I have a 2year old vaillant ecotec combi boiler there was a fault with the diverter valve which leaked all over the aqua switch replaced both of them the fault was ongoing before this but the customer let the boiler go out of warranty when you turn the tap on the boiler fires and goes to high flame the reaches 82c and modulates down and the hot water goes cold i have replaced the thermistor on the flow and hot water and after checking with vaillant the plate heat exchanger still does it evern tried the pcb still no good so put the old pcb back it is on lpg with good gas pressure no fault code is coming up and flow rate is what Valliant sau it should be 
Mant Thanks
Mant Thanks
