how can i fix my Vaillant Turbomax 824E plus?

thanks for reply carefree,but maybe didnt explain my testing,I actually had 240v at boiler terminal block across L and N and had also already ascertained fused switched supply was good.It was only on actuall turning boiler on at on/off switch on boiler that problems arose

sparkwort
February 2011

May I respectfully suggest your testing methods may be a bit awry?
If you have 220-240v at the mains block, you can only establish this correctly testing between L&N. If, as you say however, your neutrals are also live, you cannot establish 220-240v between L&N as you are measuring potential difference and your reading therefore would be 0v

Do not rely on L&E or N&E to give you readings, this alone cannot determine polarity.

Please turn the thing off (for your own safety) and get someone in who knows what they are testing.

Carefree
February 2011