Advice needed - water from shower when hot tap on

[Rob C]

Can anyone assist?

In our bathroom when I turn the hot tap on at our sink, water starts to come out of the shower head and there is a grinding noise. This just started recently and now happens every day, not all the time, probably 2 or3 times a day. we have a gas combi boiler. Is this something I should worry about or get checked?

We did get a new washer fitted to the thermostatic mixer bar a few months, but I don't know if it could be related to that.

any thoughts what could be causing this?
thanks in advance.

 

[Radioman]

What washer was replaced? What make model of shower mixer? a photo would help. Do you mean the thermostatic cartridge? Is the grinding noise coming from the shower valve?

 

[Rob C]

Thanks for getting back. A plumber put a new rubber washer in what I think is the non-return valve pack, so not the mixer cartridge itself. The washer was replaced in the right hand outlet section near where the mixer is fitted to the wall. The existing washer had deteriorated. The shower mixer is a Triton Luca thermostatic bar mixer. I cant place where the noise is coming from, sounds like the pipework behind the tiling, but could be the mixer bar. I will see if I can pin point it next time it happens. I have attached a video clip at...https://youtu.be/qofrPPOKhQQ

 

[king of pipes]

The repair is the place to start I would say the non return valve in the cartridge is stuck which is allowing water to pass when the shower valve is switched off and the hot tap is turned on

 

[king of pipes]

These may help