Trolmaster Humidistat Station (HS-1)The HS 1 from TrolMaster is used to control commercial dehumidifiers. Most larger commercial dehumidifiers have a low volt control option so the dehumidifier can be controlled by an external humidistat. The HS 1 works and is wired exactly like an external humidistat. The HS 1 is the best way to control your dehumidifiers by eliminating the need to control the high amperage inrush current associated with dehumidifiers.