Combi Boiler problem

[Elliot]

I have a Puma 80, its about 6 yrs old. It got a new PCB 6 months ago because pilot light was going out all the time so it was fixed with that.

Now the pilot light is going out again, but this time there is no banging of pipes when pilot light goes off like before. like before it goes out when HW is used.
The boiler sounds much different to last time it does not sound the boiler is boiling dry it just sounds normal with pump going.

Can any one give me any idea's on what this problem is this time surely not the PCB again, well it was apparently a relay sticking on boiling water dry so over heating. Could it be the HW sensor switch sticking.

Please Please help!!

 

[ChrisR]

Yes it could, but if that was it your pipes would get hot with the heating off, and the boiler/rads would get very hot til it switched off. Do a search - you can usually see if the dhw flow sensor is sticking, through the hole in the hexagonal brass bit where the spring is..

Could be a faulty dhw temp sensor.