Mixer Tap and Banging Noises

[napalm78]

We've just had a new bathroom suite fitted. As part of this we now have a basin mixer tap and a new single hole basin where previously we had separate hot and cold taps.

There are two problems with the tap:

1) Flow when the hot only is turned on full is barely a dribble. Previous hot tap was fine i.e. decent flow rate. Plumber says it's due to small pipes within the tap itself i.e. nothing he can do. Is this likely to be true, and what can i do about it?

2) If both hot and cold side of the mixer are turned on, the water is stone cold, as if only the cold was on, which is odd, and also the amount of flow with both hot and cold on full is LESS than the max flow achieved with cold only full on. My feeling is that with both on full, some of the cold is going back down the hot supply, and that something should have been fitted by my (seemingly reputable) plumber.

It seems that the valve arrangement for separate taps (before new suite) shouldn't just simply be the same as it is now.

I would think that the whole point of a mixer tap is to mix scaldingly hot water with cold to make warm, but item 2) above means it's cold when you try this, hence no point in having a mixer tap.

I'm going to get in touch with my plumber to check, but i want some back up first!

 

[napalm78]

I forgot to mention...

With both taps full on, if you turn the hot off slowly, at a certain point you get quiet banging/rattling of system, and at another a single louder bang as the hot tap closes of the supply to the tap.

For a new installation this is really annoying

 

[tomy]

depends on the pressure of your hot water if it is tank fed the pressure will be a lot lower than the cold tap and that is why when you have hot and cold on together it only comes out cold and yes if your flow was better before on the hot tap it probably is the tap itself restricting the flow and there will be nothing you can do about it, All you can do is take the tap apart and check there is no muck it it but I doubt that very much.

 

[napalm78]

Hot water is tank fed, and as we're talking about a bathroom tap, we're upstairs, so not much pressure head. The annoying part is that it was fine before we changed the bathroom! Surely if it is down to small pipes entering the mixer i wouldn't be the first person to have this problem, and taps would have been redesigned so it wouldn't happen!

Are there certain types of mixer that are less likely to suffer from this? E.g. ours is a single hole with 2 tap handles, but i have seen ones where you have only one tap lever that you move left/right for temperature and up and down for flow control. Are these any less likely to have a problem?

Anyone any ideas how to solve this?

 

[JohnD]

Do you mean the hot water is low pressure (from the tank) and the hot water is high pressure (from the mains)? Then a bathroom mixer isn't the right thing to use (kitchen mixers are different).

If it's a single hole tap it probably has riduculous little pipes like pencils underneath, so it's true, with the low presure, you won't get a good flow.

Sorry.

Probably looked nice in the showroom.

I suppose you could think about a shower pump arrangement, but in your shoes I'd buy a new basin and ordinary taps, and put it down to experience. Did you choose it yourself or was it recommended by anyone you can blame?

 

[napalm78]

Nobody to blame but me, unfortunately.

The basin/taps are nothing special, and only looked cheap in the show room, rather than nice as such. Just a million times nicer than the 1960's style suite in our 1950's house!

My wife isn't going to be impressed - i had told her that there was just the tiling to do now, then it was all sorted...