Can you confirm that the cold water feed to the boiler is currently off?
Yes I turned both valves back to the off position otherwise the boiler pressure would continue to rise.
There is only one that makes the water go through the boiler to feed the hot taps.
The other is just to fill the heating.
Have you tried turning one on only?
Can you attach a photo?
There is the valve from the mains that is only used to fill the boiler that needs to be turned with a screw driver. There is also a valve with a big red tap that is also usually turned off, when both taps are on the boiler pressure increases. If I leave the red tap on (second in the line of flow) but turn off the mains valve, the hot water works for a few seconds but the pressure in the boiler plummets then the whole system turns off. By having both taps turned off at least the heating works. If both taps are left on the pressure just keeps increasing, if the first valve is left on but the red valve closed then nothing happens.
Yay, I have hot water and heating thank you. I thought I had tried all the valve combinations obviously not. Will get the valve and loop replaced. Thank you again. Joy