Update on mixer tap/shower attachment for bath

[MM]

I thought I'd hold off ordering anything until after everyone is back from the Christmas/New Year break, so this morning I enquired at two separate places this morning, the local family-run bathroom supplier; and Plumb Center in Spalding.

Both told me the same thing independently of each other: Water regs prevent swapping out two separate taps for a mixer tap/shower where the cold water is at mains pressure, which mine is. Apparently, once the mixer is installed, when the cold and hot are turned on, the high pressure cold water will overwhelm the gravity-fed hot.

Two solutions: One is to fit a pressure reducing valve in the cold feed, but the Plumb Center chap said this would have to be screwed right down to minimise the pressure.

Better (both suggested this independently): Run a new length of copper pipe from the cold water tank in the loft to the bath and cap off the existing mains-pressure cold supply to the bath. NB: The cold water tank currently only replenishes the copper cylinder in the airing cupboard. Disadvantage: The new gravity-fed cold feed to the bath would mean that the bath would take ages to fill. Not sure how much of a disadvantage that is, although I will say that it DID take ages to fill a decent bathful at a relative's house over Christmas. They have gravity-feed. Only mains pressure to the kitchen cold tap.

Finally, the Plumb Center bod was very helpful, spending a good five minutes going through the options. he said one thing I'd need to be aware of: Getting the old taps off is a dickens of a job as one has only minimal space on the underside of the taps.

MM

[Mentalguy2k8]

I had a similar problem with my kitchen mixer tap, I was advised to fit a one-way valve to the hot side because when I used a hosepipe, the (mains) cold water was pushing the hot back to the tank and out of the overflow outside when the hosepipe "stop" valve was on and the taps fully open.

But would it really take longer? Unless your hot water is above scalding or you take very cold baths, you wouldn't need more than 50% cold water so with the (gravity) cold running at the same rate as the (gravity) hot, they'd both take the same amount of time at worst, surely?

[Tim Watts]

There's a better solution that that:

A pressure *equalising* valve - has two waterways:

16711

Not cheap though.

I thought lots of "mixer" taps presented hot and cold right at the end of the nozzel to avoid this back pressure problem - or maybe that's just kitchen mixer taps?

And something will be siezed... Get a proper tap spanner, it will help.

[Terry Fields]

Water regs say that I have to run the flexible pipe for the shower head through a hole in the soap dish to prevent water from the bath getting back up the shower. It also means you can't use the shower head to get water up your whahoola to rinse the soap off. That is, Water regs might make sense, but sometimes only sort of.

If you can run 22mm pipe from the tanks to the bath/shower, especially if you avoid elbows and bend the pipe instead, this can significantly add to the flow-rate to both bath and shower.

[MM]

Well, sure, but running a new pipe from the loft to the bath is not an "instant replacement" of just the individual taps for a mixer tap/shower, which is what I thought the job would be. Good job I asked and was patient to wait until after the hols, because I had a mixer tap/shower attachment lined up on Amazon and it was 20 quid cheaper than B&Q. No worries, this was only going to be a temporary thing anyway while I recover from my op. I actually prefer a bath and hate showers! (But I can't have a bath for at least ten days after the op.)

MM

[harry]

Or fit a check valve (non-return) on the hot water pipe.

[Brian Gaff]

I was just thinking that. Actually, surprised nobody has invented a mains cold powered pump that will transfer extra pressure to the hot so although it would not be as fast as the mains, it would be faster than the gravity method.

OK should I rush out and patent it now do you think?

Brian

[Mentalguy2k8]

Worth a try.. I prefer showers and don't use baths much but I reckon I use

2/3 hot water to 1/3 cold water in a bath, so it doesn't matter how fast the cold comes through, it's always going to be the hot that takes longest.

[SteveW]

Google "Venturi Shower"

SteveW

[SteveW]

through a hole in the soap dish to prevent

the shower head to get water up

sometimes only sort of.

As our shower is gravity fed and the cold tank forms an air break, I'm not going to get dirty water back into their mains, so they can sod right off with their ridiculous regs on short shower hoses; and non-return valves that'd strangle the flow completely.

SteveW

[polygonum]

through a hole in the soap dish to prevent

the shower head to get water up

sometimes only sort of.

avoid elbows and bend the pipe

But all you'd have to do is fit a longer shower hose. (Yes - you could obviously re-route it avoiding the soap-dish arrangement. But the longer hose is a very reasonable thing for anyone to do - especially as a 2m Lidl one is cheaper than a 1.5m from many other sources.)

[MM]

I've just seen this:

work...

MM

[MM]

Kinda!

This is what I bought yesterday from Wilkinson for £12.50.

as ugly as a dead dog, but I tested it and the hoses stayed on the taps. As an stop-gap whilst I get over the op it'll do.

MM

[Grimly Curmudgeon]

Be aware of the stupidly small bore size on many shower hoses.