hi all ,in need of a bit of help for a sick vaillant 828 turbo plus
fitted about 3 years ago,a brief history>>>boiler fitted but system was
not flushed first(i know) hence never worked properly from word go had
vaillant engineer down diagnosed secondary heat exchanger blocked (full
of black bits)cleaned it got boiler working and recomended a power
flush.system power flushed(plenty of black dirty water)boiler sort of
working better but gradually got worse so brought new heat exchanger
and still the same next fitted diverter valve still no joy whats always
happened is the boiler takes ages to cut in when there is a demand for
hot water, heating works fine, sometimes hot water demand works fine
sometimes 20 mins or so for it to cut in
if any one can steer me in the right direction it would be much
appreceated.

john matthews, January 2006

if you havent sorted this problem out yet send me your email address and ill send you my phone number and ill try to talk you through the way to test and rectify this problem my email address is michaelhalliday4@hotmail.com

mike, February 2006

thanks for the reply
i fitted a new diverter valve yesterday,is the venturi inside the valve as on my diverter valve there is only 3 outlets all about 15 mill

john, January 2006

if you have the manual this could be a blocked venturi this is a small thin pipe that connects to your diverter valve as this is smaller than the actual hot water pipework when the demand is on for hot water the water passes past this pipe creating a positve force and enabling the diaphragm in the diverter valve to push out onto its microswitch if ther is a blockage in this it wont activate the diverter valve let me know how you get on

mike, January 2006