Riello rdb 3 going for 2 hours then cutting out

[Inverness]

Hi guys, riello burner is cutting out after it’s been running for 2 hours solid. Replaced new photo cell, nozzle, capacitor, I’m trying to fit a new solenoid tomorrow. Any ideas if this fails?
Thanks

 

[pete40]

Was going to say Solenoid but also thermostat issue?

 

[SimonG]

What's the combustion like?

Checked fuel supply, filters.

 

[SJB060685]

Riello solenoids are usually pretty bomb proof so I doubt it's that, although I could be wrong. Have you been at the burner at point of lockout and has it gone through the motions to start again?

 

[Inverness]

I have been there when its up to temperture itslockouts out. It’s a new rdb3 burner clean looking. Motor and fan sound normal. Any suggestions? Electrodes are arking? Could it be oil supply maybe water ? Or new oil pump?

 

[SJB060685]

So flame fails and you hear it go through restart cycle but no flame established?

 

[MikeJhn]

Sounds like water in the oil to me, do you have a glass bowl filter to look at? or just drain off a bit into a glass container, let it settle and then look at the bottom to see how much is water.