Water heater that is. My phone is too smart some times.

 

Anything that is sealed has seals and seals can always leak.

But a rotten egg smell is normally sulphur compounds, given off by anaerobic bacteria decomposing something in the absence of oxygen. Typically wafting out of the head, when seawater has been allowed to stagnate in the system and the bowl.

Could be you've got a similar puddle of stagnant seawater back there, with some mud or crud at the bottom, busily liberating the sulfur compounds. And just coincidentally located by the (engine heated hot water?) heater.

 

As Hellosailor mentioned, anaerobic bacteria often causes the rotten egg smell in hot water heaters. It's easy enough to get some bleach into the water heater, let it run through all the lines and then let it sit for a few hours. It'll kill the little buggers, at least until the next time they regenerate.

 

Might be better off with sodium metabisulfite (?) found at brewing supply stores. Non-toxic to us after rinsing, no harsh smell, and it won't damage copper or aluminum tubing in the heater.

Then again, a couple of flushes letting the water inside get scalding hot might do it without any chemicals.

Still, that should be "seamless" metal tubing inside with minimal places for anaerobic bacteria to set up camp, let alone to leak out from. Or is it just a 20-year-old heater in need of serious work?

 

Funny that this just appeared here because I just this week did the Clorox treatment at home after a slight sulfur odor appeared. Some years I get the problem and some years not. Seems to be random. Needless to say, the chlorine needs to be thoroughly flushed afterwards. You can actually see a cloud of yellowish dead bacteria in a glass jar of the treated water when flushing the chlorine out. It does not take much chlorine to zap 'em, maybe 1/4 cup, put directly in the heater. I turn water off, drain the heater down a bit and then pour some Clorox in the house filter, turn water back on, run hot water side through all the faucets until I smell chlorine, then let it set for a few hours before flushing out. Works 100% of the time and have never needed> 1 per year. Many people think they have bad well water and spend lots of money for fancy treatment gizmos when in fact it's just an easily flushed water heater.

Good idea about the beer bottle cleaner.

 

In order for the smell to come out of a water heater, you must have sulfur in your water, which then gets converted to hydrogen sulfide with the nasty smell. But... you have to ask a very important question: Does your hot water have the rotten egg odor? If not, the smell has to be coming from the head or the holding tank.

 

Check with your sailing companion(s). Sounds like the result of overindulgence on cheap beer and deviled eggs.

 

We just bought a Catalina 42 last weekend and are living aboard.

Any chance the holding tank is getting pretty full ?

 

Actually, a likely cause is electrolytic. Have you replaced the zinc recently? Pull it out and have a look. This is a common cause.

Check the fresh water tank. If it is ONLY the heater, I vote the zinc is gone.

 

According to the manual, this model doesn't have a zinc. It's an Atwood EHM11-SM.

The rear tank does need to be emptied and I should probably rule that out. However, there was no odor when I checked the discharge port for the holding tank. I just think it's strange how the smell comes and goes. Seems to be triggered by higher temps.

 

So there IS a nearby holding tank, which must have hoses to a head someplace. If those hoses aren't top quality they may have gone permeable and the stink may be coming through the hoses themselves.

One test for that is to wipe the hoses down with some cleaner and water, then wrap them in an old rag/towel and overwrap with layers of saran wrap. Let it sit for 24 hours or longer. Now take the wraps off, and if the rags stink...you've got the problem.

 

Maybe the pervious owner kept chickens and some hid aboard under the holding tank.Likely caused the hoses to go bad.

 

So we emptied the aft holding tank went away for about two hours and now the smell is back. Pretty sure it's not the septic system; smells different.

Another strong possibility is the battery charger. It lives in its own little compartment, underneath the mattress in the port stateroom. It smells much stronger around this area. We turned-off the charger and will see if that changes anything.

 

So we emptied the aft holding tank went away for about two hours and now the smell is back. Pretty sure it's not the septic system; smells different.

Another strong possibility is the battery charger. It lives in its own little compartment, underneath the mattress in the port stateroom. It smells much stronger around this area. We turned-off the charger and will see if that changes anything.

