combi boiler pressure dropped to 0

[Mrfenfen]

Hello I have an old Aristone A23 MFFI. Yesterday the pressure gauge was at 0 Bar yet the heating was working on timer. I shut it down I didnt want to fill it up again in case it has leak under the floor as no visible signs of leak anywhere from any radiators or pipework. I then filled it up to one bar turned it back on and it wont come on, I checked the internal fuse on the PCB its fine so I have ordered a replacement board. My question is the pressure has stayed at 1 bar for a day so hopefully not a leak what else could have caused the pressure drop to 0
Thanks

 

[dcawkwell]

It possible that you have a defective expansion vessel and the boiler dumped the water from the pressure relief pipe outside.

When you say it isn't coming on are there any lights on?

I believe the pressure sensor on these can get gunged up.
So push the pressure up to 2 bar and leave it for a few hours then try the boiler again.
You can release the pressure by bleeding a radiator.

Awful boiler to work on. Very badly thought out.

 

[Mrfenfen]

Thanks dcawkwell,

The boiler wont turn on at all no lights I have checked the fuse in the power spur and the glass 3amp fuse on the PCB both fine. I have ordered a replacement board only £85. I had similar issue before when pressure dropped to 0 I filled it back to 1.5 went to be in the morning it was at 3 so I have to bled from rad to get back to one. Maybe pressure sensor playing up as has history. I might get someone in to check the expansion vessel. Its a horrible boiler I want to get a worcester in but trying to keep this old one going so need to weigh up pressure sensor and expansion vessel costs against £1k plus install for replacement