I recently installed a brand new true 2 stage heatpump. At first, I tried using it it with a centralite pearl thermostat, but as it turns out that tstat can't effectively operate 2 stage compressor heatpump on the heat side, but can on the cool side.
So, I did some research and the Honeywell T6 Pro seems well supported by HE, so I picked one up, installed it, configured it, and created a Thermostat Controller to manage it so I could use some temperature sensors I've got scattered around the house to feed into the average temp.
What I'm noticing is the new tstat is seemingly always calling for second stage heat, even on relatively warm days like today where it hit 49F outside. I read over on this post that the Honeywell T6 Pro bases its calls for heat based off the cycles per hour setting. On these warm days the heat pump doesn't cycle all that often, so I'm guessing it's slightly more complicated than that (open to being told otherwise here - what the algorithm here is seemingly an enigma). Note my second stage is a compressor second stage, not electric heater strips or any other aux heating method.
So I guess what I'm trying to figure out is - does anyone else have this setup or something similar? My working theory is that the +2.0 default temperature offset that the HE's Thermostat Controller uses is too aggressive for the Honeywell and so it thinks it needs to run the heatpump at stage 2 heat to catchup. To test this I am going to try disabling the thermostat controller for now and see if I can get my tstat to just call for stage 1 heating during these warmer days and potentially switch into stage 2 if it needs. But I would love to hear if anyone has any familiarity with these tstats on 2 stage compressor heat pumps?