Help With Nasty Odors when Flushing

[jeff356]

Experiencing unwanted nasty odors in the aft cabin after flushing the head although I can see or find evidence of any leaks or spills.

Have a Hunter 356 with a 1 year old Jabsco manual head, plumbed using Raritan hosing and vent loop by the head to PVC pipe back to a Raritan Electro Scan unit in the aft port locker that flows into the holding tank on the aft starboard locker.

Noticed the vent hose had a dip in it under the holding tank vent filter and removed the extra hose to make a straight run to the vent but have not replaced the holding tank vent filter since I have owned the boat, going on 4 years. Also noticed when going to throw away the cut out hose that it smelled so will look to replace that along with the filter.

Just not sure how the odors get in the aft cabin and foot of the companion way stairs if no leaks. Admiral getting fed up with nasty smells.

Any ideas or if on the right track.

Jeff

 

[Peggie Hall HeadMistress]

When a flush goes through hose, it puts pressure on the hose wall. If that hose has permeated with odor, that pressure will force odor out of it. So check all your hoses for permeation and replace if necessary. Check your PVC connections for any leaks...some red food coloring in a full bowl of water will make 'em easy to see.

And get rid of the vent line filter! It actually helps to create the very problem it's sold to solve because it impedes the exchange of air needed to keep the tank aerobic. Plus, if the tank has ever overflowed out the vent due to heeling or overfilling it, the charcoal will swell and block the vent. This would be an excellent time to do things: replace the vent line with a 1" hose and the thru-hull with an open 1" bulkhead fitting. That will also require a new 1" vent fitting on the tank, but that's actually easy to do, thanks to a li'l gadget called the Uniseal UNISEAL

I've written copiously on odors, causes and cures here in the 20 years I've been here...you'll find a lot of good info if you search the archives of the Plumbing and Sanitation forum (which is where this thread belongs)...you might also want to check out the link my signature. And I'm always glad to answer questions.

 

[Skipper]

When a flush goes through hose, it puts pressure on the hose wall. If that hose has permeated with odor, that pressure will force odor out of it. So check all your hoses for permeation and replace if necessary.

Interesting.
I have same issue as OP; only when flushing. We only use for #1, so that's the odor.
Although it's intermittent, and not there at all in cooler temps.
I always thought it was coming from the vented loop vent. It dissipates after a minute.
It's not there if I've recently run any enzyme odor product through it.
Head is 4 yo Raritan in new/clean condition. I replaced all the sanitary hoses and new tank last year. Except the discharge hose from head to Y valve. It's original 33 years old. But it looks fabulous, and I've put my nose to it (not while flushing) and no bad smell. But your statement makes me wonder....

 

[jeff356]

Had this problem over the weekend and also saw you reply this morning to another post and was hoping you would weigh in on this, so thank you Peggie.

As a note I had the Electro Scan out late last year to replace the Electrode Pack and those hoses did not really smell. In addition I also use K.O. and C.P. to try to keep the system clean.

Will check out the reading material also.

 

[Peggie Hall HeadMistress]

I have same issue as OP; only when flushing. We only use for #1, so that's the odor. Although it's intermittent, and not there at all in cooler temps.
I always thought it was coming from the vented loop vent. It dissipates after a minute.

If there's no air valve in the vented loop, it very well could be. The air valve threads into the nipple on the top of the vented loop...it only opens to allow air INTO a line through which liquid is being PULLED...doesn't allow any air--or anything else--to get out of a line through which air is being PUSHED.

Whether that's the source or not, it's not surprising that it isn't there in cooler temps...bacteria become increasingly sluggish below 75 F...below 60 F too sluggish to do much at all...become dormant at 40 F. That's why I rarely hear from anyone north of FL in the wintertime, but get covered up with cries for help to solve odor problems in the summer.

I replaced all the sanitary hoses and new tank last year. Except the discharge hose from head to Y valve. It's original 33 years old.

The average working life of any hose--fuel, water, sanitation, exhaust--is about 10 years because rubber and plasticizers dry out, causing the hose to become hard, brittle and prone to cracking. Failed old hoses connected to seacocks left open when no one is aboard is one of the top causes for boats to sink in their slips. So it doesn't matter how good it looks or whether it stinks, that hose has been overdue for replacement for 20 years...and so is any other hose on your boat that's much over 10 yrs old.

