hi smirnoff ! if you have a pump then chances are you have a valve either a 3 port (mid position) or 2 zone valves (2 ports) all this stuff is normally located near the pump and normally in the cylinder cuboard you should see a small box with 3 pipes going into it and a wire (3 port) or 2 small boxes with 2 pipes each and a wire (2 ports) if you have a 3 port then this simply switches the water from the boiler to either heating or hot water and is known as a Y plan but if you have 2 2 port valves then this simply means there are 2 seperate valves 1 for hot water and 1 for heating and this is known as a S plan either way these valves are prone to going and are replaceable with a little mechanical expierience and a few tools, just remember to drain water out first ! and to copy the colours of the wiring (after isolating from mains of course) i would always recomend honeywell valves as these are easy to install and far superior to cheaper DIY store types...hope this helps.....mark
mark the boiler man, November 2008
