Looks as if your diverter valve has bitten the dust.
Vailiant do repair kits, though best off fitting a new one.
Its either the plastic arm, microswitch or diaphragm
Sounds like diverter valve mate. Located in bottom right of boiler, sometimes the microswich fails or you can buy a referb kit with new diaphragm. Watch the arm move when someone switches the tap on.
I suggest calling Vailiant tech line as they'll give you more advice for free.
Hi all,
Hope someone can be of assistance...
I have inherited a geriatric alarm system in our new house.
I would like to have the possibility to set the alarm to chime when opening doors etc.
Does this system have the functionality, as I'm trying to find this in the numerous manuals...
Could it be the flame picture electrodes that need adjusting?
Had similar fault on same boiler and engineer gapped to 4mm and worked ever since (touching wood).
Had similar problem. Turned out to be the small plastic armature on the bottom right-hand side of the diverter valve that hits the microswitch to call for hot water.
NB this isn't the flow switch/microswitch at the top of the diverter valve as I fist thought.
£1.50 fix off e-bay and no...