Suprima 40 Tripped, no longer fire up with HW, no response with CH

[hjlp]

My boilers seems to have lots of problem this upcoming winter! It is a Suprima 40 wall mounted gas boilers with latest version PCB(5111606) fitted?

The initial problem is CH won't come on or( have any response) after you switch it on. HW
was working perfectly all right(click, fan, fire up....) before last night. So the only way I can get CH is turning HW at the same time. After all bleeding and try to get air from systems(something related to upstair bath tap), CH are back working normally which lasted in the past few weeks.

But it is very fragile! I had bath last night and could hearing some vibration through pipes. Afterwards the CH could not work, had no response when you switched on. So I had to turned the HW first again to try to get CH working.
However this time, Boiler had been tripped, RCD been tripped, so all sockects had no power supplies...... After I put RCD back, boiler been power on, but it could no longer be fired by swithing HW seperately, you can see the spark , but just can't be fired up. System will be locked after three attemps. LED displayed falsh red which according menu "ignition failure". If I switched CH , again, no response at all..........

I got feeling, I had blown something, any suggestion? Many thanks!

 

[hjlp]

Boiler just been checked by someone. Everything looks as normal apart from no flame and won't be fired up. So he suggested to replace the gas valet first to get HW back working.

Central heating definitely been airlocked. As it had no reponse when you switched on. He also checked the pump upstair. It works fine but don't sound very healthy....(air trapped in).

I am convinced that there is definitly a problem about gas valet. But still not sure should I replace gas valet. I thought there's still a chance some relay or fuse been blown on PCB which will affect control of gas valet. Anyone had similar boilter been tripped before?