Patronbike-mine did the same thing last year. When it was in the 50s, I'd have to set it at 66 and as it got colder I had to increase the temperature to keep the room warmer. It never turned off when it was in the low 20s or lower. The thing I noticed is the unit would push more heat then it needed and not at the minimum.
The problem I believe is the air it's pulling in fluctuates to much. I'd measure the temperature and it was dropping 4 degrees in matter if minutes when it was in the 50s outside.

Hmmmm

What if I put a bath fan, duct and register all in 1 wall, sucking cold air from low near the floor, blowing up to where the head unit pulls air in?
It's not ideal but seems like it should work.

I guess it could be tested without committing by using a fan on the floor pointed up at the ceiling.  I'm afraid a fan just pointing to the ceiling won't really be effective enough but i'll try it tonight, going down to 4F.


Panasonic FV-05VS3 is approved for wall mount.

Ok so I pointed a fan up from the floor to the ceiling by the head unit.

Typical results WITHOUT the fan would be room temp: 65F on a cold day, with the set point at 70F.

With the fan, I turned down the set point to 68F (knowing it would be warmer than usual).  The room temp was 70F this morning (too hot for me).   Also, the temp on top of the head unit was exactly 70F.   It seems that the Fujitsu may be trying to stay in front of the heating needs by making it warmer than requested?   I may need to turn on this "high insulation" mode that other people have talked about.  Can anyone tell me how to do this?

I'm going to turn the set point down to 66F with the fan going, and see if the room temp stays at 68F. (That is pretty much where I want it anyway).

I don't mind a 2 degree difference as long as it is consistent through cold and more mild temps.  Seems like if nothing else, that helps...

I'm glad that helped some for you. Did it get rid of the short cycling?

With the constant "supply" of true room air temp, it doesn't seem to cycle much at all now (It would be interesting to see the hours per day that the compressor is on  now, versus before).

I have turned the set point down from 70F to 66F too, which may mean that is it supplying a more constant supply of slightly cooler air rather than on/off of hotter air (not exactly sure if these units modify the output air temp according to the set point... I think so??).

I'd be surprised if it is not more efficient running this way. It definitely seems more comfortable.