will this hydronic circuit work?

ron

my current install was done with circulators in the cold input side of boiler and they pump into the expansion tank (which is located where the 4900 air separator is in pic below). I need to replace some valves and was wondering if I move things around according to this pic below (moving circulators after the air separator and pumping away from the expansion tank, and maybe put zone valves on supply side?) will it all work [better?] ?

hot_rod

yes, try not to pipe the circulatory off a tee like that, if the both could run at the same time It’s called bull heading Use a tee and ell

ron

can you draw or link a pic showing what you mean by using a tee and ell?

the hydrostat on the boiler is supposed to de-energize the viridian circulator when the indirect calls for heat.

ron

also would like some clarification on bullheading . Does it simply mean to cause or induce a [reverse] flow that is undesirable?

If so, i'm curious if my current setup has the same possibility although I am pretty sure both circulators will not run at the same time. here is pic of existing setup



is this what you mean be tee and L ?

hot_rod

yep, do the same at the boiler return

JohnNY

Hmmm. Are we pumping into the boiler? Is that high efficiency unit or a standard cast iron boiler?

Zman

Be sure the circs have check valves.