Baxi 105e spark problem

[Racing Green Bo]

Hi all hope you can help.

My baxi 105e will happily run then stop with flame failure light. The actual problem is that the igniter is not working. I have discovered that when it trips out and after I have reset it and allowed it to run through its start up sequence it will still not produce a spark however, if I put my voltmeter probes across terminals 3 and 5 while it is going through the ignition sequence, it will guaranteed spark away and the boiler will happily run again for a bit. I realised this when going through the troubleshooting flow chart trying to work out if there was a voltage being sent to the igniter. This also works if I put the probes on the line and neutral of the ingniter unit.

Should mention have changed the PCB for a new one. Same problem which can be rectified with the same solution. For some reason bridging out the terminals with the voltmeter allows the igniter to spark. Ok for me to do to get it going again not ideal for the wife!

Cheers in advance

 

[marcusone]

Hi
If it sounds like it is generating a spark then the next check is electrode lead and spark electrode. Check the spark is not shorting out somewhere and that the electrode to burner gap is correct. If you have a spark at the electrode the next stage in the ignition sequence is low gas on the burner followed by flame rectification by the sensing electrode. Then full gas.

Cheers.

Sent from my HTC One X using Tapatalk 2

 

[telectrix]

sounds more likely that the control unit is not sending a spark signal, which is overridden by the test meter.

 

[rsp84]

Is it a combi? will it work on the central heating but not the hot water? if so, had similar issue with the overheat stat for hot water.

 

[Racing Green Bo]

Yeah its a combi and it does it on both HW and CH. I know the start up sequence noises by heart now and even if I don't get a spark for the first two seconds when it should be sparking then hit terminals 3 and 5 with my probes instant spark in the window and away it goes.
I'm sure these things have a life of their own since posting it has run all day without flame failure. Swear that things laughing at me!

 

[rsp84]

Boiler fault finding is tricky unless youve got parts to throw at it. Have you tried asking the plumbing forum?
It sounds like the overheat stats as they get scaled up. If you turn the water off to the boiler, you can get a spanner and unwind the stats (only water in the boiler pipework comes out, which is very little), you can use a wire wool scower to get the scale off and place them back in. That way you havent wasted money on parts and it will show if its been messing with the stat. Another clue to if it is this would be the hot water temperture wont be as hot as normal.

 

[MarkieSparkie]

Assuming you are talking about pins 3&5 of connector A1 which go directly to the spark generator and you can hear the fan running.
First, clean and tighten the terminals to the spark generator. Second, clean and re-gap (3-4mm) the spark electrode(s). Third, clean and re-tighten any connections from the spark generator to the spark electrode(s). Fourth, if these fail to solve the problem replace the spark generator.

If however, you are talking about pins 3&5 of connector A2 and the fan starts running and the ignition fires when you 'short' these pins. Then suspect poor connection(s) to the air pressure switch (clean and re-tighten) or a faulty air pressure switch (replace air pressure switch).

 

[Johnuk]

do you hear the fan kick in????

 

[tamz]

If you'd gone to a decent heating guy it would have been fixed for less than the cost of a board.
Sometimes diy repairs are false economy (and dangerous).

 

[CES Heating]

:iagree: Get a GSR engineer in. Im sure you guys wouldn't encourage DIY electrics so why DIY gas work?

 

[Racing Green Bo]

Yeah but when your plumber has tried all the components baxi has told him to change and finally tell you to change the PCB (because I guess they have run out of guesses) what do you do but go out and buy one because afterall hw and ch would be useful. Thanks though for adding your assumption insult to my expensive injury.

 

[gas man]

get a gas safe registered engineer in who knows the 105 throwing parts at a boiler with no understanding of how components work is a big spend and at best a guess at whats wrong

 

[gas man]

Yeah but when your plumber has tried all the components baxi has told him to change and finally tell you to change the PCB (because I guess they have run out of guesses) what do you do but go out and buy one because afterall hw and ch would be useful. Thanks though for adding your assumption insult to my expensive injury.

we are trying to help you fella,you are on here looking for help being given good advice but still prepared to maybe kill someone in the process of finding the fault

 

[Racing Green Bo]

Totally agree please be assured my gas safe plumber won't kill anyone, but seeing as i am in the electrical industry myself you must understand that seeing as its my boiler that's not working I am going to discuss an electrical problem with like minded people in case anyone has come up against this problem before which may help my guy sort the problem. It's peoples assumptions that i am diy'ing (or my plumbers not decent) on my boiler that gets me cross. I don't do gas and never will its like electricity best left for those who know and are qualified for what they are doing. I appreciate and understand your intentions are all good.

 

[Croppie]

Even so.the minute you start opening up a boiler you are entering a realm you cannot prove your competency in unless you're a gsr!

 

[peteheat]

Electricians have laws, rules and regulations that prevent those considered incompetent by virtue of the fact that they have not been trained and hold certificates, well so do GSR's.

Under (Irish) gas safety regs you can be jailed for working on your own boiler.

The big difference is an electrical fault as blatant as bare wires on display will not harm anyone until they touch them, with gas a small leak can blow up a house, factory, or apartment block, in one recent case in Ireland gas blew up a house that didn't even have a gas supply, the problem was in a house two doors away.

If your GSR plumber was in the service business he would have solved the problem without contacting the manufacturer, many of the GSR's who posted have already diagnosed the problem and have never even seen your boiler.

At least have the common courtesy to respect other competent specialists who express their point of view instead of trying to defend your actions with an argument that your own trade would deem unacceptable if they were discussing an electrical problem on an open forum.

 

[Racing Green Bo]

Very well put. I totally agree am eating humble pie and do wish to give you gsr's the common courtesy you deserve so i whole heartedly apologise and will call a baxi service engineer. Cheers to all who have posted.