Thermostat issue on Ariston WRc-NSF Unvented Cylinder

[harpss1ngh]

Hi I seem to have an issue with my thermostat on the Ariston WRc-NSF unvented cylinder.

The water coming out of the hot water tap is very hot, but with the cylinder knob right down it still seems to 'click on', causing my programmer to send a hot water demand to the Vaillant ecoTeEC 637 System Boiler. If I keep turning it down it does click off, until I have to turn it down further, while not making much difference to the water temperature. The boiler's flow temp is about 80 degrees, if that makes any difference.

If the cylinder stat is set all the way down (about a centimeter before the off position) and the water is already quite hot, does this indicate a fault with it?

How easy is it to replace, I can't seem to find a suitable spare. Can I replace it with the VR10 (NTC) one from Vaillant so I can set the temp with my controller? Is that easy to do?

Thanks in advance

 

[Dotty]

NOT A DIY REPAIR!

You need a plumber with a G3/Unvented ticket.

Please go to Gas Safe Register | Ensure your gas engineer is registered. or post a thread in the 'I'm looking for a plumber / gas engineer' section of these forums remembering to include your location. [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL]

Thread closed.