combi pressure rising!!!

[jules85a]

I have a combi boiler that the pressure dropped right down on and switched itself off, so i used the two taps underneath and re-pressurized it.
eversince i have done that the pressure keeps rising and going into the red. I have on numerous occasions now reduced the pressure by draining down a rad only for it to come back up again.
I have checked both the valves and they both seem to be prop turned off no problem.
So any ideas would be great. Cheers Jules

 

[BingoBongo]

check faq`s for represurising expansion vessel

also make sure the cold main tap isnt passing and constantly filling the system.

if the pressure rise is when heating is on -exp ves

still rising when boiler off-tap passing