How to Repressurise Vaillant Boiler?

I returned from a weekend away and noticed that the boiler was flashing “0,8 bar”.

I put the heating on and the the “0.8 bar” message has since disappeared but the water level is right on the edge, so it needs topping up.

I’ve looked underneath and below the boiler but I’m still not sure how to repressurise it. Nothing matches what I’ve researched online so I’m hesitant to mess around with pipes when I don’t know what I’m doing.

I’ve attached some photos.

I’ve tried turning the white taps but they didn’t seem to do anything. Am I missing something really obvious?

If anyone could point out what to do, it would be much appreciated.

open one white tap then open the other slowly that will do it up to 1.2 will be fine close both taps

cjg said:

open one white tap then open the other slowly that will do it up to 1.2 will be fine close both taps

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Thanks cjg. Do you normally turn them clockwise or anticlockwise?

Solomon Grundy said:

Thanks cjg. Do you normally turn them clockwise or anticlockwise?

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anticlockwise,