Are my minisplits modulating or short cycling?
Hello- first of all this site has been an incredible resource. I did most of my own research in adding 4 mini splits to my 1940’s home. It was primarily for AC and heat for the shoulder seasons as we really enjoy our 1 pipe steam heat (although older boiler). I went with 2x Fujitsu (not XLTH) condensers with 2 heads each. A 12k per floor (open kitchen area, top of stairs, attic playroom), and 7k in the master.
Home has been retrofitted with new windows, open cell in the rafters, blown-in in the walls, etc…so definitely on the tighter side for it’s age.
AC worked great during last weeks heat wave (Boston). We’ve now been dropping in to the 40s at night so I’ve been messing around trying to get the heat to be consistent. With a combination of adjusting the offset temp sensor setting, changing the set temp set point, and fan speed, it’s kept the house exactly at 71 over night and day. Upstairs might be 1 degree higher at times, and living room at the opposite end from mini split maybe a degree lower. I have 4 ecobee sensors positioned around so I can get consistent temp readings.
I’ve been reading in to short cycling, run times, and am not sure if I’m cycling or not. Sounds like this can only really be fixed on these units with a wired thermostat. The air temps at top of unit are maybe a degree higher than room temp- not a huge swing.
All the units exhibit this behavior:
Low cfm running all the time (sensing temp)
compressor kicks on
heat starts coming out/fan comes on
Heat for :30s-1 min
heat tapers off
back to low cfm
Repeat every 5-10 min.
From everywhere I’ve read,it seems they should be running for longer times?
There is a setting for “high insulation”, not sure I qualify for that.
Or is this just a drawback with mini splits during shoulder seasons?