Install the Spirovent® at the point of lowest solubility, which is the place in the system where the temperature is the highest and pressure the lowest. Note as well to always "pump away" from the expansion tank, never towards it.

Related Work

University of Delaware - Newark, DE
Following an on-site system review, the first two Spirovents were installed in an equipment room serving two residence halls with recurring problems.
Potawatomie Bingo Casino - Milwaukee, WI
Two custom fabricated 20" high velocity air eliminators.
Mercy Medical Center - Des Moines, IA
High velocity 18" combination air eliminator and dirt separator.
Eastern Illinois University - Charleston, IL
After having tried numerous other methods, the first Spirovent was installed in Carman Hall to deal with a long history of no heat calls and clogging valves.