No heat from shower

[jonnyg2k6]

I am installing a shower at present and have done some tests and the shower will not get warm until the thermostat is as hot as possible.

It is a thermostatic mixer shower, mains pressure cold and hot from the hot water tank.

Could the pressure be too high on the cold side preventing hot from coming through? If so whats the best solution for this??

 

[seco services]

what shower mixer is it ?
mixers run better on equal pressures.
i'd take the cold from the stored water same as the hot.

 

[jonnyg2k6]

It's a triton antares mixer shower.....

 

[jonnyg2k6]

OK I am going to run new feed from cold water tank so I can get equal pressures on hot and cold. I have two questions.....

1. Can I use the large cold water tank that is used to supply central heating cylinder?

2. The pipe running to the shower is currently 15mm (on mains pressure at the mo), I am unable to change it. Should I run 22mm from the tank down to a reducer or will 15mm from the cold water tank down to shower do the job?

Thanks!!