S
sully
Hello forum, my first post.
I'm sure you get this all the time, but to come clean I am not Gas safe, I am not a plumber. But I am a mechanic and computer engineer of 32 years experience.
Not expecting that statement to get me any favours! just saying.
Recently my aging 28Si had burner lockout. Solid failure, not intermittent.
I Followed the maintenance MAPS in the book, which (after a bit of basic checking) asked me to test the resistance across the gas valve safety solenoids ( 2 of) which both checked OK, so it said to replace the main PCB. Which I did, (£117) with no joy. So then I got a bit deeper, pulled out the gas valve checked that all three ( 2 safety and one regulator) solenoids were operating OK which they were. Checked all other stuff, pressure switches, etc etc. all working OK.
All of the testing pointed at flame rectification not working, but impossible to see RH side of burner, or to check for proper cross-lighting without covers on.
Testing flame sensor circuit was also difficult (covers got in the way) , and proved inconclusive, even when measured with a DVM in series on AC Milivolt setting, but by gut feel was the flame sensor was not seeing proper cross lighting.
Burner always lit through viewing glass on LH side, but then went out after a few seconds, re-tried several times and eventually would result in burner lockout.
After much faffing, I noticed the RH side of burner was cool after the re-try process, and in a last ditch attempt I swapped the cross lighting strips with a spare burner I had here. (boiler was converted from Natural GAs to LPG on installation, so I had the complete spare NG burner here) with the new CL strips it all works fine! The used LPG strips were dirty, and a bit brown, but nothing too bad. The new ones were obviously new and bright.
Q - what is it that the cross lighting burner strips do , that being slightly burnt and tarnished would result in the burner failing to cross light!?
I appreciate fully I should not be messing (not Gas safe), I have a call out with Worcester to come on Monday (bank Holiday) but in the meantime I would be keen to know if I have made a proper fix, or if it might be just masking another problem.
I should say the boiler is 2002, so 11 years old now!
Thanks in advance, Sean
I'm sure you get this all the time, but to come clean I am not Gas safe, I am not a plumber. But I am a mechanic and computer engineer of 32 years experience.
Not expecting that statement to get me any favours! just saying.
Recently my aging 28Si had burner lockout. Solid failure, not intermittent.
I Followed the maintenance MAPS in the book, which (after a bit of basic checking) asked me to test the resistance across the gas valve safety solenoids ( 2 of) which both checked OK, so it said to replace the main PCB. Which I did, (£117) with no joy. So then I got a bit deeper, pulled out the gas valve checked that all three ( 2 safety and one regulator) solenoids were operating OK which they were. Checked all other stuff, pressure switches, etc etc. all working OK.
All of the testing pointed at flame rectification not working, but impossible to see RH side of burner, or to check for proper cross-lighting without covers on.
Testing flame sensor circuit was also difficult (covers got in the way) , and proved inconclusive, even when measured with a DVM in series on AC Milivolt setting, but by gut feel was the flame sensor was not seeing proper cross lighting.
Burner always lit through viewing glass on LH side, but then went out after a few seconds, re-tried several times and eventually would result in burner lockout.
After much faffing, I noticed the RH side of burner was cool after the re-try process, and in a last ditch attempt I swapped the cross lighting strips with a spare burner I had here. (boiler was converted from Natural GAs to LPG on installation, so I had the complete spare NG burner here) with the new CL strips it all works fine! The used LPG strips were dirty, and a bit brown, but nothing too bad. The new ones were obviously new and bright.
Q - what is it that the cross lighting burner strips do , that being slightly burnt and tarnished would result in the burner failing to cross light!?
I appreciate fully I should not be messing (not Gas safe), I have a call out with Worcester to come on Monday (bank Holiday) but in the meantime I would be keen to know if I have made a proper fix, or if it might be just masking another problem.
I should say the boiler is 2002, so 11 years old now!
Thanks in advance, Sean
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