It's a bit tricky to describe without a picture, but I found one close enough on the web...
So, referring to the illustration at:
http://www.gasman.fsbusiness.co.uk/system_basics.htm
I have a system just like the drawing, except there's an extra pipe from the output of the pump, before the motorized valve, (at the the tail of the red arrow below #4 in the drawing) across to the cold water outflow from the immersion heater coil (the tail of the blue arrow below #6 in the drawing.)
The extra pipe's 15mm diameter (the rest of them are 22mm) and it has a stop-cock on it, which is currently wide open.
Any idea what this pipe is for?
So, referring to the illustration at:
http://www.gasman.fsbusiness.co.uk/system_basics.htm
I have a system just like the drawing, except there's an extra pipe from the output of the pump, before the motorized valve, (at the the tail of the red arrow below #4 in the drawing) across to the cold water outflow from the immersion heater coil (the tail of the blue arrow below #6 in the drawing.)
The extra pipe's 15mm diameter (the rest of them are 22mm) and it has a stop-cock on it, which is currently wide open.
Any idea what this pipe is for?