Adapter cap for a fire hydrant, a fire hydrant and a method for remote monitoring an open-close status of a fire hydrant

An adapter cap kit for a fire hydrant comprising a hydrant actuation nut by way of which said hydrant is opened and closed by rotating said hydrant actuation nut, said adapter cap kit comprising:

• at least one reference part comprising a fixator for fixating said reference part to a hydrant housing of said hydrant, and
• an adapter cap, including
• a cap housing comprising a connector for connecting said adapter cap to said hydrant actuation nut, said cap housing comprising a cap actuation nut by which said adapter cap may be engaged, and said cap housing comprising a skirt part arranged to encircle at least a part of said connector, wherein a connector centre axis of said connector and a cap actuation nut centre axis of said cap actuation nut are arranged coaxially, wherein said connector and said cap actuation nut are made from a metal, and wherein at least a part of said skirt part is made from a polymer material,
• at least one open-close sensor arranged in said cap housing for detecting said reference part, and
• a wireless communicator arranged in said cap housing for communicating data from said at least one open-close sensor wirelessly to an external data system;
• wherein said wireless communicator comprises an antenna and wherein said antenna is a patch antenna.