Solar Heater - Draining


New member
Nov 13, 2014
Las Vegas
Purchased pool and solar heater with home. Solar heater has an older Pentair controller and valve. There is a check valve on the inlet to the solar heater once the diverter valve ports to heater, no other isolation installed. Seems like heater drains when valve ports to pool since water flows into pool and pump shuts off. I'm thinking it must have vacuum valve installed. Is there a need to add manual isolation valves and or manual drains to the system? Weather is Las Vegas wintertime and not frigid Midwest.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Welcome to TFP!

Isolation valves are very handy to disable solar when there is a leak, but aren't involved in winterizing.

Can you describe where that check valve is a little more carefully? If it is after the diverter and before the pipe goes up to the roof you might need to open up the check valve to drain the solar feed line.