Odd HW problem with a VAillant 824 Plus boiler

[Ramses505]

To restate the symptoms -

HW cool if CH NOT running !

If I do NOT have the heating on - I turn on a HW tap and the water does not get hot, only warm. If I then turn off the HW tap and turn heating on via the timer (1 hour CH demand) then wait a minute or two and then turn on the HW tap, water gets hot like it used to do.

To clarify, I am not just getting the first 'flush' of hot water caused by the heating circuit having been run, but continuous HW to fill a bath.

 

[gas4you]

Apart from the fault, I take it you mean an Ecotec Plus 824, which in this case this will still be under the manufacturers 2 year warranty as they were only produced and available from around june 2005.

Turn your hot taps on full and press the i button it should read S14 in the display if everything is working ok, if not what does it read?

 

[Agile]

Ten times more likely to be a Turbomax Plus !

The diverter valve has probably failed as they all do after a couple of years.

However the symptoms as described do not exactly support that failure!

Tony