Worcester Greenstar 40CDI combi

[BoooooM]

Hi guys

Just looking for a little assistance on this as its puzzled me.

Got called out to a 40 CDI today that wasnt firing. Upon enquiring, customer advised that many parts had previously been replaced... namely; Fan, gas valve, primary heat exchanger... All by worcester bosch engineers. The boiler had been working fine for about 6 months but now doesnt seem to fire.

Strangely though i found that the boiler ONLY fires and remains lit when i block the air intake. Assumption here is that the air gas mixture is all wrong so removed fan to check diaghragm in airway and all seems fine. Diaghragm is intact and in good nick checked all flue seals etc but cant see why the boiler will only fire up when i put my hand accross the air intake.

My initial thoughts were to complete a flue analysis but im not sure how helpful thats going to be if i have to interfere with the air intake in order to do keep the boiler fired up... I can say however that the CO levels were through the roof though. Flue analyser went nuts.

Any thoughts
Many thanks in advance

Ps gas inlet pressure checked and all fine

 

[ianmcd]

Sorry to give you a reply that is not helpfull but you have a combustion problem and as such the site rules quite rightfully prevent us from answering on an open forum, register for the Combustion Chamber on here and ask the same question and you will get all the help you need

Cheers

Ian

 

[BoooooM]

Ok Thanks

Registration Pending

 

[ianmcd]

I have no doubt that you are a genuine RGI but if we give an answer on an open forum unskilled may read it and attempt to repair if they feel they have a similar fault, that is one of the reasons for the rules, keep your analyser away from it though until it is stable or you will flood the CO cell quite costly to remedy, its not a hard repair by the way

 

[BoooooM]

Yes i can understand the implications of such advice on open forum. Hope to hear from you on the CC once i can log on. Hope it doesn't take too long as i'm due to go back to the job tomorrow pm.