I agree with Klem. Weather should be moderating to more average winter temps. Watch your system and see if it behaves like it use to. If not, get a Trane Comfort specialist out to check your system. I am concerned though about the previous visit. If freon was just pumped in without finding and repairing a leak, then you are just wasting your money and can expect more trouble in the future. Trane condensers with electronic demand defrost usually perform quite good in cold and harsh winter weather. IMO This post was edited by tigerdunes on Fri, Jan 31, 14 at 15:57

It's probibly either colder than the pump is desighned to operate in or the pump hasn't been able to recover from a frost up. Switch to aux/emerg heat and see it that helps. If not,call your service man. If yes,leave it on aux until sun defrosts coil then switch back to normal heat. Technicaly,it shouldn't do that but many do it anyhow. If it becomes a presistant problem,stay on emergence heat until this ice spell is passed and hvac contractors catch up.

The OP didn't mention anything about cost in their inquiry but rather seemed interested in the advantages of this setup. So, the 803 or 8321 and TAM7 is a good combination and a nice balance of comfort/economy. This setup will overcool to dehumidify to an extent. With Comfort-R enabled this works well in controlling indoor humidity WHEN the systems are not oversized. Since they aren't buying a "top of the line" system, the TAM8 and ComfortLink II thermostat may not be worth it to them. To get much of the full benefits of these thermostats, the full communicating system (20i and TAM8) is required. They will however obtain the dehumidify on demand function with the XL900 thermostat. I was not expecting this to be an unreasonable upgrade charge -- perhaps it is, but the OP did not mention it (of course perception of cost/benefit is subjective). It's up for them to decide now. Tiger as always I do respect your opinion and don't necessarily disagree with you on the (sometimes) unreasonable upgrade charges and whatnot. There are good, competent, and honest dealers out there that don't charge an arm and a leg for nicer systems that benefit the HO. I think the OP is working with one of them compared to what you see elsewhere. There is a jump in cost for two stage systems across all brands. We are talking two complete change-outs here (albeit based on the descriptions they don't sound "overly" difficult -- absolutely no way to know for sure from here, though). I know you disagree, but it's all good with me and I hope it is with you. Differing opinions are good sometimes, right? It is ultimately the OP's call. My own personal experience with communcating 2-stage systems (not just Trane) is that they do provide comfort and control advantages that justify the upgrade cost in many cases. Look forward to seeing how this progresses. Ditto on the load calc! This post was edited by ryanhughes on Fri, Aug 16, 13 at 18:59

What thermostat model do you have? And no outdoor sensor for locking out HP? Tell us your system model numbers. You will do no harm setting thermostat to emergency which will utilize nat gas furnace as well as bypassing your heat pump. Not the way it should be but certainly will work. The short cycling of your furnace is not normal. This should be looked into, perhaps an upgrade to a better and correct thermostat. I can make a recommendation but only until I know your system's components. IMO