Hi,

I have a Vaillant eco TEC 831 boiler. It has needed topping up several times in the 3 years since it was fitted. This weekend, it needed doing again. While filling it, I noticed the carpet was damp under the boiler. Then I noticed that it was dripping from the bottom almost as fast as it was going in. I can get the boiler to fire up and run for a couple of hours until the pressure drops enough to knock the boiler off.
Can anyone tell me what could have gone wrong as my plumber is a bit suspect and I have already caught him out trying to fleece me once. This has given me a deep mistrust of all plumbers. Forewarned is fore-armed as they say.

**** I do not intend attempting a repair myself, I just want some idea of the problem.

Moose, January 2014

Thanks for the replies guys.
Had a major leak today over a gallon in 1 hour.
Took the front off and pulled control panel forward to find a black rubber hose on the left leaking from top and bottom.
I have now called a plumber in.
At least I now have an idea of what is wrong.

Moose, January 2014

All s code means to be investigated 89 flow sensor need check not bloked ,s22pump running make sure not dry run because of water loss s7 mean pump over run sense blockage boiler need good clean up ,all S. Code is warning signs it not faulty

ltd, January 2014

Not opened casing, just control cover.
The leaking water all seems to be coming from the left hand side if that helps.
Error codes shown include

s.98
s.22
s.07

Hope this sheds more light on things.

Moose, January 2014

Did you notice any sign of water inside boiler,in older 831 flow and return connected with rubber hose pipes they have problem and leak ,now they change to all Cooper ,if any leak under boiler is quite noticeable there are four connection ,make sure all tight

ltd, January 2014