How to Top up Vallaint Turbo Boiler With Low Pressure Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Roxkolnikov]

Amateur hour over here. I've topped up boilers with low pressure before, but the configuration of this one is new to me; not sure if I can identify the filling loop or whether or not that black lug is a filling valve. The plastic grill in the photo doesn't come off. All thoughts wildly appreciated.

[Roxkolnikov]

Ok, moment of triumph when after searching around the forums I identified the black lug in the picture as a filling key, albeit one that had come loose from the valve. Stripped the pointless key-head off and used a screwdriver to open the loop: boiler repressurised nicely to about 1.2 bar. Declared to partner that I was a gifted plumber. She turned on the hot tap. Then watched in horror as the boiler temperature spiralled north of 100 degrees and the pressure hit 3 bar at a pace. Turned off boiler, it depressurised angrily back to 0 bar. Repeated this exact process an hour later. Moment of triumph ruined. Partner no longer believes my claims that I'm a gifted plumber. Any ideas?