Vaillant Turbomax 828E - Warm start problems?

[Gravesy]

I have a Vaillant Turbomax 828E Combi boiler which is about three years old now and have just started having problems with it and need some advice!

When the boiler is set to run with the warm start on, the heating fails to switch off even though it is on a TimeSwitch 100 timer. The only way to prevent this from happening and for the heating system to run "normally" and to the pre-set times is to turn the Warm Start off.

However, I have found that when the warm start is off, obtaining hot water from the boiler at times when the heating is off (i.e. during the day) is near impossible and I have to either reset the boiler or turn on the warmstart. Getting hot water when the heating is on (i.e. first thing in the morning and evening) is fine with the warm start off.

I hope this makes sense and someone is able to help me out with this problem. To summerise the main problem is:

When the warm start function is enabled, the heating system fails to switch off in line with the timer and is effectively running all the time. This does not happen when warm start is switched off.

Thanks to all in advance.

Ben

[Ed Sirett]

It all points to the diverter valve. A fairly easy component to exchange. Follow to the book.

[Gravesy]

Thanks for that Ed, I will have a look into the diverter valve. Any idea where I would get a copy of the book you refer to in your reply?

Ben

[Ed Sirett]

By rights you should have had one when you bought the house or had the boiler fitted.

No problem, just phone Vaillant on 0870 6060 777.

If you really really can't be bothered to do that then email me and I'll email you the pdf.