Toilet 'burps' after flushing solid waste-help Head Mistress!

[dbSail]

I am a new boat owner (well, I'm new, the boat isn't), and I am having problems with flushing solid waste. Liquid waste has no problems. When I go to the pump out (usually weekly) I always give the holding tank one or two rinses from the deck fill and often, if I have help, I run about 5 bowl-fulls of steaming hot water from the shower through with no problem. I have let vinegar sit in the lines for a few hours. I only use seawater to flush solid waste through, otherwise I keep it on dry bowl and pour a quart of fresh water in after every use and pump that through to keep it smelling fresh. I have put Marine Digest-It in several times since I got the boat 3 months ago.

The problem - when I flush solid waste, it seems to go through, but then the water level starts rising in the bowl. I wait a few seconds, then it 'burps' air (a big healthy burp). I pump a few more times, and it either all goes down, or I have to wait for another burp. Rarely waste will come back, but it's not right away - usually means I should have waited for the second burp. The handle feels fine - no unusual pressure. I would assume (maybe wrongly) that if the vent were blocked I would have trouble pumping liquid waste as well. I don't let the tank get full, and it's never been pressurized when I've opened the deck fill. The metal fitting from the vent hose to the vent corroded, so the open hose is sticking out of the lazarette vent right now until I can address that, so no screen or apparent blockage I can see (clear hose). I have been reading quite a bit, and am assuming the answer will be the joker valve or the hose from the toilet to the holding tank, but I wanted advise before I tackle an unfamiliar system by myself.

This may not matter, but there is a small leak when the Y-valve is turned to the tank - just a drop, but not when the Y-valve is turned to go overboard (this is not a habit, just an experiment). That makes me think that the hose from the Y-valve to the tank may be full of calcification? If so, is vinegar enough?
Thanks.

[peghall]

Solid waste is at least 75% water, so it dissolves pretty quickly. Going through the pump breaks it up, which helps it dissolve even faster....which is prob'ly the reason why you can flush it through after the "burp"... 'cuz that "burp" means something inline is definitely "pushing back", and sea water mineral buildup is as good a guess as anything else. Vinegar will prevent it, but it's not the cure...flush a dose of muriatic acid through the system...wait about 30 minutes, then flush clean water and see what happens. If it doesn't cure the problem, I'm afraid you're gonna have to start taking things apart to find it.

[KISS]

First guess would be the vent is clogged.

Originally Posted by dbSail

I am a new boat owner (well, I'm new, the boat isn't), and I am having problems with flushing solid waste. Liquid waste has no problems.

It would only burp back air if the waste flowing into the tank were filling the whole pipe. If the pipe were only partially filled, there'd be a space for the air to escape, and no burp. Like if you drink slowly from a beer (no glug), versus pounding it (glug glug). I'm guessing you flush solids down with water, but not liquids? So there's less volume going down the pipe when you flush liquids?

I don't let the tank get full, and it's never been pressurized when I've opened the deck fill. The metal fitting from the vent hose to the vent corroded, so the open hose is sticking out of the lazarette vent right now until I can address that, so no screen or apparent blockage I can see (clear hose).

If it's burping the air back into the bowl, it's not getting pressurized.

Have you tried flushing it with the deck pump out line uncapped? If not, I'd try that. If you get no burping, then I'd say that means you're vent line is blocked.

DISCLAIMER: I have no actual experience with marine heads, but I understand how they work, and have shotgunned many beers. I also stayed at a Holiday Inn Express last night...

[dbSail]

Head Mistress - Thank you so much! On the search for muriatic acid.

Note that the toilet and new white smooth hose were installed about two years ago and the boat appears to have sat unused for those two years. The tank had a very small amount of liquid in it when I bought it - maybe 3" in a 35gal tank...but who knows what sat in the hose during that time.

KISS - this will be interesting...pooping, then running up on deck to open the deck fill, then running back down again to flush. Can't wait..... Funny enough I've been brain storming with a friend for a poop substitute b/c he wants to see what is happening...we've decided on mashed potatoes! I do flush liquids with water - I keep two gallon jugs of fresh water in the head to use after liquids-about a quart each time. I have zero burps with liquids - even a full bowl. When I use the Marine Digest-It I fill the entire bowl with warm water and let the MDI incubate per the instructions. I can hear the liquid going into the tank which is nearby when I pump.

Perhaps I can get something to attach to the vent hose at the outside and try to flush water through? There's no one way valve thing happening there right? The venting hose is probably 15-20 feet long from the holding tank. I don't think it is blocked b/c the way I discovered it had become unattached from the thru hull vent was that the cockpit smelled each time someone used the head so I checked the lazarette and found the end lying free and the corroded elbow that attached it to the vent.

Thanks for all the input. SO much to learn.
DB

[KISS]

Originally Posted by dbSail

I do flush liquids with water - I keep two gallon jugs of fresh water in the head to use after liquids-about a quart each time. I have zero burps with liquids - even a full bowl.

