Recent content by nofossil

In my opinion the best control is to use a PV panel to run the pump directly. Sun goes down, pump shuts off, gravity drains the pipes to a small holding tank, which can be below an exchanger coil, or not. I haven’t done it, but I’ve seen it done. I had a batch heater once but your setup is...

Drain back solar systems have no pressure, because the water ( no coolant needed) drains by gravity ( after the pump shuts off) to a small holding tank. A pump pulls water out of the holding tank when the sun shines. If that’s the type you have you definitely don’t need a pressure tank