Despite having run over 50 gallons of water through the Seaward hot water heater on my boat, I'm still getting brown/rusty looking hot water. (It looks like coffee and cream!)Of course, it is worse after it has sat for a couple of hours. I've thought of disconnecting it from the water system, hooking up a garden hose, and flushing it for an hour or so. Any other ideas? Any chemicals that will help clean, without overly damaging the interior? From the manual, the inside is aluminum. Also, could the hotwater lines from the hotwater heater to the fixtures, sinks, shower, etc., be coated with the rust, adding to the problem? Thanks in advance.
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Justin - O'day Owner's Web
Flushing hot water heater . .
Ron, If the interior components of the water heater are aluminum, where is the brown water coming from? If you were seeing the effects of oxidization in the water heater the water would be showing either white or green. Is it possible that the discoloration is coming from the tank? What does your cold water look like? As far as flushing the interior of the heater, if you are pretty sure that is the source of the contamination, keep on flushing. I would try to rig the inlet so that the heater is directly downstream of the regulator so that the tank is isolated. I'd also rig the outlet directly overboard if possible. That will let you see when the water runs clear. DO NOT UNDER ANY CIRCUMSTANCES HOOK A SEAWARD HOTWATER HEATER UP TO SHORE PRESSURE WATER!! We had a customer by-pass the regulator, feed his Seaward shore pressure, and blow it out. Fortunately he was asleep at the time and heard his bilge alarm sound in time to stem the flow and let the bilge pump out. Had he gone ashore that night his mistake would have sunk the boat at the dock. YMMV Justin - O'day Owner's Web
Ron, If the interior components of the water heater are aluminum, where is the brown water coming from? If you were seeing the effects of oxidization in the water heater the water would be showing either white or green. Is it possible that the discoloration is coming from the tank? What does your cold water look like? As far as flushing the interior of the heater, if you are pretty sure that is the source of the contamination, keep on flushing. I would try to rig the inlet so that the heater is directly downstream of the regulator so that the tank is isolated. I'd also rig the outlet directly overboard if possible. That will let you see when the water runs clear. DO NOT UNDER ANY CIRCUMSTANCES HOOK A SEAWARD HOTWATER HEATER UP TO SHORE PRESSURE WATER!! We had a customer by-pass the regulator, feed his Seaward shore pressure, and blow it out. Fortunately he was asleep at the time and heard his bilge alarm sound in time to stem the flow and let the bilge pump out. Had he gone ashore that night his mistake would have sunk the boat at the dock. YMMV Justin - O'day Owner's Web
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Ron Dague
Justin - Cold water is clear
I agree that aluminum wouldn't give brown corrosion. But the cold water is clear. Thus, my confusion. Is it possible that the hotwater heater is mixing the engine circulating water with the water to be heated? But I'm having no overheating problem in the engine. I'll try flushing more tomorrow.
I agree that aluminum wouldn't give brown corrosion. But the cold water is clear. Thus, my confusion. Is it possible that the hotwater heater is mixing the engine circulating water with the water to be heated? But I'm having no overheating problem in the engine. I'll try flushing more tomorrow.
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Peggie Hall/HeadMistress
It may be rust, it may not be
How old is the water heater? Galvanized aluminum does eventually corrode, so it could be rust..or something could have have caused galvanic corrosion in it. As soon as you tell me how old it is, I'll check with a couple of my water heater expert sources and get back to you on this one.
How old is the water heater? Galvanized aluminum does eventually corrode, so it could be rust..or something could have have caused galvanic corrosion in it. As soon as you tell me how old it is, I'll check with a couple of my water heater expert sources and get back to you on this one.
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Jim Ewing
Cooling water
Ron, If the hot water is murky brown instead of clear brown you may indeed be mixing coolant. When we bought our boat the cooling water was a murky brown color. If your coolant is still green then it's probably not the problem. You can test this (subjectively) by tasting the hot water (just dip your finger, don't drink the swill). If you get a slight sweet taste that may be anti-freeze. Does the problem happen all the time or just when the engine's been run? Jim "Prospect" PS Did you get over to the Bahamas?
Ron, If the hot water is murky brown instead of clear brown you may indeed be mixing coolant. When we bought our boat the cooling water was a murky brown color. If your coolant is still green then it's probably not the problem. You can test this (subjectively) by tasting the hot water (just dip your finger, don't drink the swill). If you get a slight sweet taste that may be anti-freeze. Does the problem happen all the time or just when the engine's been run? Jim "Prospect" PS Did you get over to the Bahamas?
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Peggie Hall/HeadMistress
Excellent point, Jim...
I was thinking only in terms of AC only units...I didn't think about the possibility of a heat exchanger. If the exchanger coils in the tank have rusted out, or something else has failed that lets water from the engine circulate through the tank, that could very well be the problem.
I was thinking only in terms of AC only units...I didn't think about the possibility of a heat exchanger. If the exchanger coils in the tank have rusted out, or something else has failed that lets water from the engine circulate through the tank, that could very well be the problem.
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John Kudera
Isolate
Try and remove the inlet and outlet, connect them, run water thru the diverted water pipes, if it is not brown and rust colored, do yourself a favor and replace the tank. It is available thru West Marine, and relatively low cost, easy to replace. There are screws inside the storage bins,at the front inside, and two back a bit towards the hull side. Plywood top will then come off easily. Good luck
Try and remove the inlet and outlet, connect them, run water thru the diverted water pipes, if it is not brown and rust colored, do yourself a favor and replace the tank. It is available thru West Marine, and relatively low cost, easy to replace. There are screws inside the storage bins,at the front inside, and two back a bit towards the hull side. Plywood top will then come off easily. Good luck
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Justin - O'day Owner's Web
Even if the aluminum were corroded . . .
wouldn't the water be green? I've never seen brown aluminum oxide, but I defer to the expert on this one, especially as the cold water is running clear. The heat exchanger theory leads to another question, though. Why would you have rusty coolant on a freshwater cooled boat? Wouldn't something else have to be amiss? Diesel wisdom impaired - Justin - O'day Owner's Web
wouldn't the water be green? I've never seen brown aluminum oxide, but I defer to the expert on this one, especially as the cold water is running clear. The heat exchanger theory leads to another question, though. Why would you have rusty coolant on a freshwater cooled boat? Wouldn't something else have to be amiss? Diesel wisdom impaired - Justin - O'day Owner's Web
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Ron Dague
Update
Okay, I flushed another 30 gallons through today, it was clear. But I couldn't run the engine, so I haven't resolved the possible "coolant water - mixing with hot water" scenario. I will run it tomorrow and advise. Good suggestion about tasting the water, but I don't have antifreeze in my engine freshwater system, so that won't work.
Okay, I flushed another 30 gallons through today, it was clear. But I couldn't run the engine, so I haven't resolved the possible "coolant water - mixing with hot water" scenario. I will run it tomorrow and advise. Good suggestion about tasting the water, but I don't have antifreeze in my engine freshwater system, so that won't work.
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Jim Ewing
Rust source
The block on a yanmar is cast iron. If you don't use antifreeze (for it's anti-corrosion properties) or your anti-freeze is old then the water will start to pick up rust from the block.
The block on a yanmar is cast iron. If you don't use antifreeze (for it's anti-corrosion properties) or your anti-freeze is old then the water will start to pick up rust from the block.
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