I got the Steca 301 and it works well with built in temperatures at
three locations (two used). It does not have adjustable differential
though. It has freeze protection but I do not use that (yet). It makes
no sense to do that on a drain down system, that I can see???

The Steca site displays a new model that will vary pump speed. They
report it will not be in N.America for another 6 to 8 months. I am
waiting for that one to appear as my pumps draws over 150W and it may
cut back on power after the initial water lift.

"Gary" wrote in message
...
Solar Flare wrote:
Which diff thermostat model did you order?

Nothing very exciting.
I got the old standby Goldline GL30

I looked at several others that had more bells and whistles,
including some nice
logging and reporting features, but decided in the end that
Goldlines long track
record for a reliable product was more important. If you got just
the wrong kind
of controller failure, your collectors might be in danger of
freezing.

I have a logger to track performance, so extra reporting features on
the
controller would just be icing on the cake.

Gary