Do I need a Vented Loop?

[Chuck978]

Hi Peggy,I purchased a "new to me" 33'Cal and ripped out the entire head system and replaced it with new hoses, new elec. head, holding tank, and elec. overboard discharge pump. The outlet from the holding tank goes to the diverter valve where one side of that goes to the deck pumpout fitting and the other side goes to the elec. dicharge pump. After the pump, which sits at about the waterline, the hose goes upward above the waterline and then down to the throughhull, well below the waterline. The pump has two duckbill valves in it. The head also has another duckbill valve. Do I need a vented loop between the discharge pump and the throughhull?P.S. I replaced the old hose with the Shields hose and then saw your recommendation to use the SeaLand Odorsafe hose, so I did that too. That stuff is a bit of a wrestling match to put in.Thanks Much,Chuck

 

[Peggie Hall HeadMistress]

Technically, yes...but...

"After the pump, which sits at about the waterline, the hose goes upward above the waterline and then down to the throughhull, well below the waterline."ABYC safety standards call for a vented loop 8-12" above the waterline at any angle of heel...but if the loop you put in the hose is that high, you're prob'ly ok. However it's essential that you keep that seacock closed at ALL times except when actually dumping the tank...'cuz even a vented loop won't prevent water from being forced up the hose and flodding the tank while underway and the duckbills in the pump won't block it, only slow it down.

 

[Chuck]

Thanks for the help!

Thanks for your response!It's nice to be able to get a little professional advice now and then. Your the best.Chuck