1. An internal leak in any calorifier engine coil but that usually causes water to keep pouring out of the engine filler because of domestic water pump pressure.
When we leave the boat we turn off the electric via grounding the 12 volt supply to fridge, pumps etc and isolate the water from the tank. When we return we obviously turn it back on but when we do I have noticed a slight increase in the domestic water pump, seems to be on more only for about 3-5 seconds then usual when it pressures back up. I have checked the calorifier, do I need to check it again?
I wouldn't want to change the water pump and or head gasket just to find out it isn't that. Changing the head gasket wouldn't harm though would it? Apart from harming my wallet.
Clutching at straws now!