If it's the hot water, you should have an unmistakeable odor as soon as you run hot water into the sink. If you have an overflowing or unventilated battery, that certainly will smell. Not only that but you may have explosive fumes which are not being vented as they should. That could be a bigger problem than bad odors!

 

have you looked for water/mold/gunk under hose etc that may be damp, I found my recent odor problem to be a very slow drip for my sea strainer that made a wet spot and growth under some hoses that I originally blamed the holding tank system for

 

I vote for the head hoses - they tend to eventually become porous and send the stench to some of the weirdest places in the boat. Ya never know.

Good luck,

Gary

 

Check your charger's voltage. If you are charging above 14.7V and "cooking" a wet cell battery it will produce a tremendous amount of odor.

 

A dead battery cell makes a 10 volt battery being charged at 14.7 .That might make for odour. You can recognize the difference between turnips and bad eggs,eh

 

A good explanation of "rotten egg smell":http://www.rheem.com/docs/FetchDocument.aspx?ID=442e1e42-1e4a-4ada-81db-9b030030f470

 

Nice well written article; but, most of the cheapy hot water heaters found on boats and RVs are made with ALUMINUM. The chlorine in the water attacks the aluminum (forming aluminum chloride).

 

Actually the water smells fine coming out of the tap... So I'm leaning toward the charger. It definitely produces a lot of heat. I will power up the boat and leave the water heater off. If the smell comes back it must be the charger and / or batteries.

 

.... or the heater is already begun to leak.

 

Definitely the charger / batteries. Smell came back within thirty minutes turning the power back on. All of the cells were full.

I'm wondering if I do have a bad battery, though. I had the battery switch on bank # 2. When I switched off the charger, I noticed the cabin lights got noticeably dimmer, and went out completely within about fifteen minutes. So I switched it over to bank # 1 and all the lights are nice and bright again. And according to the gauge, bank # 2 is at 7 volts.

I think the next step will be to test the charger on bank # 1.

 

In an earlier post you stated battery charger - are the batteries close to the charger?
As mentioned above, batteries produce explosive gases and shall not be close to anything that can produce a spark (as a charger).

Batteries do contain sulphur (acid), if you have an open battery bank then it may produce a stink.

Seems your battery bank #2 is toast. 7 V is far too low.

There are many possible origins of a stink on board. Now you have identified it coming from the batteries which is unusual. Most often it is the hoses, in particular those that are in connection with toilet systems. The shall (should?) be replaced every 5th year - if they are of the highest quality!

Good luck, and please keep us informed - one can always learn something new

ATB

J

 

I think I'm to the point where I need to hire a professional. The hydrogen sulfide is a real safety concern.

It's strange that we had no problem for the first 4-5 days. It only acted up after we moved to a different marina... a much newer one.

For now, we're leaving the shore power off to be safe.

 

A sulfur "rotten egg" smell comes from overcharging batteries. This produces hydrogen-sulfide, hydrogen and oxygen as gasses, as the charger cooks the battery. Hydrogen and oxygen combine readily in the presence of a spark, and go bang! Hydrogen sulfide is very poisonous, corrosive, flammable, and explosive... see https://en.wikipedia.org/wiki/Hydrogen_sulfide

I suggest that you REMOVE the dead battery(ies) (you can't charge that bank properly anyway), and look closely at the battery charger to ensure that it is not cooking the other battery bank. If you run the engine, and have this bank selected you will perpetuate the problem.

 

Nice...

I just followed my link above and found the following pictures which may help illustrate my concern for you regarding Hydrogen sulfide;

 

Same problem coming from hot water heater. Never knew there was a zinc in it. Pulled it out and it was entirely gone. Drained what was left in and installed new zinc. PROBLEM WAS GONE.

 

It turned out to be a bad battery which caused the charger to charge continually, producing the sulphury smell.

I didn't know this, but I actually have five batteries on board. Four regular sized batteries on one bank, and then a small auxiliary battery on another. I didn't even know I had it. So we disconnected that battery and the problem went away.

The other disturbing thing is that the electrician claimed that the other four batteries had dead cells as well. This doesn't make sense to me because they seem to be holding a charge just fine. We ran off of them for 2-3 days while the shorepower was unplugged.

 

I didn't know this, but I actually have five batteries on board.

Uh, you did have this boat surveyed before you bought it... Yes?