I am replacing my furnace/zone controls/dampers/t-stats, my contractor has proposed two options:
1) Lennox G61MP furnace with LZP zone contols and 2 digital tstats. They tell me that the tstats will be single stage because I can't run 2-stage stats on 2 zones with the LZP controls.
2) Lennox G61MPV furnace with a Harmony zone controls and two digital 2-stage stats. He says the only way to use 2-stage tstats is to install the Harmony zone board.
I am leaning towards the second option, as (from what I've read), using a single stage tstat on a 2-stage furnace greatly reduces the value/efficiency.
Also I have an existing Lennox A/C compresser (model HS26-060-2P) that I am keeping.
- does all of this sound correct?
- what type of tstats should I be requesting with the Harmony controller?
- should I use 2-stage tstats or "modulating" tstats?
- is it OK to use a variable speed motor with the existing A/C, or do I risk coil freeze?