Greetings one and all. Whilst in the process of changing the anode and heating element in my van today I noticed there is a valve in the water supply line from the tanks. I don't remember coming across any information in the Jayco "paperwork" about what it is for. It seems to connect the two tanks into the water supply for the van and I assume, because it has an arrow on it, that you can select front, rear or both tanks but that is only a guess. Has anybody actually worked out what it does? Does the arrow mean what I think it does? Any opinions, funny or fair will be appreciated. Cheers Mike.