Baxi Eco 80 Fault

My Eco 80 is once again giving me trouble (curse the previous owner who had it fitted), it lights, waits 6 or 7 seconds then goes out again, waits another 30 seconds or so and tries again, same thing, and so on to infinity I assume. Following the fault finding guide in the manual I checked the flame sensing electrodes, they seem fine, but I cleaned the tarnish off just in case, checked the sensor current with a multimeter and got 4-5uA and the manual says approximately 1uA should be present so I assume this is ok. The manual then says change PCB, so at enormous expense I have done that, no difference. I'm at a bit of loss as to what to do next, my only thoughts are the modulating gas valve, does it light on a low pressure, and then once its happy it has a flame close that valve and open another to switch up to a high pressure? Any other possibilities? I have checked the resistance of the temperature sensor and it is approximately the 11k the manual dictates.

Reply to
Cod Roe
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In message , Cod Roe writes

Assuming that you are getting a spark and GV operating, i.e. that there is a flame to sense ...

Reasons for flame sensing failure are

1) pcb - unlikely from what you have said above 2) break in the wire from the electrode to the pcb (are you really getting 5uA ?) the only way I know of reliably testing the lead is to give it a tug at both ends to see if the wire is attached to the connector 3) Electrode not in the flame 4) bad earthing 5) Live and neutral transposed (unlikely unless you have recently done some electrics)
Reply to
geoff

Yes, there is a flame to sense.

I'm not paying for another one to test that further!

I have checked the resistance from tip to spade with a multimeter and all is fine.

The thing is rigidly fixed, though slightly off the flame, and the boiler just failed in service without anyone having been near it for months, so I doubt it had moved. Anyway, I measure a current once it lights.

The earthing hasn't changed, but could you elaborate? Water and gas primary bonded to the boards riser, and the ring main earth is fully functional.

Had that some months back, when the plumber had kindly put both ends the wrong way round, how anyone can do blue to brown and brown to blue without feeling guilty I don't know.

I checked the gas valve with a manometer and it seems to be delivering full pressure.

About to give up on this one, and maybe get a Worcester Bosch Greenstar

30Si to replace it, anyone got any comments or suggestions for a better machine?
Reply to
Cod Roe

I can test Eco 80 pcbs

it's what I do

You didn't read what I typed, did you ?

Whatever, if the electrode is not in the flame, it won't flame sense

flame sensing is referenced to earth

if there is a problem with the earthing anywhere within the boiler, this could cause problems with flame sensing (including to the pcb)

So you have let a clueless d*****ad near your boiler - best check out the wiring again then, just to make sure

and ?

like measuring the temp sensor - a red herring

I have listed the possible reasons for a lack of flame sensing, go and work through them properly. Start at the beginning, don't make assumptions and don't take anything for granted - it's easy to overlook something that you think must be OK

If you want the pcb checked out, I can do it

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but I think your problem lies elsewhere

Reply to
geoff

Bookmarked (Don't let UKRM know you do this or you'll be inundated with work from WC....LOL!)

Reply to
RW

In message , RW writes

I gave up with WC last winter ...

Reply to
geoff

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