Re pressurising Viessmann boiler

JG54

Hi!
I saw that the pressure went below one on the reader and top up the pressure to 1.2 without turning off the central heating / boiler.

I only found out afterwards that I should have turned off the central heating/ boiler before repressing. 

Have I damaged the boiler now?

Typhoon2000

No the boiler will be fine.

grumbler

I don't think so. All boilers have a pressure relief valve that prevents any possible damage caused by pressure.

Bendy_House

Very very unlikely, so don't worry.
The boiler was 'on', but was it actually running? Even if it was, don't worry.

I imagine the reason it should be done with the boiler off is that you can see the static pressure, and not one affected by a running pump or hot boiler. Also, if you accidentally overfill the boiler, you can sort it (by bleeding a valve) before turning the boiler back on.