Paulo wrote:

Hello

I need to replace leaking solder joints and add a radiator to my
sealed system, which is fed by a combi boiler.
After reading various DIY advice website pages, they recommend that I
should contact a plumber for all sealed system work but state that I
can attempt this work if I had an 'open vent' system instead.
Is there major safety issues and additional working procedures
involved with sealed systems repairs? or is ok for an average DIYer to
tackle a sealed system without contacting a plumber?

Thanks
Paulo

Read below, Paulo, for a less nannyish approach to DIY advice.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html