Replace Leaking Atwood (Seaward) Water Heater

I just noticed a very slow leak at the base of my water heater. I checked all other possible sources nearby and found no leaks so it is highly likely the heater needs to be replaced. Here is my question? I always thought marine water heaters are 110VAC. This one is 220VAC. I have found the same model online and am inclined to replace like-for-like because all of the connections are in the same location. Here is my question? Do I really have 220VAC? Can't think of why I wouldn't but just want to be certain. The unit was built in 2007 so 11 or 12 years in use doesn't seem to be a premature failure

Water heaters use an electric element that comes in 110V and 220V versions. So virtually every marine water heater can be had in either.


But some have replaced their 110V element with a 220V element but still run it on 110V power. That results in 1/4 the wattage of a 110V element It is sometimes done this way to limit the power draw for inverter/solar or to balance genset loads.


So that could be what you have. Is your shore power cord 220V? If not then you almost certainly have a 220V element running on 110V. But how do you know it is a 220V element?


David

Thanks so much for your quick response. My shore power cord is a common 2-leg 50 amp cord. I don't know if the heater has a 110V element. All I know is that the label says it's a 220V unit. I just looked at the electrical panel. The generator/shore power panel is supplied as follows:

Leg 1 - 2 16,000 BTU A/C units
Leg 2 - 1 16,000 BTU A/C unit, salt water pump, water heater

The water heater breaker is labeled 34-15 amp. So, I think, I think, the water heater feed is 110V. That would mean that I have a 110V element in a 220v heater. Now what?

djmarchand said:

Water heaters use an electric element that comes in 110V and 220V versions. So virtually every marine water heater can be had in either.


But some have replaced their 110V element with a 220V element but still run it on 110V power. That results in 1/4 the wattage of a 110V element It is sometimes done this way to limit the power draw for inverter/solar or to balance genset loads.


So that could be what you have. Is your shore power cord 220V? If not then you almost certainly have a 220V element running on 110V. But how do you know it is a 220V element?


David

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How many wire are going into the water heater. If it is 110 there will be a hot, neutral and ground. If it is 220 there will be 2 hots.

Comodave said:

How many wire are going into the water heater. If it is 110 there will be a hot, neutral and ground. If it is 220 there will be 2 hots.

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True but there should also be a ground on a 220 heater so the number of wires to the heater are not a good indicator.

Ken

I was referring to the number of hot leads, 1 vs 2.

The easiest way to determine is check the wiring. One green, black and white then it’s 110v. If two blacks and a green then 220v or if black, red and green then 220v. OP says there is one circuit breaker on leg 2, this is another indication that it’s 110v, to be 220v it would need power from leg one, unless it used a step up transformer, however 15a is not enough to step up 110v to 220v and run a heating element.

That is why I said check it at the water heater. It could be that the 2nd hot isn’t going through a breaker or it is on a mismarked breaker. I have seen things like this on boats that PO did some DIY wiring. When I bought my boat it had 2 30 amp inlets and only 1 30 amp breaker. President apparently wired the 2nd 30 amp service directly to the bus.

Once you decide exactly what you are working with, replace the breaker and any hinky looking wiring as well.

Please be careful when making assumptions from PO wiring. I have seen (and heard on these pages) of many instances of crazy or wrong color codes, faulty wiring setups and incorrect breaker configurations. Use a meter to thoroughly examine what voltages are where.

Ken

Or ask an electrician?

Water heaters can be expected to have a significantly shortened life due to corrosion if no air space is provided underneath and no hoses are connected to pressure relief valve or drain to lead dripping water away from the unit.

All my 220 volt circuits

catalinajack said:

Thanks so much for your quick response. My shore power cord is a common 2-leg 50 amp cord. I don't know if the heater has a 110V element. All I know is that the label says it's a 220V unit. I just looked at the electrical panel. The generator/shore power panel is supplied as follows:

Leg 1 - 2 16,000 BTU A/C units
Leg 2 - 1 16,000 BTU A/C unit, salt water pump, water heater

The water heater breaker is labeled 34-15 amp. So, I think, I think, the water heater feed is 110V. That would mean that I have a 110V element in a 220v heater. Now what?

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Are in one place on three breaker panel. Everything else is 110.

Gordon

djmarchand said:

Water heaters use an electric element that comes in 110V and 220V versions. So virtually every marine water heater can be had in either.

But some have replaced their 110V element with a 220V element but still run it on 110V power. That results in 1/4 the wattage of a 110V element It is sometimes done this way to limit the power draw for inverter/solar or to balance genset loads.

So that could be what you have. Is your shore power cord 220V? If not then you almost certainly have a 220V element running on 110V. But how do you know it is a 220V element?

David

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I thought David explained the situation very well.

In fact, I bought a 220v heater element so that I could run my water heater on 220v or 110v, while Dauntless was in Europe.

Most recently, I too had a small water leak that over weeks and months got bigger, so I finally had to replace the water heater.

Stick to your plan. And don't get sidetracked.

kchace said:

Please be careful when making assumptions from PO wiring. I have seen (and heard on these pages) of many instances of crazy or wrong color codes, faulty wiring setups and incorrect breaker configurations. Use a meter to thoroughly examine what voltages are where.

Ken

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Thanks to all who have responded. I opened up the access plate to the wiring. It's three wires coming in, red, black, and green, the color scheme one would expect for 220V, instead of black, white, and green for 110V. However, checking line voltage on the red and black shows only one lead to be hot, the red wire, which is consistent with the red wire at the breaker. I tested both wires directly to a big ground bus so I am now 99% certain I have only a 110v supply. What do you guys think? Have I missed something?

