corgiman said:
I didn't mean my last post to sound so belittling. The help I have received from people on these forums has been top notch... the British Gas man is here right now replacing the actuator with a new one (Grunfoss(?) I am told).
I have asked to keep the old Siemens head. The plastic thread that moves the cog to move the ball one-way-or-the-other have diminished and it was these thread/cog slipping that caused the level to (s)p(r)ing back into original position (hot water only)! You learn something new every day.
He has altered the piping somewhat to fit the new port in? Had to turn off the cold water supply, drain the radiator system, and then cut a small piece of copper piping away. He is now just wiring the electronic actuator back in and then job's done... 150 quid.
