Heat Exchanger failed ?

alanobrien

Long story short, i am chasing down the source of a leak in our system boiler a Vaillant 622/2E (circa 6 years old)

Its definitely the boiler as pressure falls when its isolated.

It had a new expansion vessel and PRV 2 weeks ago by a GSR
The heat exchanger cover plate gasket and condensate gasket were also replaced at that time. The engineer looked at the heat exchanger after cleaning it up in situ and said it was a bit distorted but ok.

All was ok for a day then the pressure drop rate increased.
No visible signs of leakage elsewhere inside the boiler.
The pressure drops completely over a 12 hour period when the boiler is in use and by at least 0.5 bar when not in use.

I noticed today that the condensate pipe was constantly dripping (boiler off for last 24 hours) and considered that the heat exchanger may be perforated and leaking across into the condensate chamber.

Anyone come across this ?

Any other thoughts gratefully received.

alanobrien

Just for the record i managed to get hold of a vaillant engineer and they confirmed the diagnosis, the heat exchanger has perforated - they are coming to replace it on Thursday.

southcoastrgi

A 6 yr old Vaillant with a knackered hex OMG aren't they suppost to be the best thing since sliced bread :cool:

gas4you

Fairly common problem I'm afraid, but something your RGI should have checked, I would have thought?

alanobrien

I would have thought a stainless hex would last longer but hey ho......
He did check it in place, and thought it looked ok. He gave it a bit of a clean up in situ and i suspect that may have dislodged some detritus and actually made it worse. such is life......