Water is running hot then cold - Vokera Linea Bolier?

if it's a linea 24 or 28, what you could do to test it yourself is with the hot tap open and the burner ignited, watch the burner through the inspection glass and when the burner goes out and the water still running from the tap than quickly turn off the cold feed to the boiler (black leve moves anti-clockwise to the 9 o'clock position) the led display will then display a temperature in excess 90degrees - if it does then your plate hat ecxhanger is blocked.

Big A
March 2009