vaillant 831 combi

[thomas donovan]

have instlled above boiler, has been working fine now there is an intermittent tick which seems to be coming from the heat exchanger when heating starts to warm up and then once its cooling down surely if this is due to expansion/contraction it would have started from day 1 any input would be appreciated

 

[diesel_ltd]

i would say its most likely just expansion/contraction, possible air in the heat exchanger hard to say with out hearing it

 

[thomas donovan]

yeah i thought that may be a possibilty but surely the aav should get all air out,seeing as thats what its purpose is

 

[thomas donovan]

ok, i isolated the flow on the boiler opened the prv and filled system so as to flush any air out of the heat exchanger coil. still got this effin tick sound, almost sounds like a springy click. someone click their fingers and make it disappear for me please. failing that any suggestions would suffice

 

[CHJoys]

Have a read of this link

http://www.atmos.uk.com/core_files/document(124).pdf

Is a link to atmos document but sounds like Vaillant could have the same issue as what you have explained fits what they say in the document - apply ceramic grease on the contact surface that surrounds each screw hole of the front plate, this will stop the jerky expansion contraction between the heat exchanger and the front plate after this replace the old silicone sealant ring with a new one for safety before tightening the screws back on. The possible reason its happening recently rather than from the start maybe that initially the expansion contraction of the plate had a smooth motion with the heat exchanger but with continous expansion contraction has turned it jerky?, not sure but worth a try, you can pick up the ceramic grease for less than a tenner and the silicone sealant ring would be very cheap to replace, just do all safety checks in the end for leaks etc and hopefully this would sort it out, good luck.

 

[thomas donovan]

thanks chjoys i think thats exactly what i've been looking for, will try it when i go back. AGAIN