Baxi combi 133 he plus intermittant ignition

[dougal]

HI GUYS

Boiler serviced last week by colleuge. he ordered new burner, electrode assembly with electrode lead. i fiitted these parts the old burner had ripped on outer edge.
since these have been fitted boiler has inheritted intermittant ignition fault. new fabric burner has been replaced like for like, electrode kit on old one was in two parts and new one fitted was one piece. when calling demand fan runs for five seconds, hear clunk but no ignition. fan stops and sequence starts again. doesnt make any difference if cover is on or not. if power is turned off then on at spur the boiler will sometimes work. try it several times it will fire up straight away.
im thinking may be new electrode is faulty as prior to parts been fitted was working o.k or it could be arking on casing.

anyone had this fault before

cheers

 

[Jimbob]

Check the condense trap connection, it would be blocked and arching the ignition to ground. You can disconnect a spade connector to test. You might have already tried this

 

[dougal]

Thanks for your advise. didnt think of that but i know what you mean if trap is blocked one of white wires is damp it can stop boiler from working as safety device. will check trap is clear and that both spade connectors clean and dry.
would this give intermittant fault

 

[Jimbob]

Exactly. Yes iv had it after washing out the traps. Probably wouldn't be intermittent though.

 

[Ermintrude]

Spacing between electrode and burner? £1 between points (4.5mm) is rectification in flame and connections all insulated / clean?

Turn lights off and ignite, spark should be strong between points end and burner. Is burner earthed properly?

 

[dougal]

i will check make sure new burner is earthed properly. should be less than 1 omn.
thanks never thought of that.
going back monday will take another electrode assembley will double check gap

cheers

 

[ambrosia]

hear clunk but no ignition

what do you mean by a clunk noise, do you mean the sparking of the ignition because if its sparking but not lighting i'd be looking at the gas valve, solinoids can be interminant although that wouldnt explain why its started happening after you did the work

why were the electrodes changed

 

[dougal]

problem solved adjusted gap on electrode is now working better, however once cover was put on same fault reoccured, where fan would run for just 5 seconds send 240 vdc to gas valve for only 2 seconds then loose voltage at gas valve and fan, re tries again. did earth test which was 40 omms from boiler chassis to earth at spur, tested earth from sink to spur that was 38 omms. so the fault was with bad earth to spur. electition coming to sort it. BIG THANKS TO ERMINTRUDE for reminding me to test earth

 

[buckley plumb]

these are terrible boiler seen them self destruct and melt the case . as mark about them .

 

[Billy Bob Bob]

these are terrible boiler seen them self destruct and melt the case . as mark about them .

wont work on them there heaps,and yes they do melt very easily normally its the burner that causes it