, the lines flushed, and a new Lennox XP14-042 installed using R410A. Because of the SEER rating of above 14, the insurance will match that number. The dry charge HP units that are available are all 13 SEER. From what I've been told, R410a operates at higher pressures than the old freon. My question - can the old air handler (designed for freon) handle the increased pressures required by the R410A? Will this flush kit clear all the mineral oil out of the AH coils and linesets? The companies that have given us bids (and have seen the installation) say that both units of the system need to be replaced. Any advice would be appreciated.

[toocoolforschool]

If they are paying you have nothing to lose but comfort. If I was paying I would change everything and get the ten year parts warranty and not look back.

[BaldLoonie]

IMHO, dry or at least install a matching coil to the XP14 in that air handler if it fits. If not, new air handler too.

[jtrammel]

They will never get all the oil out of the coil, it needs to be replaced. Home warranty companies don't care they just want it cheap. It ends up costing them more in the end but they don't see it that way. You need a new coil or air handler that matches the outdoor unit and preferably new copper line set that connects the two (it can be flushed but better to replace so you know it's clean).

[jtrammel]

You'd be better off with a dry charged r22 (freon) unit at 13 seer. If it springs a leak then you're looking at an expensive leak search, fix, and recharge bc r22 is getting really expensive with more new taxes in 2013 by the end of 2013 it won't be economical to recharge an r22 system its already very costly.

[beenthere]

About 6 months ago. I pulled out a HP 26 or 29, and put a R410A HP in its placed. Flushed the line set and indoor coil, put on a R410A TXV and its been running fine. Don't need to get all the oil flushed out.

And that isn't the first one I converted over to R410A. Haven't had a problem yet.