Help with new head smell

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Cont31fa

Member
Joined
Jan 25, 2024
Messages
18
Location
Home Port Boca Raton, FL
Vessel Name
Knot Tide Down
Vessel Make
38 Mariner Seville ( Now Helmsman i think?)
I have 2 heads, both jabsco, that are supplied with fresh water to flush.

Recently when we flush the main cabin fills with gas/odor.

I verified my vent is not plugged and I can't seem to find a in-line vent filter. I jand over handed the entire plumbing for both heads to the holding tank. Didn't find any leaks etc and the lines are nice.and white so I don't think they are permeateing.

Looking for ideas.

Thanks
 
If there's a vent filter, it would be after your holding tank and before the vent. Have you inspected all the way along the vent line? Your symptom could be a vent filter needing replacement.

Or Peggie will advise vent filters are evil :) and should be removed anyway. I don't think we've ever experienced what she describes about them, though.

-Chris
 
Install a "bubbler", small air pump to pump air into the holding tank.

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I usually change mine every 5-6 years. First thing I do when I buy a new boat. They are fresh water flush but I always find calcification in the lines. Seems to fix the odor issues.
 
Is the smell something that just started or is the boat new to you?
Important to differentiate source of smell... coming from tank via vent, from the bowl on initial flush after sitting unused, general area with any hoses. Is the cabin that smells near vent & window/door open?

How.old is the boat / hoses?
To check for permeation wrap hot wet rags around hose, cover with saran wrap.and leave overnight. Unwrap and smell the rags... you.will know.
 
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If the hoses are original, installed by the builder, they're the most likely source of your odor. The builder must have used higher quality hose than most OEMs, to last 16 years--6 years past marine hose "use by" date--is amazing! I know of only one sanitation hose that can do that: Shields Poly X...and they accomplish that by coating it in polyurethane...iow, they "varnish" it. If yours has a hard coating on it, that's what it has to be...the hot wet rag test won't work on it...it's stinking because the
"varnish" has cracked. It may not be Poly-X...the builder may have created a knock-off. No hard coating, I have no idea why it could have lasted this long without becoming hard and brittle. I do know that there's only one cure for permeated hoses: new hoses. But first we need to know whether permeated hoses are the culprit.

There's a simpler way to test 'em for it than Bacchus posted:
Wet clean rags in water that's as hot as you can handle. Wrap each section of hose with a separate rag. When the rags have cooled, remove each one and smell it...if you can't smell anything, that section hasn't permeated...if you can, even faintly, it has.

--Peggie
 
If the hoses are "permeated" wouldn't they stink all the time? Not just when the heads are flushed?
 
Also check the vent hose for any cracks. I would not bother checking the discharge hoses, just replace them and the vent hose. They are past end of life. I like SaniFlex hose. Defender sells it by the foot. If you do have a vent filter get rid of it.
 
I have 2 heads, both jabsco, that are supplied with fresh water to flush.

Recently when we flush the main cabin fills with gas/odor.

I verified my vent is not plugged and I can't seem to find a in-line vent filter. I hand over handed the entire plumbing for both heads to the holding tank. Didn't find any leaks etc. and the lines are nice and white so I don't think they are permeating.

Looking for ideas.

Thanks
Is the holding tank under the main cabin. I am suspecting loose hose connection And a plugged tank vent. The pumping action input is greater than than the vent output, thus gas in the boat from the hose connection at top of tank.
 
.......this thread reminds me why I went with a Compost Head (Peggie Hall justifiably calls them a Litter Box). Hard to believe, but outside of emptying the urine tank (which admittedly can take your breath away), there are no odors - no hoses to periodically change, no hose clamps, no tanks to leak, no pumps to fail, no vents to clog, nothing. Even "library time" is surprisingly non-odiferous. Unquestionably there are disadvantages to a compost head, but for reliable long term low odor, score one for composters.

Peter
 
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Yes followed from tank to vent connection and there is no filter.

OK, then...

Have you been treating the tank regularly with something like KO or NoFlex?

And then there's all that above about hoses or fittings...

-Chris
 
.......this thread reminds me why I went with a Compost Head (Peggie Hall justifiably calls them a Litter Box). Hard to believe, but outside of emptying the urine tank (which admittedly can take your breath away), there are no odors - no hoses to periodically change, no hose clamps, no tanks to leak, no pumps to fail, no vents to clog, nothing. Even "library time" is surprisingly non-odiferous. Unquestionably there are disadvantages to a compost head, but for reliable long term low odor, score one for composters.

