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.

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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.
Commercial Gallery
Spirovent® is now the basis of design in many specifications by the top consulting engineering firms for new construction.
University of Missouri - Columbia, MO
The University of Missouri, Columbia is home to the second of the world's largest Spirovent® combination air eliminator and dirt separator.
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Spirovents have been installed in many new and existing industrial HVAC systems.