sealed heating system

[D-R]

I've read that changing radiators on a sealed heating system is not as straight forward and a normal system. Does anyone know how it should be done? Thanks.

[Turtle]

I assume that by "sealed" you mean a heating system heated by a combi-boiler. The method is mush the same as changing a radiator with a conventional system EXCEPT bear in mind that the system is under more pressure than a standard system and that after draining the system you will need to repressurise the system to the same pressure as it started at. There should be one or two filling valves at the boiler together with a drain cock and a pressure gauge. Make a note of the pressure before you start, drain the system, change your radiator and then refill the system to the same pressure using the filling line.