 

[Skipper]

If there's no air valve in the vented loop, it very well could be. The air valve threads into the nipple on the top of the vented loop...it only opens to allow air INTO a line through which liquid is being PULLED...doesn't allow any air--or anything else--to get out of a line through which air is being PUSHED.

Whether that's the source or not, it's not surprising that it isn't there in cooler temps...bacteria become increasingly sluggish below 75 F...below 60 F too sluggish to do much at all...become dormant at 40 F. That's why I rarely hear from anyone north of FL in the wintertime, but get covered up with cries for help to solve odor problems in the summer.


The average working life of any hose--fuel, water, sanitation, exhaust--is about 10 years because rubber and plasticizers dry out, causing the hose to become hard, brittle and prone to cracking. Failed old hoses connected to seacocks left open when no one is aboard is one of the top causes for boats to sink in their slips. So it doesn't matter how good it looks or whether it stinks, that hose has been overdue for replacement for 20 years...and so is any other hose on your boat that's much over 10 yrs old.

Thanks.
I'll check for the air valve.
And look again at changing that particular hose. It's about the only original.

 

[kloudie1]

Since it is only in warmer weather, is it the stuff in the intake hose fermenting and smelling up the place as ya flush? Try leaving the head on "dry" and flushing using fresh water (container water, or shower if it can reach, into bowl while flushing) and see if it stinks up the place the same..

 

[Skipper]

Since it is only in warmer weather, is it the stuff in the intake hose fermenting and smelling up the place as ya flush? Try leaving the head on "dry" and flushing using fresh water (container water, or shower if it can reach, into bowl while flushing) and see if it stinks up the place the same..

I always flush with fresh water from the basin. Only use intake when offshore.
It's a different type of smell.
Anyway mine is not a big problem. It's a rare and transient odor. Was merely curious regarding the previous related conversation.

 

[Rick D]

FWIW, with a well-treated tank and good hoses, the only smell I get materially from the vent is the first two or so flushes from the head after sitting for a week. After that, it's benign.

 

[Peggie Hall HeadMistress]

I always flush with fresh water from the basin.

If you'd reroute your head intake line to tee it into your head sink drain line, you could use sea water all the time except to rinse the sea water out of the system before the boat will sit. You'll find detailed instructions for doing that in at least a dozen of my posts to the Plumbing and Sanitation forum...they're also included in my book.

 

[Skipper]

If you'd reroute your head intake line to tee it into your head sink drain line, you could use sea water all the time except to rinse the sea water out of the system before the boat will sit. You'll find detailed instructions for doing that in at least a dozen of my posts to the Plumbing and Sanitation forum...they're also included in my book.

The intake section has never been a problem. Another suggested it might be but it's not.
I only use fresh water from the basin (using a cup) to avoid hose calcification.
Anyway I'm loath to modify original things. Especially when the working space under the cabinet is about 1 foot wide by 2 feet deep, and filled with hoses and seacocks. I've replaced hoses and serviced seacocks in there on multiple occasions, and cutting and fitting a tee in 1.5" hoses in that miserable space doesn't seem worth any benefit, which isn't needed in this case.
But it's a great concept for other circumstances.

 

[Kings Gambit]

My response to head odors has been, to a degree; but certainly is now--replace the sanitation hoses first and get it over with. You just do not appreciate how much stink they can put out until you remove one, lay it on the dock, and then walk by it. After that you might be able to track down other contributing factors. Face it, most folks it seems do not know how to take good care of a boat, and marine sanitation is among the most neglected of all of the systems.

 

[Skipper]

My response to head odors has been, to a degree; but certainly is now--replace the sanitation hoses first and get it over with. You just do not appreciate how much stink they can put out until you remove one, lay it on the dock, and then walk by it. After that you might be able to track down other contributing factors. Face it, most folks it seems do not know how to take good care of a boat, and marine sanitation is among the most neglected of all of the systems.

Yep. Been there. They stink more on the dock... Because the ends are open.
The discharge hose I took out of my previous boat when refitting after purchase was down to about .30 caliber, from 1.5". Calcification.
Stank. Weighed like 20 lbs.
But all was fab for the remaining years I owned the boat.
Replaced all gear on current boat, except one hose, and it's the only problem. Slight problem, but still matches your theory: just toss it all.
Although that hose will be a giant pain for location and cabinetry reasons. So I'll put it off until it's more than just a very minor thing.

