This service valve is compatible with all non-potable expansion tanks, including Calefactio HGT series, Amtrol Extrol &
Radiant Extrol series, B&G HFT series, Watts EXT series and others. It is designed to simplify expansion tank
replacement/re-charging and filling/draining the system. HGSV12 is a simpler version of the Webstone 41672 valve and does
not have the supply line connection.
