Seepage from Waste Line Vented Loop...

[JoyRide28]

Hi Peggy, et., al., Happy New Year. I have what I hope is a fairly simple question. I have noticed that there is a little seepage of sewage which bubbles from the top of the vented loop located between the head and the holding tank. It's both stinky and annoying, although it is a very small amount of liquid. My question then is: Is this normal? And further, if not normal, how do you recommend fixing it? Obviously replacing the part is easy, if that's the answer. Thanks in advance! Peter

 

[Lee Coller]

Why do you have a vented loop between the head and the holding tank? That should be a straight run (ideally all downhill). The vented loop should be on the intake after the pump.

 

[Peggie Hall HeadMistress]

Yes, there should be a vented loop in the intake, but it's not a matter of "THE vented loop"...there can be a number of reasons for another one in the discharge line. In fact, if there's a y-valve that provides the option to discharge the toilet directly overboard when at sea beyond the "3 mile limit," a vented loop in the discharge line is REQUIRED.

Whether the loop is in the intake OR the discharge, there should be an air valve in the nipple on the top of the loop that only allows air INTO the line to break a siphon...nothing out. Either yours is missing or it needs cleaning or replacement. That should solve the problem. Do NOT put a vent line on it! The line would have be so small--only 1/4" ID--that it will very quickly become clogged by waste and/or sea water minerals, turning the loop into an UNvented loop that no longer has any ability to break a siphon...and because it's solved the problem--squirting--it becomes "out of sight, out of mind"...never cleaned.

 

[JoyRide28]

Thanks Peggy. It's a 17 year old boat. I suspect this is the original part. I will order a replacement. P

 

[Peggie Hall HeadMistress]

You don't need a new vented loop....the air valve is a replaceable part. On a PVC loop, it threads into the hole in the nipple at the top of the loop. If yours is a bronze loop with what looks like a cap, contact Groco...either they made it or W-C did, but W-C no longer exists, so Groco would be the source for any repair parts.

 

[JoyRide28]

OK. Thanks!