Thanks integrated!

I've decided to stay put for now - stick with the Electric Mains Pressure and hope that I get 5 years before the next leak. Will probably have moved by then...

I do have a couple more questions though, if anyone feels like answering.

Is it permissible for a CWE valve to discharge uphill AT ALL? I can't see why not, but that doesn't mean a lot! At the moment, the outlet feeds downwards into a series of 15mm copper bends that end up in the TPR Valve overflow pipe, which drops through the floor then (slightly) downhill to the gully trap.

If I moved all the cold water in-feed valves under the floor, the CWE valve might have to exhaust slightly uphill (50-100mm?) into the overflow. Would that be an issue?

Also, is it required that there be a HWC cold water shut off valve located in the HW cupboard (before the Filter, PRV & CWE valve), or can it be under the floor?

Hi bowtieboy,

Thanks for the answers.

Am I allowed to ask why? Please!

Why no uphill flow from the CWE valve outlet? The cylinder is Mains Pressure, typically runs at about 5 bar, so 100mm of "head" is inconsequential, no? I can understand why no uphill flow from the TPR valve, as boiling water doesn't want to hit a slug of cold water on its way out, but this is not the same thing, as far as I can see? Is there an official reason / explanation?

Also:

all valves must be accessible.

What does 'accessible' mean in this context? 

My floor is wooden, over a crawl space. The access door is about 1.5m away. Is that not sufficiently accessible? Or, does it have to be accessible from within the habitable space?