Help! Trevi shower problem!

[Chrisalis]

Recently moved into North Walsham area. (Norfolk) The house has a Trevi shower that isn’t working properly. The hot is overpowered by the cold? Two plumbers so far have had a look but no success. Need a plumber with experience of these showers as they obviously have very specific issues that make them difficult to fix?

 

[exedon2]

Picture of shower would be useful
Its not a trevi boost shower by any chance?

 

[Chrisalis]

Picture of shower would be useful
Its not a trevi boost shower by any chance?

Yes we think it is a Trevi Boost shower. Don't know if photo will help. There is nothing on the unit to help identify it.

 

[exedon2]

The trevi boost is tank feed hot and mains cold it works on a venturi using the higher pressure cold to 'accelerate ' the hot. You will need your hot water to be at at least 60 c to have a hope of a warm shower.
Should say I've taken a few out and replaced them with something more conventional.

 

[Ben-gee]

Venturi shower, where mains cold draws the gravity hot into the valve.
These can work pretty well, but it sounds as if you have a faulty non-return valve on the hot side.