ODay 28 head trouble

[schenckd]

I have a 1981 Oday 28 on freshwater lake. 15 gallon holding tank under V-berth.

The marine toilet bowl refills slowly (from holding tank) after pumping boal dry. This happens with lever on "Wet" and "Dry" settings. Never overflows, just fills about 3/4 full to about (I assume) waterline of boat.

Holding tank about half full.

Would a backflow preventer or check valve help? Any other thoughts, ideas?

Thanks

 

[Ralph Johnstone]

The marine toilet bowl refills slowly (from holding tank) after pumping boal dry.

If it fills from the holding tank (the water is foul) replace the joker valve.

Never overflows, just fills about 3/4 full to about (I assume) waterline of boat.

If it fills from the sea water line (water is clear) clean or replace the vacuum breaker. If there is no vacuum breaker, install an antisiphon loop with a vacuum breaker.

If these terms are unfamiliar to you, check the SEARCH menu near the top of the home page.

 

[Peggie Hall HeadMistress]

Let's apply a little logic...you say your holding tank is only half full, but the bowl is filling from the tank on which the inlet is at the top? If I have that right, tank contents would have to JUMP up to the tank inlet fitting to get into the head discharge hoses to run back to the toilet. Possible? I don't think so.

My guess as to what's REALLY happening: you have a blocked tank vent that's pressurized the system, creating back pressure that's preventing bowl contents from getting to the tank...instead it's pushing it back into the bowl. If you keep flushing against a blocked vent, the pressurized tank could crack, blow out a fitting, or (my personal favorite) erupt in the face of the person pumping the toilet. At the very least, a really unpleasant geyser when you open the deck pumpout fitting. So you need to clear the vent line before you use the toilet again.

The vent thru-hull and the connection to the tank are the most common locations for vent blockage on a sailboat. Start by poking whatever works into the vent thru-hull to clear out whatever might be clogging it...(I wouldn't have my face too close to the thru-hull when you do this if I were you). If that doesn't clear it,you'll need to remove the vent line from the tank...but first VERY CAREFULLY, making sure you're downwind of the pumpout fitting, open the cap to relieve any pressure. Skip this step and you could be cleaning up a really nasty bilge. Then remove the vent line from the tank...scrape out the tank fitting and that end of the vent line.

That should solve your problem. If it doesn't, email me and we'll figure out what will.

 

[Panta Rei]

Let's apply a little logic...you say your holding tank is only half full, but the bowl is filling from the tank on which the inlet is at the top? If I have that right, tank contents would have to JUMP up to the tank inlet fitting to get into the head discharge hoses to run back to the toilet. Possible? I don't think so.

My guess as to what's REALLY happening: you have a blocked tank vent that's pressurized the system, creating back pressure that's preventing bowl contents from getting to the tank...instead it's pushing it back into the bowl. If you keep flushing against a blocked vent, the pressurized tank could crack, blow out a fitting, or (my personal favorite) erupt in the face of the person pumping the toilet. At the very least, a really unpleasant geyser when you open the deck pumpout fitting. So you need to clear the vent line before you use the toilet again.

The vent thru-hull and the connection to the tank are the most common locations for vent blockage on a sailboat. Start by poking whatever works into the vent thru-hull to clear out whatever might be clogging it...(I wouldn't have my face too close to the thru-hull when you do this if I were you). If that doesn't clear it,you'll need to remove the vent line from the tank...but first VERY CAREFULLY, making sure you're downwind of the pumpout fitting, open the cap to relieve any pressure. Skip this step and you could be cleaning up a really nasty bilge. Then remove the vent line from the tank...scrape out the tank fitting and that end of the vent line.

That should solve your problem. If it doesn't, email me and we'll figure out what will.

I read this thinking that we are actually getting some expertise hanging around this forum. Then I noticed it was Peggie. I used her book to design Panta Rhei's two heads, holding tanks and connections . I have never had so much of a drip or a whiff of trouble. Thanks Peggie!

 

[schenckd]

Thanks. I'll give that a try.

 

[Pat]

Peggie, I assume when you say vent thru-hull you mean the small overboard vent that is the tank vent on the outside of the hull.....on our O'Day 272 the vent line runs up to behind and above the hanging locker from the holding tank, to a point where it goes thru the hull to a little black plastic vent on the out-side of our boat...problem is, I think our vent is plugged as well because our head does exactly as described by the first question above....when we take our boat to the pump out station at our club, our holding tank will not pump out the tank until I remove the vent hose so the little vent hose is just sitting on the top of the hanging locker, i.e. venting from air in the boat rather than outside air.....then after the tank is emptied, I re-attach the vent hose...I'll bet our vent is blocked too...I repeat this every month or so when I pump out the head holding tank....I"m not sure how to clean out the vent....it is quite small and the actual opening is very small/ almost like a sliver of an opening...sorry to be so confusing....thank you for your help. Blow it out maybe from inside
Pat

 

[Peggie Hall HeadMistress]

Yep...the tank vent line is what I was meant. If removing that line from the thru-hull allows the tank to be pumped out, that means the blockage is in the thru-hull. If you can't easily scrape it out, you need to replace the vent thru-hull wiith a new one that will allow you to do that. I wouldn't use a "vent" thru-hull...I'd go with an open "bulkhead" thru-hull (see attached photo). That will also allow you to prevent it from becoming blocked because you can stick a hose nozzle up against it and back flush the vent line every time you wash the boat. Yes, spidersCAN crawl into it...dirt daubers WILL build a nest in it...but back flushing will send the spider on a thrill ride into the tank and you can easily scrape out the daubers' nest when you recommission in the spring.

While you're at it, I'd also recommend you relocate the vent thru-hull to a place that'll let you run the vent line in a straight shot directly to it. You can just leave the old one in place if you don't want to mess with patching the hole.

 

[fourwhitesocks]

My 28 Oday head does exactly the same thing.....slowly fills back up about half way, but I have no trouble at all during pump out; does this mean that it's not a clogged vent?

 

[Peggie Hall HeadMistress]

My 28 Oday head does exactly the same thing.....slowly fills back up about half way, but I have no trouble at all during pump out; does this mean that it's not a clogged vent?

Maybe...maybe not. I need more information How long is your head discharge hose? Does it run uphill all the way to the tank? Or, is there a vented loop in the line, which would mean the discharge hose runs straight up to the loop and then over it down to the tank?.

Is there a vented loop in the head intake? Where is it--between the pump and the bowl? Or between the thru-hull and the pump?

 

[schenckd]

Cleared out my tank vent line (clogged at tank connection). Seams to have fixed the problem on mine.