OK, not politics, a DIY question.
The flow on our shower (mixer, gravity fed) has been gradually reducing. I tried to look at it, and found it wasn't designed for easy access. It's buried behind the tiles. so **** it I paid a plumber. I'm now regretting it :(
He first suggested that it was probably the thermostatic mixer valve. He got me to order a new one from Bristan, and came back and fitted it.
No difference.
The next idea was the non-return valves on the inlet. He used something like a big Dremel to cut away the tiles a little, leaving a hole just big enough for access, but small enough so the decor plate covers it.
He told me it doesn't need the valves, and broke them out. I say broke - they came out in bits.
The next idea was to check the inlet. It's got filters on both sides, and the one on the hot side had some bits of bug in it. (A couple of wings, and what looked like the chitinous exoskeleton of a hymenopteran. I know more about bugs than plumbing!).
He replaced that one, put it back together, and all was well.
My wife even commented that it seems to warm up much faster than it used to.
But then a few days later, but only after we'd paid the bill, I turned on the cold tap in the basin next to it. It was hot.
It appears that the hot water is syphoning through the shower mixer, and back up the cold pipe. It's not enough flow for my worst fear - I recall a case a few years ago where a loft header tank got so hot that it softened and collapsed onto someone in the bed underneath, causing nasty scalds - but it's still wasting energy.
Now finally the question:
Should the plumber have known what the non-return valves are for? Should he come back and fix it? Should that be at his expense? The valves aren't much, but it'll take a while.
Thanks Andy