Riello G5X Burner

[Johntheo5]

My nearly 20 year old burner has decided to act up, (first time, ever), it fires up fine and runs no problem until later in the day when it develops this very short cycling, the flame seems to go out, (NO Lockout) fan continues to run and it refires again about 5/6 secs later, runs for another maybe 20 secs or so and repeats, if I remove the door it runs perfectly, its just a simple heatpac container with louvers on the door which are perfectly clear/clean so no air obstruction, If I hold my hand partly over the burner air intake you can hear the fan changing tone but the burner keeps firing as normal, there is no snorkel on this burner. The fault appears to be heat related because as soon as I remove the door then the short cycling stops, perhaps fuel oil solenoid breaking down?, unfortunately heading off for 10 days or so, so no time to troubleshoot. I think I noticed this maybe once or twice over the past few years but only for a very short period.

Will renew the door gasket when I return and the burner flange to boiler gasket which I have never removed/renewed, I clean out the baffles and renew the door gasket Bi yearly.

 

[Hairymelon]

Possibly a flue leak filling the case with co2. Fresh air lets it run ok with door propped open.

 

[Johntheo5]

All these burners (RielloG5X) have no gasket/seal between the burner body, (metal to metal bevelled seating), and the flange (to boiler), there's just one fitted stud where you push the burner onto, then one washer and one nut, I've never seen any problems with this arrangement, will post back when I return/investigate.

 

[oilhead]

There is a flange gasket that may have degraded over time. More often though the leak is from the access panel or flue connections. With an analyser, the source of the leak is soon identified.

 

[Johntheo5]

It's no wonder I had to leave the door ajar!!, this gasket has never been removed as I just pull the burner out after removing the one nut&washer, just wonder why the burner never locks out under these conditions, presume there is still some small flame that the photo cell picks up for the 5 or 6 secs that its apparently not firing. There is a 5 sec delay on start up, after the 12 sec prepurge, but the burner should then lock out instantly on any subsequent (real) loss of flame?.