On a new Hotpoint Ultima HUI 612 cooker with induction hob. Going all right for a few days and then we got an alternate flashing F and A on all four hob indicator panels. Corrected it by switching off at the main switch for a few seconds. Any idea what that means? Also can only get one ring to accept a timer, then none of the others can be timed; is this how Hotpoint have designed it? Many thanks for any help.