Pump to or away from boiler?

Serge

Hey all: I was always told to pump towards the heat source (boiler) rather than away. Pumping away runs the risk of cavitation and ruining the pump. Is this still true?

Thanks.

Brad White_203

It is far more important to

pump away from your expansion tank. Once that is done, it matters little weather you pump to or from your boiler so long as the expansion tank is correctly placed to be connected just upstream of the circulator.

Now, many modern boilers have higher pressure drops so you want to pump into them. That is fine.

The old "cavitation" risk was once true, but most even water-lubricated circulators these days, run on up to 245 degree water. I would worry far less about that than connecting the expansion tank properly.