Holding Tank Question

[Dougcole]

Hey Guys,

We have a vacu flush head on our 2005 mainship 400 T. Recently I've been getting a little odor, and when I unscrewed the pump out deck cap, it seemed pressurized. Effulent and quite a bit of air came out around the cap, even though the tank was not full.

Clogged vent line maybe?

Thanks,
Doug

 

[Forkliftt]

Doug, I would think it has to be.

 

[jwnall]

Doug, I would think it has to be.

That would be my best guess also.

Your Morgan in Carrabelle yet? I saw a Mainship at C-Quarters the other day (had a dinghy on the swim platform so I could not see the name) and thought it might be yours.

 

[Dougcole]

Yep. That is it. Brought it up about a month ago.

 

[jwnall]

Yep. That is it. Brought it up about a month ago.

Whoa! NICE BOAT! I kind of thought it was yours, and spent some time looking it over. I still like the old Morgan, though, so no envy.

 

[RT Firefly]

Greetings,
Mr. D. Well, plugged vent line would be my first guess as well. Not hard to check. Remove cap (gingerly), put a water hose into the vent and give it a shot of water (to backflush). Double check that your tank is NOT full or you'll have more than egg on your face.
As far as the odor goes. A plugged vent will encourage the growth of anaerobic bacteria and that's NOT what you want. You want the aerobic bacteria. Them's the bugs that break down the waste with little odor. I hope you haven't been using those formaldehyde based head chemicals to control odors. BAD stuff!

 

[Moonstruck]

A friend had trouble with a Vacuflush system on a 38' Laguna. They had guests onboard as it was the opening weekend at the yacht club. He decided to go down and check it out, so in his Sunday whites he descended into the bilge. He took the clamps off a hose, and all hell broke loose. Needless to say that he was a sad sight, and no one could get near him or his boat. He learned the lesson of the plugged vent on a Vacuflush the hard way.

It can happen on other types of toilets, too. In Clearwater a friend had a plugged vent on a Heritage trawler. When he reached down to remove a mud dauber's nest from the vent, the force of gases brought him to his knees.

 

[beachbum29]

I used carb cleaner to remove the buildup on my vent valve. Works great now.

Put some white vinegar into your holding tank 24-48 hours before pumpout. It will help clear the sludge.

 

[HopCar]

Beachbum, What's a vent valve?

 

[sunchaser]

Why BAD stuff?

 

[RickB]

Clogged vent line maybe?

See if it has a vent filter installed. If so that is the most likely suspect.

 

[beachbum29]

Beachbum, What's a vent valve?

It's where the vent.hose connects to the holding tank. I was having problems even after I changed my filter. I pulled the hose off the tank and it was plugged shut. It appeared that it had some type of flapper valve inside.

 

[denverd0n]

Why BAD stuff?

Because they kill the aerobic bacteria in the process of (temporarily) suppressing odors. You WANT aerobic bacteria. That is the long-term solution to controlling odors.

The best source of information that I have found, concerning head odors...
http://tinyurl.com/maewwqc

 

[David O]

Wouldn't a flapper valve inhibit air circulation in the tank which in turn would increase the stink factor?

 

[beachbum29]

Wouldn't a flapper valve inhibit air circulation in the tank which in turn would increase the stink factor?

I couldn't see it, but it could be a pressure switch. Whatever it is, it would move when I stuck the nozzle of the cleaner into the fitting.

I have no smell now, but we do pump weekly.

 

[RT Firefly]

Greetings,
+1 what Mr. denverd0n said.

 

[HopCar]

Beachbum, Do you have a Vacuflush system? Peggie Hall told me that some of them used their holding tank as a vacuum tank as well. Those were equipped with a valve in the vent line. The valve was there to let air into the tank when pumping out and to block air from going into the tank when pulling a vacuum on the tank for flushing.
Peggie doesn't think much of the design.

Buy Peggie's Book:
http://shop.sailboatowners.com/prod.php?53615/
I'd tell you to buy it from my website but that's against the rules of this forum.
Who ever you buy it from, just buy it and read it.

 

[beachbum29]

Beachbum, Do you have a Vacuflush system? Peggie Hall told me that some of them used their holding tank as a vacuum tank as well. Those were equipped with a valve in the vent line. The valve was there to let air into the tank when pumping out and to block air from going into the tank when pulling a vacuum on the tank for flushing.
Peggie doesn't think much of the design.

Buy Peggie's Book:
http://shop.sailboatowners.com/prod.php?53615/
I'd tell you to buy it from my website but that's against the rules of this forum.
Who ever you buy it from, just buy it and read it.

Yes, it's a Vacuflush.

I don't think much of this design either but this may be the cure to the system not holding vacuum.

Thanks

 

[Dougcole]

You all are correct, the vent was clogged. I had faulty duckbill valves (which I replaced) I think the Vacuflush system was actually bypassing the outlet DB valves and pressurizing the entire holding tank.

I tried to backflush through the vent line to no effect, so I bent a little hook into the end of a piece of 80 lb test wire leader and scraped around into the vent. Got an instant hiss and a nice odor.

All is working well now, and no more smell.

Thanks for the help.

Doug

 

[FF]

This months Practical Sailor has a easy to construct waste vent filter , with the needed by pass that costs almost nothing to create.