Currently I don't seem to have any hot water getting into the hot water tank (CH OK). I've had a look and firstly does any one know what this box does:
From this box there are two pipes, the first to the CH (I think) and the second to half way down the hot water cylinder. Now this second pipe has a tap on it which is fully open. However the pipe is hot before the tap and cold afterwards, despite the tap being fully open.
Here's a little pic (sorry it's not perfect, I had trouble getting in there with my phone):
1) What's the white box thingy? Is the problem here?
2) Is there a blockage in the tap - can't think why - the tap hasn't been touched. Is it just pipes that are hot before the tap rather than the water inside them?
Any help gratefully received, lack of hot water not going down very well at present :-(