I have a ravenheat whitestar ls 100, lately the red flashing light is on all the time and we are lucky the boiler stays on 20 mins before its back on, I changed the heat stat as it says and i thought it was sorted but it only worked for about 2-3 hours before the fault started again, in the fault finding book it mensions to try the dhw/ch potentiometer, any ideas would this fix it, thanks

Jason, January 2015