 

[Kings Gambit]

I'm a little big myself to be trying to get both hands around a hose with funny twists and loops deep inside the head cabinetry; yes--PIA. But--well, you can always hire it out. You want the wife out on the boat with you; then you gotta do what you gotta do. A heat gun helps to get 'em off and back on, but you have to be careful not to melt the hose!!

 

[chuckwayne]

the jabsco macerator on the 356 is mounted just inboard of the tank directly behind the access hatch in the aft cabin and it's attached to the bottom of the tank by a short hose. It's always wet with the stuff in the tank which is very corrosive - they often rot out just after the warrantee expires and leak - and really stink up the aft cabin; don't ask me how I know! it's a bear to replace - hard to get eyes and hands into that spot. I moved mine up and over, behind the swim step so it stays clean - the entire Gulf of Maine is a no-discharge zone so it's useless anyway.
I'd check that - if you have an inspection camera it's much easier to look down there

 

[jeff356]

Thanks for the reminder, I'll check again but did replace the macerator last season and thought I checked it.
And yes that was a nasty job, no matter how well pumped out and how careful it was a big cleanup.

 

[Peggie Hall HeadMistress]

Thanks for the reminder, I'll check again but did replace the macerator last season and thought I checked it.
And yes that was a nasty job, no matter how well pumped out and how careful it was a big cleanup.

It wouldn't be if you not only pumped out, but also THOROUGHLY rinsed out the tank and the overboard discharge plumbing and macerator pump before you start (which you should do 2-3 x a season--and especially before winter or other extended layup--anyway to eliminate any sludge). Put a disposable aluminum pan or a plastic trash liner under the hose connections to catch any spills.
And btw, heating hoses does make 'em a lot easier to remove and also replace...a blow dryer is less likely to melt the hose than a heat gun. I always kept a little travel dryer in my tool box just for this purpose. A little K-Y to lubricate makes getting hoses onto connections a LOT easier.

 

[jeff356]

Reason the macerator was being replaced was it was frozen and would not run, wanted the ability to dump tank if in appropriate location. Do rinse out the holding tank with fresh water every time we pump out and then pump dry again. Also as we have the Electro Scan so will run the macerator when out and about a few times in the year.
Tried large green trash bag but pans definitely sound better.
Use the hair dryer on all hose changes as it really does cut down on frustration, high blood pressure and busted knuckles. Tried that hose tool that has a U bend but it just tears up the end of the hose if really stuck.

 

[Peggie Hall HeadMistress]

The discharge hose I took out of my previous boat when refitting after purchase was down to about .30 caliber, from 1.5". Calcification.

Flushing with fresh water is about the only way to prevent sea water mineral buildup in a TANK discharge hose. However, a cupful of distilled white vinegar once a week will prevent it in the TOILET discharge hose. Flush it undiluted all the way through the system...after about 45 minutes follow with a couple of quarts of clean FRESH water. Do NOT leave vinegar sitting in the bowl...it causes soft rubber--joker valves are soft rubber--to swell and distort.

Do rinse out the holding tank with fresh water every time we pump out and then pump dry again.

There's nominal rinsing...and then there's THOROUGHLY rinsing. And I'd bet $1 that you're only nominally rinsing 'cuz that's all most people ever do, if they even do that much. Unfortunately that doesn't flush out much if any sludge or the macerator pump and plumbing.

To thoroughly rinse out a system, pump out and then put at least 6" of water into the tank via the deck pumpout fitting 'cuz that sends the water into the tank at the bottom to stir up any sludge and hold it in suspension so it can be pumped out. If you're at the pumpout, pump that out...repeat...repeat...till you're pumping out clean water. Then add water one more time and turn on the macerator pump. while you keep the water running.

This can be done with sea water if you have a washdown pump and can get outside the "3 mile limit:" Open the deck pumpout cap and use the washdown pump to put about 6" of water into the tank...the start the macerator pump while you keep the water running. About 5 minutes should give you a thoroughly rinsed system.

 

[Don Lucas]

I did all the things suggested and still had a smell in the aft berth. I finally (after 5 years) figured out that the smell was from the vent outside and when I opened the hatch in the aft berth that opens into the cockpit that the wind swirls around and the odor from the vent comes with it. If I shut the hatch the odor goes away. Leaving the hatch closed wasn't a good answer, but a vent filter was. I don't care that a well operating hold tank doesn't smell "as bad" it still stinks!