Hmmm....well that would seem to scuttle my glug/no-glug theory.

If you can tell, does the "burp" smell foul (like it's air that had been in the holding tank) or not (like maybe it just got pushed/pulled into the line somehow when you flushed it)?

Where else could air be getting into the system?

Perhaps I can get something to attach to the vent hose at the outside and try to flush water through? There's no one way valve thing happening there right?

Possible, who knows, people set up their heads in all kinds of ways. Heads are a bit like ground tackle - fierce battles over which set up is best.

The venting hose is probably 15-20 feet long from the holding tank.

Whoa! Whether that's the problem or not in this case, I think it would be wise to shorten that line if at all possible, so that it's easier to clean if there ever is a problem. Same goes for all plumbing - the shorter the better.

[dbSail]

KISS:
The Burps never smell, and they don't come bearing any gifts except on rare occasions. No idea where the air is coming from - no strange noises or leaks that Ive found.

The line is long because all the vents are on the transom (water tank, diesel, holding tank) and my head is just behind the v berth with the holding tank just aft of that on the other side of the wall. 32.8' boat.
DB

[KISS]

Only other source of air I can think of is a vented loop, if you have one.

Dunno, I'm flummoxed. Good luck sir!

[anchorman]

Listen to Peggy. She is an expert on marine sanitation.

[peghall]

[QUOTE=KISS;1659347]Whoa! Whether that's the problem or not in this case, I think it would be wise to shorten that line if at all possible, so that it's easier to clean if there ever is a problem. Same goes for all plumbing - the shorter the better.[/QUOTE]

It never occurred to me that the vent could be the problem because he was able to flush liquids with no problem. But KISS may have nailed it...a 15' vent line, especially if there are any bends in it, is WAY too long...it shouldn't exceed 5', shorter if possible. The air has to travel too far to make it on the first flush attempt...finally enough to relieve the pressure, allowing the second try to clear the bowl.

Move it and shorten it: You'll need a new vent thru-hull directly above the tank, or better yet a few feet forward of it to provide a shallower rise than straight up vertical. Use an open bulkhead thru-hull, not a "vent" thru hull...that will allow you to stick a hose nozzle against to backflush the vent line every time you wash the boat. If you heel enough to put the new vent under water, put a high clamshell over it to keep water out.

We should talk about the plumbing--head discharge line length and routing--too.

[dbSail]

I may have another piece of information. I did put a whole gallon of vinegar in last night to sit in the lines overnight just because I already had it. This morning I had trouble pumping liquids as well. For the first time I noticed the sound of the vent at the top of the loop. When I put my finger over the vent, everything went down much faster. I'm still reading Nigel Calders Plumbing section, and it looks like this is supposed to be there, but it was interesting that stopping it from sucking air made for much more efficient pumping.

Still plan on trying the muriatic acid. Changing the vent line won't be able to happen anytime soon unfortunately.

PS - I'm a she

DB

[CruisingKitty]

We had a toilet that burped. It turned out a U junction had so much build up that the opening was about 1 in wide. A rebuild did the trick. No more burping.

[Terra Nova]

Originally Posted by dbSail

I may have another piece of information...
I noticed the sound of the vent at the top of the loop. When I put my finger over the vent, everything went down much faster...

OK. The "burping" might be simply the column of water standing in the hose between the vented loop and the head. Once you stop pumping, water in the hose drains out, as it should.

[cwyckham]

Can you explain exactly what vented loops you have and where they are? It sounds like you have one before the Inlet pump. Or is it after the pump and before the bowl?

Do you have a vented loop in the discharge line?

Sent from my SGH-I337M using Cruisers Sailing Forum mobile app

[EveningTide]

I recently fixed a burping head. In my case the vent line was plugged. When pumping out the head liquid (or solids) go up and over a loop (where anti-syphon valve is located) and down into the tank. Water in the hose would then slowly pass the head's joker valve and refill the bowl. Then pressure in the tank would cause burping as air from the tank reached the bowl.

In your case liquids are OK but solids burp. Maybe your vent is 98% plugged. When I pump liquids I pump a little but pump a lot more with solids. You may build up just a little pressure with liquids but much more with solids. The vent is adequate when there is only a small amount of pressure but with solids the vent hasn't had time to reduce pressure before the liquid drains back into the bowl and burping begins. This is just a theory. (And its easier to trouble-shoot the vent than disassemble other parts of the system.)

[transmitterdan]

db,

Have you ever replaced the joker valve at the head discharge? If not, that's something you may want to look at. If the joker valve is working nothing should come back into the bowl after you pump it out. The back pressure from the standing fluid up to the anti-siphon should keep the joker flaps closed.

Vinegar left standing on some rubber compounds will deteriorate them over time. I think joker valves are usually made from one of these rubber materials that doesn't like vinegar. If you pull out the joker valve and look at the duck bills (2 or 3) and they are "wrinkled" that may be due to vinegar or some other acid.