Holding Tank Vent Loop Clogged

Fresh/Waste Water Systems, Watermakers, HVAC, Refrigeration...
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GeoffSchultz
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Holding Tank Vent Loop Clogged

Post by GeoffSchultz »

One of my least favorite jobs has to be anything that deals with the waste system. This summer when we were in some anchorage and the tank needed to be pumped. I was getting ready for the pumpout boat to arrive, so I took off the deck fitting and as soon as it cleared the threads, a geyser of sewage erupted! Does anyone remember Chevy Chase in Vacation? :o To say that this was unpleasant would be an understatement. Sue wasn't happy and I didn't make friends with the pumpout driver.

Clearly something was clogging the vent line and caused the tank to pressurize. Yesterday I undertook the lovely job of determining where the problem was. As I quickly found out, the vent line attached to a fitting which was located underneath of the hot water heater. Lovely...so I had to pull the hot water heater, which means disconnecting the engine coolant loop, the cold feed and hot return, the 120V feeds and the screws holding it in. Believe me, I'm not a small guy and I have to compress myself between the top of the tank and the deck to reach the fittings. However, I've done this many times before, so I knew the drill and within 30 minutes it was out.

Then I discovered that the thru-hull fitting is located directly behind the junction where a bazillion wires go through a bulkhead. Getting there was next to impossible. Wonderful! So, I decided to cut the hose where I could access it and see if I could see the source of the clog. What I did find was what looked like pine needles filling the vent line. I'm no expert on s%*t, but this didn't look like fecal matter. I attached a hose to it and blew it out with water and based upon what I saw on the dock, I think that it was plant matter probably deposited by some bug. Thus a work item: Place a screen over thru-hull vent so that bugs can't get in.

Then I checked out the tank fitting. The first thing that I found was that welded aluminum elbow on the tank was cracked just below where the hose attached. That snapped off when I tried to remove the hose. With the hose off, I discovered that the interior of the elbow was completely clogged with what looked like aluminum corrosion as it was white and powdery. I was able to ream that out and the rest of the metal on the elbow seemed structurally sound, so I attached a new piece of hose to it and used a union to join the 2 sections of hose. Of course this makes me very worried about what's going on inside of the tank...

So, the moral of the story is don't let your holding tank vent line to get plugged and if it does, be careful, very careful when opening the deck fitting!

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

Skipper Skip
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Joined: Sun Dec 14, 2008 12:27 am

Re: Holding Tank Vent Loop Clogged

Post by Skipper Skip »

Geoff,

Tell me and tell me true! ARE WE HAVING FUN YET???????? :roll: :lol:

Skip

There are those Going Somewhere and those Going Nowhere!
Where Are You Going?


1982 F33CK, Shoal Keel
Southern CA

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GeoffSchultz
Posts: 1135
Joined: Thu Dec 04, 2008 8:39 am
Location: BlueJacket: Guatemala
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Re: Holding Tank Vent Loop Clogged

Post by GeoffSchultz »

Skipper Skip wrote:Geoff, Tell me and tell me true! ARE WE HAVING FUN YET???????? :roll: :lol:
Of course not, but a beautiful day of sailing puts all of those memories well behind me and makes it all worth while.

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

Skipper Skip
Posts: 4
Joined: Sun Dec 14, 2008 12:27 am

Re: Holding Tank Vent Loop Clogged

Post by Skipper Skip »

Yup :D And the Ladies wonder why we refer to the boat as “SHE”! ;) :lol:

Skip
"There are those going Somewhere and those going Nowhere!" Which are YOU?

1982 F33 CK, Fixed Shoal Keel
Southern CA.

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