Bristan Mixer Shower Keeps Going Cold

[Bazza4465]

I have a Bristan mixer shower that keeps going cold, it goes cold for a minute or so and then comes back hot before going cold again. I have replaced the cartridge in the shower and also replaced the shower hose, there was a slight improvement for a week or so but it is now back to what it was like before. I have the same model shower over the bath and there are no problems with that so I assume the problem is with the shower itself. Any advice to help sort this out would be appreciated.
Thanks
Bazza4465

 

[ShaunCorbs]

Hot and cold pipes in the right way ?

Always done it or just started ?

 

[king of pipes]

Also what boiler do you have is it a combi by any chance ? Cheers kop

 

[Bazza4465]

Hot and cold pipes in the right way ?

Always done it or just started ?

 

[Bazza4465]

This has only started over the last few months and slowly got worse. The shower is a number of years old and worked okay before, nothing done to the pipework so the hot and cold are in the right way round.

 

[Bazza4465]

Also what boiler do you have is it a combi by any chance ? Cheers kop

 

[Bazza4465]

The boiler is a combi, it is a Worcester CDI.

 

[ShaunCorbs]

All other taps ok ?

 

[steadyon]

If its has them, check the non-return valves and filters in both inlets.

 

[Bazza4465]

I have the same shower over the bath in the same room and there are no problems with that.
How do I get to the non-return valves and filters to check them, do I have to take the cartridge out?

Thanks for your responses.

 

[steadyon]

If its a bar mixer, the filters will most likely be in the two inlets where the shower is attached to the wall, and probably no non-return valves.
If it's a concealed shower, could be anywhere.
Need to know the type and model.

 

[king of pipes]

Just a thought watch what the boiler does when the shower is running if you have other showers that work ok there must be a restriction somewhere

 

[Bazza4465]

If its a bar mixer, the filters will most likely be in the two inlets where the shower is attached to the wall, and probably no non-return valves.
If it's a concealed shower, could be anywhere.
Need to know the type and model.

I only know that it is a Bristan shower. Attached is a photo of the shower and one with just the cartridge showing, is this of any help to show me where the non-return valve and filter are.
Thanks

 

[Bazza4465]

If its a bar mixer, the filters will most likely be in the two inlets where the shower is attached to the wall, and probably no non-return valves.
If it's a concealed shower, could be anywhere.
Need to know the type and model.

Sorry about the last post with multiple attachments, I didn't think they were being attached and tried multiple times and posted it before realising.

 

[Bazza4465]

Just a thought watch what the boiler does when the shower is running if you have other showers that work ok there must be a restriction somewhere

King of Pipes - What should I watch for on the boiler when the shower is running.

Thanks