hot water stat should let burner fire at max 8mbar and min 1.5mbar. turn on tap, observe burner and when water starts to get hot slowly turn dhw stat down, it should give an audible click and burner flame should reduce, turn it back up and flame should go up accordingly. if it doesnt click then stat faulty, if it does click but flame size stays the same then modureg on gas valve maybe faulty.
paul martin, October 2007
