Seaward Hot Water Tank

[Tucson Sailor]

The pressure, fresh water system on our 1996 Cat 30 MKIII has slowly lost pressure over the last few months and the pump runs frequently. The stream from the various faucets has weakened. So I replaced the water pump. After reopening the two tank valves, the pressure from the cold water side is strong now and back to normal. However, the pressure from the hot water side is not normal. When the faucet is first opened there is an immediate burst as though pressure is being relieved. It then reduces to a trickle even though hot water eventually appears.

We have the 6 gal Seaward water heater tank under the quarter berth and forward of the fuel tank which has worked fine. I went to the boat (which is 2 1/2 hours away) to examine the hot water tank.

I removed the cold water intake, turned on the water pump and there is pressure into the tank.
I opened the drain hose bib and turned the pump on. Again there was pressure as water drained out. So I think the inlet check valve is OK.
I removed the outtake hose from the nylon bib near the top of the tank and there was a little pressure coming from the tank.
I removed the outtake nylon bib and ran my flexible snake inside the top portion of the tank to scrape away any deposits. After reassembly there was a slight increase in pressure from the tank.

The hot water does eventually work its way to the galley sink albeit at a dribble so the heating element is working.

I was think about turning the outlet nylon bib to point it up and then fill the tank with as much vinegar as it might take. I’ve done that with heat exchangers before and it couldn’t hurt to try it.

Any thoughts about what to do with this hot water heater?

Thanks,
Tim

 

[TimFromLI]

If you have pressure at the inlet, there could still be a blockage inside the inlet. My Raritan was leaking on my 93 beneteau. I will be replacing it this spring. The raritan has an anode built into the inlet. Maybe the seaward does too. Could be that the inlet is blocked by a corroded anode. If I recall, the seaward has an aluminum tank which don't last as long as the stainless tanks or raritans coated steel tank. The raritans fits and lasted 29 years so I will stick with it. If you got 26 years out of yours, it may be time. I think you have exceeded the life expectancy of a the tank.

 

[Tucson Sailor]

Thanks Tim,
You're probably correct about the life of the tank. I'll contact Seaward as well.
Regards,
Tim

 

[jssailem]

When I bought my boat, the Seaward water heater didn't function. Looking at the unit it appeared greater than 10 years old. Multiple years older. I researched and found a suitable replacement. The Seaward was retired. The new unit has served well providing heated water on demand. Happy Crew.

 

[Tucson Sailor]

Thanks John!

 

[Hayden Watson]

I needed to replace the Seaward 6-gal on my 1988 in 2006 so you have gotten a good long life out of it. Mine started leaking from inside the box and there were some places on the bottom of the exterior box that had rusted through. On mine, I was able to get it out through the drawer cabinet to port of the companionway after removing all of the fittings from the tank and the drawer frame.