I woke up last night to the sound of the fresh water. I'd left the
switch on and it started in the middle of the night. The pump was
running dry and the water tank was empty. There isn't a
corresponding amount of water in the bilge and I couldn't find any
sign of a leak so I'm trying to figure out where the water went.

The pump has always cycled about every 10 minutes so I've been
thinking there must be a small leak somewhere but I never could find
it. We have the standard minimalist set up with a Jabsco PAR pump and
pressure switch and no accumulator or tank.

We have an Atlantic Marine hot water heater with the engine cooling
water running through it. One possibility is that the heating coil in
the tank corroded through and the water is leaking into the engine
cooling system and down the exhaust. The big concern here would be
filling up the muffler and then having water back up into the cylinder
with the open exhaust valve.

Has anyone heard of these heating coils developing leaks? Ours was a
fresh water boat until last season so it doesn't seem likely but it's
the only place I can think of the water going.

I'll turn the engine by hand or check for a high water level in the
muffler before starting the engine but I'd like to know if there is a
precedent for a leak in the heater coil

--

Roger Long