STARTED LEAKING WATER, AFTER I HAD A LOOK FOUND IT WAS COMING FROM THE TOP OF THE UNIT, THERE WAS A SMALL PLASTIC CAP LYING BESIDE,LIKE A TYRE VALVE SO I SCREWED IT BACK ON THE LEAK HAS STOPED, HAVE I DONE THE RIGHT THING ,WHAT DOSE THIS ITEM ACTUALY DO?
the tyre valve is on your expansion vessel if you have water coming from the valve then the diaphram inside in split, you'll need to replace it, as it will cause problems