In article
KW_UK wrote:
Hi,

managed to find all of this, was hidden away and had no lever!

got the pressure up, bled the radiators, the pressure dropped again so
topped it up to 1.0 bar.

now the boiler turns on, then goes off after approximately 30 seconds.

can't think why, any ideas?

Airlock? Either in the boiler or at the pump. Just guessing.