Changing holding tank vent

D

DeeRow

Member
Joined
Jan 24, 2005
RO Number
16141
Messages
126
My holding tank has a single 1/2" red trace water line for a vent. I am going to install 2 new 1 1/2" vent lines (one on each side of the boat). To do this, should I order the "Holding Tank Installation Kit" or the "Fitting Relocation Kit for Holding Tanks" from BoatFix catalog page 593 http://boatfix.com/catalog/593.pdf

Do I need to use sanitation hose? I'm thinking not since it will only have "fumes" in it. But what kind of hose? page 606, http://boatfix.com/catalog/606.pdf has clear PVC tubing which is 1 1/2" and the description says for holding tank vent. How do you support 1 1/2" clear PVC so that it doesn't collapse?

How do I put a 1 1/2 inch fitting into the tank? Do I need to buy a 1 1/2 NPT thread tap?

So many questions, so little time.
 
You'll need the "Fitting Relocation Kit" which includes a cleanout/inspection cap. The fitting relocation kit includes two 1 1/2" through-hull fittings, which are installed from inside the tank, with the hose barb sticking out (to connect your vent hose(s). The cleanout/inspection fitting will allow you to get your hand and arm inside the tank to install the through-hull fittings. Rubber gaskets, etc., are included with the kit. to plug off your existing vent fitting, you'll need a plastic 1/2" pipe plug from a hardware store or Home Depot. No, you won't need a 1 1/2" pipe tap. The kit comes pretty complete, and if there's anything else you need, you should be abe to get it at a hardware store or a marine distributor.

Where the vent lines will exit the hull, you'll need 1 1/2" through-hull fittings, same as for any other opening you would put in the boat. Those can be gotten here:

http://www.boatfix.com/catalog/660.pdf (lower right - Perko 1 1/2" through-hull fitting)

I'd strongly urge you use sanitation hose, if possible, for the vent line(s). Clear plastic hose is prone to odor permeation, and you won't be happy with it.
 
I used sanitation hose and 2 1 1/2" 90 degree plastic thru hulls. The hole in the hull is almost 4' about the water line. The tank already had an access port so I didn't buy the kit. I installed the new vent in the tank where the old vent was. I was very surprised that the vent line was sticky (it was 3/4" red trace water hose). Also the inside "flange" was a pvc cap with a 3/8" hole drilled in the center. The tank is almost a 1/2" thick. Another interesting find was that the vent thru the hull was not long enough for the hull thickness, so someone ground off the inner hull skin (down to the coring) rather than get a longer vent. Fortunately, the coring was not exposed to water and there was no signs of core rot. I only installed one vent so far but I have purchased parts for the vent on theother side of the hull. I had to disassemble a closet to get access to the hull side.

The single new vent has already improved the smell in the cabin.

Mark
 
You must log in or register to reply here.
Back
Top