boiler goes out after a few minutes?

Most boilers have a gauge on the front and has to have the needle set to at least 1.5/ 2.00 on the gauge otherwise it will swith it's self off to save burning the pipes out, underneath the boiler you should see a small copper pipe with a tap at each end turn them both inline with the copper pipe and watch the gauge till it reaches at least 1.5 then turn the taps off, the boiler should then work,
Hope this helps you and others.

Rick.
August 2016

it's not clear which valve you have there are two types a mid position valve where water can go to c/h and h/w at the same time (normally the valve is open for c/h until powered) or a divertor valve where the valve is off unless powered up suggest you remove cover of the wiring centre and trace and test if your not sure how to do this let me know (first check if valve has 5 or 6 cables)

brian
March 2011

thanks i done that the 3 port goes across ok and the water goes where it is supposed to but then the boiler cuts out on heating only and the rads dont get hot, i'll try the pump screw this evening
thanks Mark

Mark
March 2011

turn heating and h/water on make sure boiler fires up then check which pipes are getting hot on the 3 port valve turn cylinder stat down the actuator should then divert water to heating if it doesn't then either (depending what valve it is ) it's the actuator faulty or the internal cogs slipping or the ball in the valve body has snapped off to check if pump is working remove chrome nut in centre and you should be able to see shaft rotating

brian
March 2011