Baxi 105he flame failure Fault.....

[theonefromthesky]

Wondering if you could be of assistance please.

Just been renovating a house after we bought it as a repossesion. After taking some measurements, I wasn't happy with the placement of the boiler, it was too low. So seeing as I needed to replumb, rewire and just about everything else in the house, I promptly removed it from the wall and stored it in a cupboard.

4 months on Im now ready to put it back again 5 inches up the wall with new central heating system to it. SO I heave the damned thing back on the wall, prime up the system and purge of any air etc etc. switch on electric turn knobs to max, turn and hold to reset for a few seconds and let it do its thing.

The on light appears, it clicks a few times, and it ignites. So it runs for a few seconds, and then promptly goes out after 10 seconds. It then restarts the whole sequence twice more, to which Im then greeted with a flashing flame sensor/condensate drain blockage, well the condensate drain isn't connected and theres only an inch of water in the clear trap on the right so Im certain its not that. So I think aha! Must be flame sensor. So I look at the installation manual and discover that the ignitor and the flame sensor are the same part number, so I whip off the cobmustion chamber and swap them round, reassemble and turn back on. Still no joy and runs through the same process. the same can be said for hot water demand, same sequence as above. So I fiddle around with it a bit more and do some tests. In the manual it states the flame current should be 1 micro amp, to which I don't have a multimeter sensitive enough to measure, however I do know that when the boiler is lit I do get aroud 1.5v from the flame sensor so I would imagine thats not the problem. unfortunatly what this does mean is that its potentially the Board, which I would imagine is remarkably expensive.

Unless of course Ive missed something stupid?

Anybody care to shed some light please?

Thanks in advance,

Jody

 

[Baxmax]

What is the low burner pressure reading ?

 

[Baxmax]

Is the polarity correct ?

 

[theonefromthesky]

Havn't the foggyest, I have no specialyst test equipment to measure Im afriad. I forgot to add that during the sequnce from first ignition, you can hear and see the sparking electrode all the time the flame is lit, even when it goes from low to high flame.

Jody

 

[theonefromthesky]

I would bloomin hope so, as by trade I am an electritian. However, I will double check it when I am next over, but Im 99.9% sure that it is!

 

[Baxmax]

AH yes but were you the electrician who wired it up,if yes then you would know the polarity is correct,the symptom does fit the diagnosis.

 

[theonefromthesky]

Its an interesting point and one I didn't consider, I did run the new kitchen ring main but I used the existing flex/plug. Perhaps a quick check of this would be a good place to start. Beyond correct polarity, would I be correct in assuming that its lookign like a new board?

Its a shame but I have no idea if it worked before I took it off the wall, only because I didn;t want to use any of the previous owners shoody work.....

Im suprised that in the manual it doesn;t mention polarity, as most devices arn't specific on AC. It just blindly assumes that people understand colours....

Jody

 

[Baxmax]

Keep us posted......

 

[baxpoti]

Im suprised that in the manual it doesn;t mention polarity, as most devices arn't specific on AC. It just blindly assumes that people understand colours....

Extract from the 105HE fault finding guide which you blindly assumingly read? No. 2 is the clue.

14.0 Fault Finding

Carry out initial fault finding checks

1. Check that gas, water and electrical supplies are available at the boiler. Electrical supply = 230V ~ 50 Hz.

CH water system pressurised to 0.5 bar when the boiler is cold. The preferred minimum gas pressure is 19.5mbar (natural gas), or 36mbar (propane).

2. Carry out electrical system checks, i.e. Ground Continuity, Resistance to Ground, Short Circuit and Polarity with a suitable meter.

NOTE: These checks must be repeated after any servicing or fault finding.

 

[Baxmax]

The lads !