Which controller?

[Selidor]

As my panels are about 40m from the thermal store, I'm planning to put a (pressurised with 1 coil)) tank "outside" next to the panels, and then transfer the hot water in "batches" to the indoor store as necessary. (using 16mm copper)
The outside buffer tank would also supply the pool heat exchanger once the indoor tank was up to temperature.

My current problem is that I can't seem to find a controller that mentions a buffer tank.
Would I be better to use 2 simpler controllers, one for the panels and buffer, one for the buffer (pretending it's a panel) and the indoor store?

Any advice gratefully received!
  Adrian

[Justme]

I think with a bit of jigging the SR868C8 controller will do the job.

It can move heat from one store to the other based on store temps.

[Selidor]

Thanks, I hadn't come across this one.
After a quick look I think it would as you suggest do the transfer bit, but not the whole setup.

[pj]

I use a Resol BS Plus to do precisely what you describe (well almost - I have a buffer tank in the roof). It has dual channels, and recognises this as a standard arrangement. If you download the manual, I think it was "arrangement 2" - "solar system with existing store".

[Selidor]

Thanks PJ, I'll download the manual and have a browse.

[Ivan]

These are all the configurations possible by the OLD version of the Sorel TDC3 controller that Navitron sells (the new version can do even more!). Take a look at schematic 11. It's basically using the 'heat dump' feature to dump heat from Cylinder1 to Cylinder2 when the temperature of Cylinder1 exceeds a certain level.

If you want a three-pump system, so you can divert to somewhere else, you'll need the TDC5. In fact, you could do this simply with a cylinder stat on Cylinder2.