Hot Water Heater Mark I (1991)

[Jim Price]

My water pump has started to breifly cycle when no water is in use.  Looked for leaks and found water accumulated on hot water tank shelf.  Appears that water is coming from either one or both engine water line connection points.  Water is clear (potable) so does not seem to be from leaky clamps (tight, not antifreez - green).  Very slow leak semms to be coming from INSIDE or AROUND fitting tube from tank (back side).  That could expain breif pressure drops, thus pump cycles.  Question, before I start taking everything out, has anyone had this type leak before? Is it repairable on the Seward tank side?  If so how, etc.  Or does this mean a new tank? I can see that I will need to replace or repair the shelf due to the water accumulation but trying to have a better game plan.

[captaingary]

You will probably find the tank itself is corroded through and leaking and I would not waste time trying to repair it. You will need to take the framework off on the side access door to get the water heater out. Once you have it out and take the cover off you will be able to see the problem.

[Jeff Tancock]

I too had a leak there. Just tightened the hose clamps and it was taken care of. I believe that mine only leaked when the water was hot and things expanded? Anyway, give the teflon tape a try.

[Ken Juul]

I had the same problem couple of years ago.  If you have the square Seward, I don't think the in/output for the engine coolant lines are nippled.  On recommendations from a couple boat yards, I bought a new one before I pulled the old.  I didn't disect the old one, but from the amount of corrosion present, I think it would have cost more to have it repaired than the cost of a new one.  I think the pressure, heat cycles, and a hard area to weld make this the weak area in the heaters construction.  Keep an eye on the Boat US/West Marine flyers, one of them usually have the heater on sale.  The other option is to plug the water input line and live without hot water till you get it fixed.

[Jim Price]

Thanks for the info.  I expected to find that others had problems with the tank or fittings also.  I will put this on my list for July -August when the winds are dead here in GA to solve.  Since I will need to rebuild / re-glass the shelf anyway, I will try your various solutions (depending on level of corrosion).  If I need to replace, understand the less expensive galvanized version is way to go (not in salt area)since insides are same.  This board is just great for folks like me that hate to pay a yard for anything!!  ;)