valliant combi could only get intermitant hot water at first . then only get hot water with heating on . now only warm water then goes cold then piping hot for a few seconds then cold again

ken, July 2008

you need to specify the exact vaillant boiler model, hot water problems usually come down to either flow switch, or diverter valve, or diaphram or thermistor
could cost you 10-200 pound in parts.
call our gas spares shop with the exact boiler model and we can give you prices of parts its 01273 673800

chris gas, July 2008