I have this http://cifial.co.uk/black-780th/ which is now 3 years old. Last Thursday it stopped working and tripped the circuit board. Plumber installed a new like-for-like pump (Salamander CT50+XTRA) and got the shower working again. On Saturday morning it failed to work. I left the small head running and tried different temperatures - eventually it started working. Today (Sunday) same thing has happened again. Grateful for any suggestions on what might be causing the problem.