Peter
I've had the same experience with our composting head at our off grid cabin. No odor, no piping, no hassle. Fingers are crossed for a hassle-free future with our marine heads as they have been good so far, but replacing hundreds of feet of hose would likely tip the balance. Is that something you guys do yourself or pay a yard to do?
 
If the hoses are "permeated" wouldn't they stink all the time? Not just when the heads are flushed?
Eventually, yes. But permeation begins with the first flush, not noticeable until enough flushes have gone thru the hose to saturate it. Flushes put pressure on the hose wall, so the first noticeable odor will be during a flush. As the hose becomes more saturated it'll begin stinking full time. The cheaper the hose, the faster it'll happen. Flexible pvc (cheapest) hose permeated on my last boat in less than 90 days. Strangely, same hose had been on my previous boat for 7 years without a trace of odor. Better quality hoses were just being introduced by SeaLand and Trident then...I replaced with SeaLand "OdorSafe," which was then being made in Australia and highly permeation resistant. SeaLand dumped the Aussies for a cheaper supplier with predictable results.
This was in the '90s...If my memory serves me correctly Raritan introduced SaniFlex in 2012....I watched it for a couple of years, looking for boat owner failure reports before beginning to recommend it....I have yet to see a single one.

---Peggie
 
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If you’re getting odor when flushing, and no other time, it’s almost has to be the vent. Someone mentioned no flex. It’s a good way to keep odor down in the tank itself. Another mentioned a bubbler, that’s a fantastic idea as well.
I had a problem previously where my vent fitting is close to the drain for one of the sinks. If the tank was ripe, and the wind was just right, the odor would be pushed up the sink drain. It’s surprising how little air flow coming up the drain would bring the smell right in. I put my nose down in the sink after flushing, and wow, undeniably the source.
I started using no flex between pump outs and it helps considerably.
 
We had something like that happen on a previous boat. When the wind blew a certain direction the holding tank vent smell would come up the old unused shower drain. Took a long time to figure that one out.
 
I've had similar drain issues as well. We learned on our boat to keep the drain plug installed in the aft head sink whenever the sink isn't actively in use for that reason. In our case it's not holding tank smell, but if the generator is running and the wind is just right, you get exhaust pushed up that drain (it's about 5 feet aft of the generator exhaust, both a few inches above waterline and on the side of the boat). Keeping the plug in solved the problem and it's easy enough to just remove it, use the sink, and then reinstall the plug.
 
I think I solved my problem. Thank you to all that offered advice.

My forward head was dry so when flushing the aft head the forward head was acting as the vent. There may be a trap between the forward head and holding tank so with that being dry I was getting the air displaced in the holding tank during a flush vent out of the forward head.

Filled and flushed the forward head a few times and now the bowl holds water. Flush the aft head and no smell.
 
My forward head was dry so when flushing the aft head the forward head was acting as the vent. There may be a trap between the forward head and holding tank so with that being dry I was getting the air displaced in the holding tank during a flush vent out of the forward head.

Filled and flushed the forward head a few times and now the bowl holds water. Flush the aft head and no smell.

Both heads controlled by the same vacuum pumps, etc.?

Our are each separately controlled, independent systems until past the vacuum pumps...

-Chris
 
Both heads controlled by the same vacuum pumps, etc.?

Our are each separately controlled, independent systems until past the vacuum pumps...

-Chris
Each has its own pump. They are at different levels though
 
I agree. I just did a pump out and flushed 2 full hold tank full of fresh water. Then put in 10 gal of fresh into the holding tank and ran the macerator. When tank was empty the macerator was pulling through both heads?
 
The fact that your forward head was acting as the vent for the aft head makes me wonder if your vent line isn't plugged. Have you blown compressed air in to it? You may find it's plugged with spider eggs or something of that nature.
 
It’s likely the vent line is just undersized. They usually are. Easy to see how a dry bowl could pass the odor when the other head flushes. Doesn’t take much pressure to get those gasses airborne.
Keeping water in both bowls will fix it.
Using a powerful vacuum pump to pump out the tank, whether upland or macerator can indeed evacuate the water from the toilet bowls if the vent line is marginally sized.
Upsizing the vent line would be a good thing to do. Cant be too big.
 
undersized is subjective if this is a new occurrence. An overfilled tank can put a plug into the vent line, an inline filter once wet is also a blockage.
 
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