Unica 28 HE

[bantamgas]

Right Folks
Was asked to look at one of these today,I dont know a great deal about them so here goes.
The boiler works ok on dhw and heating but about 2/3 mins after shutting down the whole combustion chamber starts to vibrate and there is a strong smell of gas coming from the boiler.I can't seem to find where it is coming from though.Any ideas please?
Ta.

 

[Barry98]

is it defo gas and not POC

 

[bantamgas]

Definitely gas seems to be (and this is only a guess)coming from where the gas feeds into the fan housing

 

[Barry98]

real stupid of me to suggest this but youd be surprised how many a man its caught out butthe test nipple OUT on the gas vale is tight yes ?

 

[dancinplumba]

is the flue ok ?

 

[bantamgas]

is the flue ok ?

The flue itself is fine.....but,where it exits the wall,the wall has not been fully made up.Bearing in mind the benchmark date of dec 07,I don't believe that this is a contributing factor being as it has run ok since then( to the best of my knowledge)

 

[dancinplumba]

is the ***bustion insulation in proper place ? had this on a remeha once

 

[bantamgas]

is the ***bustion insulation in proper place ? had this on a remeha once

All seems ok.
Because of my lack of knowledge of it,I have passed the job on,I'm just interested as to possible causes.
Thanks for all your answers,and if any more suggestions,keep 'em coming.

 

[dancinplumba]

check flue gasses

 

[leedsgasservice]

Replaced the flue fan on one of these today and noticed I had a strong smell of gas while the boiler was running.
at first I thought a gasket had been trapped or ripped but when I removed the fan, I noticed that in the casting towards the outlet of the fan is a nipple with a hole in. On the original one this is blanked off.
looks like it's either a design fault or the wrong fan but in every other way it's identical.

back to the suppliers tomorrow. One to watch out for.

could of been a bad one.