How are valves fitted and cast iron radiators sealed?

It is important with our cast iron radiators that no caustic plumbing compounds are used on any part of the radiator, its valves or connections (this can react with the iron, breaking down the sealing washers in both the radiator & any ‘O’ rings in your boiler or pumps). If any compounds are used then you must return the water to Ph neutral before operating the system. All radiator joints should be dry jointed, with PTFE tape wrapped around the valve threads for tightening. We would recommend the use of a thicker gas type PTFE tape on parallel threaded valves.