Aye av got the valve as well dave and yes it's from PF,this method of heating the water will suit me a lot better as I have added another valve before pumps so I can fill backpacks by gravity,so will now be able to get hot through the gravity fed hose if that makes any sense ::)I take it it's the radiator hose you are running from ext port back to tank,are you able to shut back doors when re-circling the water?