Thanks for the reply, Ronnatalie. I've never seen one either. My questions is coming from a regular HAVC system with the compressor and it's heat exchanger coil in the outside unit. There the goal of the heat exchanger is to cool down the superheated Freon after the compression cycle. The cooling is done by a blower pushing air thru the heat exchanger. Instead of the blower the heat exchanger coil could be submerged in water and therefore cooling down the Freon. Now, if I have both, blower and heat exchanger for Air/Air and a Liquid/Air heat exchanger in series I could choose which one is cooling down the Freon. This should work for a regular HVAC. I just donÂt know how a Heat pump with its changing direction of Freon would work with this idea.

It is a federal law to reclaim refrigerant properly. It cannot be released into the atmosphere intentionally, so they would have to recycle it. I question the $700 figure. You need to get more estimates, because the repair cost sounds high--I don't care how much refrigerant they have to recover. And no, you don't want to reuse contaminated refrigerant in a system. It needs to be clean, new refrigerant.

Never a bad idea to replace the copper lineset, but oftentimes it is very difficult if not impossible (think about condo complexes where the lineset often runs between walls of other condo units). If reused properly (i.e., blown out with nitrogen with a deep vacuum) and the proper size, they don't always have to be. The leak is most likely not within the lineset because it is one solid piece throughout. 2 stage units provide an advantage in terms of humidity control; however the 16i and Carrier models (and any brand using an unloading Copeland scroll compressor) run at around 80% capacity on low, so there isn't a huge turndown for the price premium. While I prefer Trane equipment over Carrier myself, both manufacturers make excellent equipment with comparable warranties, and both should do a fine job if installed properly. I think in this case, if looking at 2-stage units, the Carrier system with the Infinity control is the better system simply because the Infinity control does a much better job controlling the system than does a standard 2-stage thermostat such as the 802. Looks like the Carrier dealer finds that your home needs a 3.5 ton system (or 4 ton if 2-stage) while the Trane dealer is quoting slightly larger equipment. Something to bring up to the Carrier dealer. However if 3.5 tons is indeed the proper size, and a 4 ton is installed -- while it would not be a major issue in terms of comfort or efficiency -- the 3.5 ton would certainly be better in terms of humidity control and efficiency because it would not be short cycling as much on milder days. The single stage Comfort 15 with v/s air handler and the TP-PRH control will also do a good job with dehumidification without the added cost of 2-stage, but with the rebates and the Infinity control I think the Performance 16 is the better choice if going the Carrier route. I realize I haven't exactly convinced you to go with either system, but know that either one should do a fine job if sized and installed properly. The installer is key. All in all, I think you'll get the most out of the Infinity system.

I also have a TETCO heatpump that is suddenly resetting on the lowpressure lockout. I do have iron in my water and if possible would like to talk to you about how you have been maintaining your heatpump. Thank you!