I have a hot water tank, 3 header tanks in the loft and so I am assuming I am on an open vented system. I wish to replace a bathroom radiator with a wider one so will need to extend the existing pipework. I also want to tile around the pipework by drilling the tiles (for a neat finish) and sliding them over the 15mm pipes before attaching the radiator valves.
Can I isolate or turn off the water feed to the radiators to enable me to do this or do I need to drain the entire system? If so, how do I do this?