Clogged holding tank vent

[HeadMistress]

About the only "vent" fitting your going to find is a fuel tank vent. Has screens to keep bugs out, and as a spark arrestor for gasoline. You absolutely don't need or want a screen on a holding tank vent. A regular mushroom type through hull is much better, won't clog as easily and you can clear it with a shot from a water hose.

AMEN!

And with an open bulkhead or "mushroom" thru-hull you shouldn't need a garden hose connection or any other contraption to clear a clogged vent because you won't ever have a clogged vent again if you just remember to put a hose nozzle against the thru-hull to back flush the vent line every time you wash the boatand/or pump out. Anything that's trying to set up housekeeping in it just gets a water slide ride into the tank.

I just re-read the last two pages of this thread...this only the 4th time I've posted this.



--Peggie

 

[tcoop]

Ok, so after declaring victory last week and about 6 flushes later the smell is back after flushing. All flushes are liquid, the system hasn't seen solids for 3 years. The only thing I tried yesterday was to flush the vent with the water hose. One of the reactions has me puzzled.

Removed pump-out cap before starting. If I did a few seconds of applying water into the through hull as soon as I stopped water would run out. I assume this is due to the anti-syphon hose routing. But when I ran the water for an extended time I got the initial water and then a second later more water would come out like it was pressurized. Is this from creating a syphon?


Last week when I had the vent hose off I used a 12 inch screwdriver into the tank fitting and moved it around to ensure that there was no blockage at that junction. The tank is part of the keel but I though 12 inches would have been plenty past the hose connector. Wrong assumption?

 

[HeadMistress]

Sounds like your tank IS pressurized....Did you try scraping out the vent thru-hull?

Btw...is your odor inside the boat or out the tank vent? is there a filter in the vent line?


This may need more detailed discussion than is practical in a forum...You're welcome to move it to a PM from which we can move it to email so we can swap some attachments


--Peggie

 

[tcoop]

Thanks Peggie, I did push a plastic rod into the 1/4 inch hole in the thru- hull and a wire that I got in about 6 inches. The thru-hull is a right angle pointing at 12 o'clock.

The odor is inside closer to the saloon with the one VF head forward. No filter in the vent.

I would be happy to or email. I will PM my email.

 

[Comodave]

Are you sure there is no filter. On our boat Formula hid it very well. Almost impossible to see much less change.

 

[tcoop]

At this point I am not sure of much but I don't think there is a vent. I had the hose completely removed last week. it connected to a plastic fitting that is glassed into the keel and the other end was at the thru-hull. The hose is less than 8 feet.

 

[Comodave]

If you had the hose out completely then you should have been able to tell if it was blocked. If you rule out the hose then the clog must be either the fitting at the tank or the through hull. Not much else it could be in the vent part of the system. Good luck.

 

[Bmarler]

Ok, so after declaring victory last week and about 6 flushes later the smell is back after flushing. All flushes are liquid, the system hasn't seen solids for 3 years. The only thing I tried yesterday was to flush the vent with the water hose. One of the reactions has me puzzled.

Removed pump-out cap before starting. If I did a few seconds of applying water into the through hull as soon as I stopped water would run out. I assume this is due to the anti-syphon hose routing. But when I ran the water for an extended time I got the initial water and then a second later more water would come out like it was pressurized. Is this from creating a syphon?


Last week when I had the vent hose off I used a 12 inch screwdriver into the tank fitting and moved it around to ensure that there was no blockage at that junction. The tank is part of the keel but I though 12 inches would have been plenty past the hose connector. Wrong assumption?

are you saying the vent hose fitting points up in the inside of the hull, and has an anti-siphon fitting on it? after that it heads down to the tank?
if so, isn't the anti-siphon essentially venting inside the boat?
i thought the vent line was to be an unobstructed straight line to the tank.

 

[tcoop]

No, the fitting is 90 degree and pointing straight up. The hose connects making an arch before heading down to the tank. I was using anti-syphon to describe the arch in the hose. There is no true anti-syphon valve just the hose arch.

 

[SteveK]

Sounds like your tank IS pressurized....Did you try scraping out the vent thru-hull?

Btw...is your odor inside the boat or out the tank vent? is there a filter in the vent line?


This may need more detailed discussion than is practical in a forum...You're welcome to move it to a PM from which we can move it to email so we can swap some attachments


--Peggie

Peggie, are these attachments to large to attach here?
They may be helpful in advance for many.
I had a pressurized tank and had read your post on inline filters, which I removed and did not replace. Your advice is valued and I do not want to miss any.