Shower problem

[pezza]

Hi,
I have a Bristan AR2 SHXMTFF mixer valve about 2 years old that works fine on cold water and maximum hot but keeps stopping and starting when the temperature is set anywhere in between.
I have removed the valve and cleaned the filters but the plastic cartridge is screwed in tight and metal spanners or sockets are mangling the plastic.
Anyone experienced the same problem or know whether it is definitely a faulty or scaled up cartridge?
A plumbers cost to clean the cartridge would be less than the cost of a new valve (£99) but if the cartridge needed replacing his total cost would work out more than a new valve which I can fix myself.
Thanks in advance for any advice.

 

[PhoenixServices]

Bristan have a 5 year warranty. Might pay to give them a call. They might come out or send a
Part, save you some money.

 

[pezza]

Thanks Phoenix. Wary about doing this. Their guarantee terms regarding regular maintenance and installation look very strict. I have been caught using this route with a shower pump that was faulty and still under guarantee. The engineer the company sent did not inspect the pump but took notes, photos of the installation and then said the incorrect installation had damaged the seals on the pump which was not the case.