Sanitation discharge vented loop issue

[sailorick424]

I have a Raritan Marine Elegance electric head with a LectraSan system that goes to a Forespar vented loop. When the head discharge pump is working, stinky air and sometimes liquid escapes the Forespar vented loop duckbill. My Admiral finds this totally unacceptable. Cleaning and replacing the duckbill has not solved the problem. Forespar and Raritan techs do not have an explanation. Thinking that there might be a pressure build up due to blockage in the hoses, I removed all of the sanitation hoses and discovered they were not obstructed. I have read and re-read my Peggy Hall, Nigel Calder and Don Casey books looking for a possible explanation/remedy but did not see anything.
I’m wondering if I should buy a Groco vented loop as it’s vent is not at the top of the loop but rather off set above the downward leg of the loop and might not experience the pressure the duckbill on the Forespar experiences. What else can I try?

[peghall]

If your vented loop is PVC with a threaded nipple on top into which the air valve goes, I'd try replacing the entire air valve, not just the duckbill. 'Cuz the air valve should only open to allow air into a line through which water is being PULLED...water being pushed through a line shouldn't squirt water OR air. Any air valve designed to thread into that nipple should fit.


--Peggie

[BilgeRat]

What Peggie said, plus—- first take out the duckbill. It should be facing inward with the bill. Inspect the bill. It should be closed 100% when clean. If not, replace it.

If that doesn’t do the trick then you have a bigger problem. There should be absolutely NO leaks in the discharge lines ANYWHERE.

There should never be any leaking from the vent valve.

BTW in assembling the hose you can dip them in hot water to soften them AND you can use KY jelly for installation inside the hose and on the nipple. I keep KY on board for engine hoses too.

[sailorick424]

peghall and BilgeRat...
Thanks for the info, sorry for not getting back sooner...
As I plan to reduce my hose size from 1.5" to 1", I'll need to purchase a new loop with vent... I won't get another Forespar. Which loop/vent would you recommend - Groco, Vetus, Buck Algonquin, Scot or something different?
Thanks again

[peghall]

What do you have against getting another Forespar? A vented loop is just PVC pipe bent 180 degrees with a nipple on the top into which an air valve is threaded. Unless you want to spend the money for bronze....???


--Peggie

[sailorick424]

peghall...
The forespar valve I have now will leak air and liquid when the discharge pump is run. Replacing the duckbill did not solve the problem...
looking for any reliable way to eliminate the odors this causes...
Thanks

[BillKny]

Are you 110% SURE that you have the duckbill valve facing the right way? The “duck’s bill” faces DOWN into the pipe.

You have a leak through, or around the duckbill valve. That is the whole cause of this. If you have installed a new one, the chances of it leaking through are very small. I have seen people damage the seat by carelessly digging out a duckbill valve with a screwdriver, so that’s possible, too.

[sailorick424]

BillKny
Thanks
Yes, I'm certain the duckbill is installed correctly.
Neither cleaning the existing duckbill nor replacing the duckbill with a new one solved the problem.
I don't recall having to use any implement when removing the duckbill.

[Uncle Bob]

I recently encountered the reverse problem with the duckbill, a small amount of crud had rendered it inoperable and the toilet slowly filled with water, a simple cleaning of the valve and re installation solved the problem, however it is very easy to reverse the valve, producing the results you describe.

[gonesail]

I hate those things. I have one in my cockpit locker for the overboard discharge. You guessed it .. it stinks. But hope someday to fix it