Well, m WF series 7 has been oscillating between stages 7-10 the last few days.. Yesterday my usage was 80 kWh's all in heat stage 2. The unit has yet to kick in aux heat. I am glad it is keeping up but hope to get out of this cold snap soon. My loop temp is down to 27deg.
your post spurred me to go look at my Symphony. my incoming water temp is down to ~37 (deep earth ground temp is 55) and both of my units are using about 30kWh per day (so 60kWh total for house). I purposely oversized the field (only wanted to do it once) so the incoming water temp isn't surprising and because I have a dual unit system, ended up with oversized units for both zones (3 ton unit being smallest for WF7). Its been cold here in NJ but not earth shattering. Its interesting to see how much further my units could probably be pushed given your data points. I find they are running most of the day in stages 3-4 and middle of the night 5-7.
I have a single 5 ton unit on a retro install. 5 loops, 205ft long, 15 to 20 feet in the ground. I am happy the unit is able to keep up, just don't know how much longer and how much colder it could get before it isn't able to.
EWT is 38.5 here. That's after being without power for 20 hours and needing to bring the house from 52 deg back up to 70 deg. It took about 15 hours to come back to 70. My loops are oversized as well.
