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

American Museum of Natural History - New York, NY
Custom fabricated 30" high velocity air eliminator installed to solve noise problems in the existing system.
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.
Silence is Golden (Yellow) for Berners-Schober
“The pumps are much quieter as is the circulating water
Kansas State University - Manhattan, KS
Following the installation of numerous smaller units on campus that met all expectations, a separator upgrade was proposed for the central plant.