Identify problematic mixer tap please

[andytw]

Hi,

Couple of questions.

Firstly can someone identify the brand of mixer tap in the pictures please.

Secondly has anyone had experience of selecting cold water but getting hot water instead. The water does eventually run cold. This is a new problem affecting 2 mixer taps in my son's house.
Taps will be a couple of years old. Other outlets at the property are OK. We are therefore suspecting the taps.

andytw

 

[muggles]

Judging by the word "hansgrohe" written across the top of it, I'd hazard a guess that it's a Hansgrohe branded one....

It sounds like you've got hot water creeping into your cold. What kind of hot water system does your son have?

 

[andytw]

Whoops. I hadn't seen the writing on the tap or visited. I just asked for some pictures.
I am pretty sure it is an unvented cylinder. I'll get another picture then we'll know for sure.
The house is a new build about 2 years old.

andytw

 

[Newboy]

It's possible that the hot and cold pipework are in close proximity to each other and there's heat transfer between the two. How long before the cold actually runs cold?

 

[andytw]

Here is an image of the cylinder.
I presume that as there is no cold water storage then all cold water outlets are fed directly from the mains ?
I understand re unvented cylinders so won't be touching it but if its the taps then....
Presumably if they print their name on a tap then it is a reasonable product ?

I considered pipe proximity initially but am told this is a new problem and that the water is very hot.

Plan at the moment is to wait until it is happening, it doesn't always, and then reach around the basin and feel the pipes.

andytw

 

[oldbuffer]

Looks like a Hansgrohe "Focus". Their stuff is expensive, but in my experience, very reliable. If the two problem taps have been working OK for two years, but have both suddenly malfunctioned, I think I'd be looking (as other have said) at an unbalanced pressure problem. Any unvented hot water cylinder and associated controls should be serviced annually by a suitably (G3) qualified technician. Such a service wouldn't be a bad starting point for the investigation.

 

[andytw]

We've moved on a bit.
A plumber from the original installers has taken a look and believes the problem is due to the thermostatic safety valve located under the bath.

andytw

 

[dilalio]

Blending valve? Seems a bit odd to have one of those and then a mixer downstream! Unless the hot is mixed under the bath and then a cold fed separately to the mixers. Are both mixers fed by this valve?

Do you have any details for the Thermostatic safety valve?

 

[andytw]

It looks very similar to one of these

http://www.screwfix.com/p/pegler-prestex-p402-15mm-tmv/96288

I don't know what the bath tap is and how it is plumbed without asking or visiting. Plumber said one of these had to be fitted to stop the bath being run at too high a temperature.

 

[jeff the gasman]

Blending valve? Seems a bit odd to have one of those and then a mixer downstream! Unless the hot is mixed under the bath and then a cold fed separately to the mixers. Are both mixers fed by this valve?

Do you have any details for the Thermostatic safety valve?

It's a building regulation mate.

 

[dilalio]

Blending valve? Seems a bit odd to have one of those and then a mixer downstream! Unless the hot is mixed under the bath and then a cold fed separately to the mixers. Are both mixers fed by this valve?

Do you have any details for the Thermostatic safety valve?

It's a building regulation mate.

Of course
Was having trouble painting a picture in my head!