I should listen to my own advice and drained my water heater. As when I returned and the water had all melted in the pipes after I had lit the fire. I discovered that the water heater heat exchanger had burst. It leaked water all over the place all over the bed and in the bilges. It turns out the cost of a new heat exchanger is all the same price as a new one. So I am going to have to buy a new one and butcher it to repair the other. It has caused nothing but trouble today trying to sort it out. I also don't have any water as I can't use the water pump. I won't be able to sort till Sunday and I will have to go swimming just to have a shower.
So next time you stupid boy drain your water heater.