How to drain system to replace kitchen sink and taps.

[Kawazukli]

Hello,

I am thinking of fitting a new kitchen sink and could do with some advice about draining parts of my system.

Starting with the cold side. The sink is right over the rising main. The rising main pipe comes up to a stopcock, after which there is tee piece, one side of which leads off to supply the house and the other goes to the kitchen sink tap. Am I correct in saying that the only thing fed by the mains supply is the ballcock which delivers water to a big tank in the roof? I am thinking that if I close the main stopcock and open the kitchen tap I will have drained enough of the cold side of the system to allow me to disconnect the kitchen tap so that I can replace the sink and fit a new tap. Is there any chance that any part of my boiler is fed direct from the mains pressure side of the system, my central heating boiler does not deliver instant hot water,it uses a copper hot water tank?

Now for the hot side. If I can stop water being delivered to the hot water tank (using an isolating valve which I think I have), then drain the hot water by opening all the hot water taps is that all I need to do to replace the hot water tap on the kitchen sink? I am a bit frightened here that I might somehow break by boiler by draining water out of it, could that happen?

Am I correct in thinking that water in the boiler and radiators is isolated from the hot water that comes out of my taps? Is the only way that water can get into the boiler via a small header tank in the loft and the only way it can get out of the boiler via a special drain valve on the boiler (or via a radiator pipe if that is disconnected).

I don't want to do anything that will break the boiler, is there anything I am missing that could mean I damage my boiler?

Thanks in advance.

 

[kirkgas]

Your thoughts are correct, just make sure the hot and cold stop running at the kitchen taps before you disconnect the pipes, also clear everything out from under the sink, wrap an old towel round the pipe underneath when you disconnect you will get a little water out, but it always looks more than it is,

 

[jtsplumbing]

Be a good time to fit service valves under the sink wile the water is off, once fitted then you can turn your water back on, and take as long as you need replacing the taps, not always the easiest things to replace