Hi Saunier Duval F28.
Pressure dropped so Red Light and stopped.
Checked for leaks and refilled with blue valve.
Stopped refill at 1.0bar.
System came on. Next time I looked Pressure up to 1.9bar. Got worried when it got to 2.2 bar so bled radiator. Pressure came back down to 1.2. Next morning down to 0.3bar.
If relevant Radiators all red hot but hot water never gets that hot. Grateful for any advice not advising using large hammer and buy better boiler.
check the pipe coming off the pressure vessel at the back of the boiler as this was blocked and had trhe same problem had to drain system down to clean the pipe is at the bottom at ythe back