Euro Combi sx20 PCB

[niannorth]

 

[ChrisR]

First try cleaning all the connections, they're notorious. Something like typist's rubber is good.
First find your typist!

Last time I used contact cleaning fluid and kitchen roll type stuff wrapped round a jewellers screwdriver - you could use a matchstick.

 

[niannorth]

 

[niannorth]

 

[ChrisR]

Hold on, what's the failure sequence exactly?
It's alight, burning happily, then what?

 

[niannorth]

 

[DP]

What are you goint to do if it is NOT the PCB. Another case of "I think it is the PCB. I will change it". Why not prove it is the PCB before you embark on that exercise.

Do you know what the boiler is attempting when the spark appears at the burner. If you do, you are on your way to finding the defect. If you don't, stop messing about and call someone who knows how the boiler works.

 

[niannorth]

 

[bengasman]

I changed the flame detector, checked the cable with a meter, checked the resistance of the flame detector both cold and hot and it was as it should be.

Don’t know this model by heart, but all the flame sensors I know measure just about zip including the cable. What values did you measure and how?
Bit of a wild guess, but the tip of the sensor going full blast would possibly not be too far off 1000C. could be a bit painful measuring that.
I have a feeling you have been measuring the wrong sensor

 

[Agile]

checked the resistance of the flame detector both cold and hot and it was as it should be.

I thought the writers of the Ariston service manual may understand how the boiler works

What exactly was the resistance of the flame detector? And what should it be?

Dont expect the writers to have ever mended a boiler! For a start they are not CORGI registered!

Tony

 

[niannorth]

 

[bengasman]

but was it still .5ua , i take it that stands for micro amp, when it was locking out?

 

[niannorth]

 

[Agile]

All I can say is that you dont seem to understand how the flame sensor operates or to have done any meaningful measurements!

For my amusement what resistance value have you measured and between what have you measured it?

Tony

 

[niannorth]