I got a new Rheem modulating furnace and thermostat about 6 weeks ago. Love it.
But in the process of recovery from night set back it does an odd thing (I think). It runs full speed for the first half hour or so to get toward the target temp at the target time. Then it throttles down steadily to finish up the recovery job. That's all fine. The odd thing is that after about 2 hours of run time the furnace ramps up again for a while. When I look at the thermostat I find the temperature has dropped a degree or two from what it was earlier in the recovery process.
For a system that can fine tune the amount of heat to recover and maintain, it seems odd to me that it can lose track of what it's doing by as much as 2 degrees! This "losing track" behavior never recurs in the maintain process for the rest of the day.
I asked my contractor about this a few weeks ago. He too thought it was odd and replaced the thermostat. No change. Still the same behavior.
So, is this "normal?" Sure doesn't seem to me like it should be.
Oh...one more thing. During the recovery, the +2 indicator may come on in the thermostat display, as described in the manual. But I don't notice a thing when it happens, and worse still, it STAYS ON even after the furnace is well into the modulating down phase. I am thinking that the +2 display is bogus, that it means nothing in a fully modulating set up. Right? Wrong?
Thank you for any comments.