Holding Tank Filling With Minimal Use

[Eras]

Our 25 gallon holding tank is filling within 36-48 hours after being emptied. It will do this at anchor, under sail or sitting at a marina. We are currently at a marina where the head gets used maybe once or twice a day for light business only. The heads are electric. The aft head works fine, the bowl does not fill when the tank is full, but the pressure isn't there to pull a single square of tissue down. The forward head fills when the tank is full. Since there is such light use we are assuming the content filling up the tank is being pulled from outside. Would greatly appreciate some advice.

Regards,
eras

 

[Bill1565]

It's gotta be your thru hull. unless the "poop fairy" is at work. Stuff should not run uphill from your bowls It should have to be pumped uphill,

 

[Bill Roosa]

Electric head you say

I just got corrected by Peggy on another thread about electric heads not having anti siphon valves so I'm going to use my new found knowledge and venture the following.
The thru hull is open, the impeller is allowing fluid past it and it then "drains" into the holding tank.

Try this, close the thru hull and see if it continues. If it stops it would indicate that your impeller is bad and needs looked at. If that does not stop the flow into the holding tank then I'm thinking it is the poop fairies and you need to have a blood sacrifice or something. Peggy would know the correct ritual.

 

[Peggie Hall HeadMistress]

Questions....

How many people are aboard?

Make/model age of the toilet(s)? Do they use sea water or onboard pressurized flush water?

How many tanks? If more than one (there should be on a boat that size), do both fill up, or just one?

Does the tank fill up when no one is aboard?

Does the BOWL fill when no one is aboard?

I'll prob'ly have more questions when I know the answers to these, but this is a start.

 

[Eras]

It's Jabasco 37010-series, 8-15 years old. We bought the boat May of last year and
unsure when/if they've been replaced. They take in sea water.

We have just one tank and two adults on board.

We live aboard so would not know if they'd fill if we weren't here. Highly likely since they both fill at the marina where we use the marina facilities 99% of the time.

Thanks for your help!

 

[Peggie Hall HeadMistress]

I'm pretty sure I know what's happening

If you think it's highly likely that the tank is filling while the boat is sitting in her slip, wouldn't it be logical to close the seacock when you leave to see if that makes a difference? You claim you aren't using the toilet enough for that to create much of a problem, so why don't you try keeping the intake seacock closed except when the toilet is actually in use for a week? Do NOT just pour water into the bowl to flush the toilet when the seacock is closed unless you want to take the entire lower unit apart to replace the intake impeller that's been fried by dry friction heat. You'll have to open the seacock each time to flush the toilet.

If that is the problem--and I suspect it is, you need to install a vented loop with a solenoid valve in the intake for both toilets as shown in the instructions for your toilet here:

http://www.ittflowcontrol.com/files/itemdoc1431.pdf

I suspect you also need to install a tank level monitor to let you know that you need to pump out before the tank overflows. In fact, unless you have easy access to the tank to keep a visual eye one, USCG regs REQUIRE a tank level monitor. I recommend the Profile gauges: Profile Tank Monitors

And I think you also need to replace the joker valves in both toilets AND clean out your tank vent. If the aft toilets still isn't flushing, check for low voltage to the toilet and/or sea water mineral buildup in the head discharge hose.

 

[Ron20324]

My slip-neighbor had what sounds like the same problem. There was a macerator between the holding tank and a thru-hull. That pumped overboard. Being a new owner, he was not aware there was a thru-hull valve that was letting water back INTO the holding tank. Overboard discharge valve closed, problem solved.

 

[Eras]

Thanks everyone for your suggestions. We have a lot of good leads to follow up on. Will post the fix in a few days if we have one.

 

[Guest]

Hunter Passage

Hi Eras, we had a similar experience with our 1991 Passage 42 awhile ago. In our case I had forgotten to close the macerator pump through hull sea cock after legally discharging the holding tank contents. Raw water seeped passed the pump impeller into the holding tank, which is below the waterline.

Another possible cause is if the head anti siphon valve stopped working. In this case if the raw water sea cock was left open after flushing, water will continue to flow through the system and fill up the holding tank to the waterline. I always close all sea cocks when not in use. Just another safety precaution.

Terry Cox

 

[Seattle Scott]

Re: Hunter Passage

Also there should be an anti-syphon loop between the maserator and the thru hull discharge. surprised Peggie didn't mention it. she jumped all over me when I was adding a maserator and moving the discharge thru hull - iI was going to omit the anti syphon since the maserator and thru hull were in the same locker and I was only going to open the thru hull when using the maserator. I put the anti syphon in, but I keep the thru hull closed since over board discharge is rare.

 

[Peggie Hall HeadMistress]

You're jumping to a conclusion, Scott

You're assuming that there is a macerator. All we know is that he's in GA...if he's on Lanier, Allatoona, or the GA side of Lake Hartwell or any other inland lake in GA, it's illegal for boats to have a macerator or any other means of dumping a tank or even any plumbing connected to a thru-hull that would allow a toilet to be flushed directly overboard or a tank to be dumped. If, otoh, he's in coastal waters with immediate access to open ocean beyond the 3 mile limit, there may be one.

Right now, I'm more interested in finding out whether his tank continues to fill up if he closes the intake seacock than I am in whether there's a vented loop in tank discharge plumbing that's prob'ly illegal.

 

[Guest]

Holding tank

Based on the information that Eras provided, Hunter Passage with dual electric heads and a single 25 gallon holding tank, his boat appears to be a P42. