Valves for heating systems and cooling systems; valves for use in introducing chemicals into heating systems and cooling systems; dosing apparatus for heating systems and cooling systems; dosing pots for heating systems and cooling systems; vessels, containers and chambers as part of heating systems and cooling systems; vessels, containers and chambers as part of filters and filtering systems used for maintaining and cleaning heating systems and cooling systems; water filtration apparatus and installations; water filtering apparatus; water treatment filters; filters and filtering apparatus for heating systems and cooling systems; magnetic filters for use in heating systems and cooling systems; air separation apparatus for heating systems and cooling systems; air purgers for use in heating systems and cooling systems.