Seaward water Heater

[svchances]

Need trouble shooting help.

I had a new Seaward water heater installed two years ago. Worked perfect 1st season. Now it will only work on 110 / 120.
No matter how long I run the engine the water never gets much warmer than tepid. Used to be after 10 minutes it would be hot.
What went wrong??
Anyone that knows anything about water heaters......Please help.
Thanks

[HappyMdRSailor]

The likelihood of something being wrong with your actual heater is pretty darn low.... This is a circulation problem...

Any problem with engine temps?

1. Foreign object, kinked hose, or corrosion blockage
2. Fresh water pump going/gone bad
3. Air lock

[svchances]

Thanks for the advice.
Diesel temp is always good. No overheating.
No problem with fresh water pump as I do get slightly warm water from the heater after four hours running the motor; so something is getting through. Both in and out hoses are hot. Is there any kind of bypass mechanism?
Just asking.

[a64pilot]

Both hoses are hot, on the water heater end, or engine end?
Are you where you can disconnect the hoses from the engine end and flush with a garden hose?
I mean about the only thing it could be is no water flow through the heater

[Cheechako]

Yeah... look closely for a kinked hose. Were the hoses new when the heater was? IF not... sometimes hoses break down internally and one layer comes loose blocking the hose...

[svchances]

Thanks for the good advice. Tomorrow I will give all suggestions as fixes. Worst that can happen is I replace the hoses. This is why I like this Forum.

[GILow]

If both the input and output hoses to/from the unit are hot then this implies that the heat is not exchanging inside the unit. From my limited experience of these systems I would expect the return hose to be warm but not hot. Otherwise I was going to make the same suggestion I made on a recent thread which was to back flush the heat exchanger circuit as it may have become blocked up with crud. Simple process. But if it were blocked I would expect a very high temperature difference between the input and output hoses.

Matt


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[a64pilot]

I'm thinking they are hot at the engine, from simple conduction, but if I'm right if he checks the waterheater, neither hose will be hot.


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[Opie91]

Originally Posted by svchances

Thanks for the advice.
Diesel temp is always good. No overheating.
No problem with fresh water pump as I do get slightly warm water from the heater after four hours running the motor; so something is getting through. Both in and out hoses are hot. Is there any kind of bypass mechanism?
Just asking.

Is the highest point of the cooling system (including the hot water heater) the heat exchanger on the engine or the hot water heater? If the hot water heater is higher it will be difficult to bleed the air out unless you installed a header tank.

[GILow]

Originally Posted by a64pilot

I'm thinking they are hot at the engine, from simple conduction, but if I'm right if he checks the waterheater, neither hose will be hot.

Sort of... but when we had this problem on the Halvorsen Cruiser we hired, the hose from the engine to the hot water tank was very hot, but the return was frigid. It threw me for a moment then I realised it made sense, there was flow, just very, very slow flow. So all the available heat from the circuit was being extracted by the heat exchanger, as it had too much time to make the exchange.

Interesting point about the possibility of an air pocket in the heat exchanger Opie91. When I build my diesel fired system I will need to keep that in mind.

Matt

[GordMay]

FWIW: From the Manual ➥ http://www.defender.com/pdf/Seaward_...s_Install2.pdf

“... This water heater tank and heat exchanger is made of aluminum.
Some engine manufacturers recommend that cooling system be flushed periodically. Caustic chemicals are commonly used.

DO NOT flush caustic chemicals (such as Nalcool) through your system with the heat exchanger hooked up or damage WILL occur to heater.

If flushing is required by your engine manufacturer, you must isolate heater from this process. After system flushing is complete and neutralized, you can then re-plumb heater. Make sure recommended automotive type premixed ethylene glycol coolants such as Prestone, Xerex, or Peak are used for replacement ...”

[HappyMdRSailor]

Good catch Gordo...

Hope ya get some fun time with the boat today... find out why your flow isn't flowin'... It will also give you the chance to change your coolant (and flush) out If there's no obvious restriction... As A64 says run a hose to one end of the heater exchange loop... Same thing with the engine...

Good luck!

[cabo_sailor]

I had the same problem and it turned out it was the engine a Westerbeke 46. There is a diverter on the engine that is nothing more than a thin piece of metal inside a cast housing. It turned out it was broken, I removed it and replaced with a new one and no more problems. If that is your problem, buy several, the metal is quite brittle and I broke a few until I realized it had to be hand fit. I used a Dremel with a grind stone until it fit snug.

Hope this helps,
Rich

[svchances]

a64pilot. You are right. I checked the hoses at the engine and they are hot, but cool at the heater. I have decided to replace the hoses. From all the advice I have been given, I'm thinking that will solve the problem (blockage) as it is a new tank and did work. And it works perfect on shore power!

[a64pilot]

It could be the hoses, but I bet the heat exchanger is clogged, I'd disconnect both at the engine, and connect a garden hose to one and see if you get good flow out of the other. If you don't before doing anything else connect the garden hose to the other one to see if that flushes the clog out.
If the water heat exchanger is clogged, may be time to flush the engine as of course the same coolant runs through both.
Personally I am not a fan of chemical flushes, I try to flush things out with lots of clean water and keep flushing to only clean water comes out, drain as much as you can, fill with pure antifreeze until your sure of at least a 50/50 mix, then fill with clean water, some use distilled, where I live the water is very hard with lime, so distilled isn't a bad idea, can't hurt.

I don't know anything about a diverter, may ought to check into that


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