Valiant 831 - No hot water in Bathroom

[Glees7]

We haves Vaillant EcoTec 831 boiler.
Heating works but I think the radiators need bleeding.
Biggest problem is no hot water in the bathroom.

It will run to a luke warm temperature for approx 1-2mins.
Then runs cold.

Any suggestions on what the problem may be or how to test/fix it?

Thank you

 

[ianmcd]

Do you get HW at other taps say kitchen or utility room ? are your bathroom taps thermostatic mixer taps? does the demand light come on at the boiler when you run the bathroom taps ?

 

[Glees7]

Thanks

Yes hot water fine in the kitchen.
The bath tap is a mixer, not sure if it's thermostatic.
The boiler indicates that hot water is running and the temperature indicates that it's going up.

...??

 

[ianmcd]

sounds like your problem is your mixer tap and not your boiler, Identify the HW outlet of your boiler and then run the suspect tap , feel the temp of the HW outlet if it is a lot hotter than the water coming out of the suspect tap then the mixer tap is blending cold water in there (a very common problem )

 

[PlumbGas]

you have a problem with the tap cartridge not the boiler, if the boiler was at fault it would be the same at all hot water outlets,

 

[ianmcd]

As Plumbgas says , I just had to drag the information out of you ha ha ha