Is it the tap or the vented hot water system?

[The Plumber Guy]

Hi all,

I've got a customer with an Edwardian bath/shower mixer which gives her water that's either too hot or too cold. The taps are quarter turn, so ceramic disks of course, but even I couldn't get the hot water to come out at a safe temperature. I'm wondering if this is down to a failure inside the tap itself or if it's difficult because it's on an unvented system and the head pressure is low. We had the same thing at home when I was (much) younger and it was really difficult to mix the water safely.

I don't want to change the mixer tap and have the same problem.

Cheers all,

Guy

 

[Burger]

Is it not a balancing issue? You might have the same as me, mains cold with gravity hot water, there’s a way to do it safely - TMV.

 

[Alan Wright]

If it were a balancing issue I would expect it to be running either too hot or too cold not too hot then too cold.

Could it be the mixer has an anti-scald feature and you really do have hot hot water or the anti-scale is faulty.

Try reducing the water temperature?

 

[Burger]

depends on how good all pressures are.

 

[Chuck]

I've got a customer with an Edwardian bath/shower mixer which gives her water that's either too hot or too cold

Has it ever worked correctly? What you are describing can happen if the hot and cold feeds are swapped by a careless installer.