Yes, I understand that wiring 110V to a 220V element reduces current draw to one-fourth. This doesn't save any money, it just means a longer recovery time. So, since I do not have to worry generally about load-balancing, I am inclined to replace my 220V unit with a 110V unit.

Wxx3 said:

I thought David explained the situation very well.

In fact, I bought a 220v heater element so that I could run my water heater on 220v or 110v, while Dauntless was in Europe.

Most recently, I too had a small water leak that over weeks and months got bigger, so I finally had to replace the water heater.

Stick to your plan. And don't get sidetracked.

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Richard, I met you (and Julie) on the ICW, Isle of Hope in Georgia I think, maybe somewhere else, in early 2014 when you were bringing Dauntless north. We were new owners of a DeFever 44 and were bringing her north as well. You left the boat for a few days to attend a weather forecasting course. We were both approaching the docks one close behind the other, you in front but you requested that we go in first. You had those green LED rope lights strung around the bow.

While you are at it, I would replace the wiring so that is is color coded correctly. Or at a minimum, put tape on each end of each wire to reflect the proper color code. It will save time in the future if you or the next owner has to work on it.

Comodave said:

While you are at it, I would replace the wiring so that is is color coded correctly. Or at a minimum, put tape on each end of each wire to reflect the proper color code. It will save time in the future if you or the next owner has to work on it.

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Good idea. I'll tape the wires. Pulling wire back to the source just to correct the color scheme would be a major task. Tape will be a satisfactory indicator. I will also put a label on both the inside and outside of the access plate indicating 110V service.

Taping would be ok. I would double check and make absolutely sure that it isn’t 220. I always like to step back and think about it when something is strange and then make sure I am going in the right direction.

Comodave said:

Taping would be ok. I would double check and make absolutely sure that it isn’t 220. I always like to step back and think about it when something is strange and then make sure I am going in the right direction.

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Just double-checked as suggested. My first test was from red to ground bus bar. Next from black to ground bus bar. Red was live, black was not. Then, it occurred to me to test red to black to see if I had voltage. I did, 119V. That means my black wire is the ground in the circuit and I have, indeed, a 120V circuit. I will be purchasing a 120V water heater.

Did you find the black wire on your neutral bus bar? Sounds like a PO may have made some poor choices in wiring.

Comodave said:

Did you find the black wire on your neutral bus bar? Sounds like a PO may have made some poor choices in wiring.

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It was tough to trace through tight harnesses but I'm pretty certain that the black wire is on the green saftey bus bar. I will be ringing this wire out to make sure. Does it belong on the green bus or the neutral bus?

Well, if it is acting as the neutral wire then it should be on the neutral bus not the safety ground. Where does the green wire from the water heater go? If the neutral and safety ground are intermixed then you will have problems when you plug into a dock with ELCI breakers because some of the neutral return current will be going back on the green safety ground. I would ring out all 3 wires and make absolutely sure where each one is coming from. The neutral and ground should not be connected on the boat except when your generator or inverter is the source of your power. If you are not sure how to check this all out properly then get a certified marine electrician to check it. Good luck.

Comodave said:

Well, if it is acting as the neutral wire then it should be on the neutral bus not the safety ground. Where does the green wire from the water heater go? If the neutral and safety ground are intermixed then you will have problems when you plug into a dock with ELCI breakers because some of the neutral return current will be going back on the green safety ground. I would ring out all 3 wires and make absolutely sure where each one is coming from. The neutral and ground should not be connected on the boat except when your generator or inverter is the source of your power. If you are not sure how to check this all out properly then get a certified marine electrician to check it. Good luck.

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Yup. I need to ring out all three. You were correct. Bad wiring practice by a PO. The wires from the heater to the engine room switch are red, black, and green. From the switch they are red, black, and white. Can't be guessing. I just ordered a tone generator. I will get to the bottom of this and report back. I'll be turning off the breaker and confirming that the red is the supply all the way through the switch and to the heater. I think it is. Then the other two. It shouldn't be difficult.

Thanks so much for your counsel. I'll be back to report in a few days.

Good that you are doing this correctly. Comodave has already explained what additional problems you will have if wired wrong.

You have already found enough bad practices that I wouldn’t be comfortable until l knew were all the wires originate from.

It’s possible that things are wired correctly and the PO just used left over red wire. However, anyone who understands marine standards would have used white tape or labeled the wire so others would know that it was a neutral instead of a second hot. I’m concerned that some one who would use a red wire for neutral would also be ignorant enough to combine neutral’s and grounds on a boat.

A lot of the tone generators have such a strong signal that they bleed into other wires nearby. I have one and it bleeds into anything close so you can’t tell which wire is which. So I just end up ohming them.

UPDATE: I traced the wires. The original installation was wired properly. The neutral was NOT wired to the safety bus. The wire colors are all wrong but I will not be pulling new wire, far too difficult. I will, however, be using the proper color tape on each wire and write on the tape as well to alert any who follow me as to the wiring scheme. I will be installing (tomorrow) a new 110VAC water heater. Fortunately, the DeFever 44 engine room is rather spacious and the removal and installation is straight forward.

Thanks again for all who contributed and helped me understand the 220V vs 110V issue.

Glad you got it figured out. Now for the hard part, at least for me, doing the plumbing work. No matter how carefully I do plumbing work it always leaks...

Just finished installing the new 110VAC water heater. No leaks. Heats water to 142 degrees out of the galley faucet. Total success and not terribly difficult.

Good for you, want to come do some plumbing for me?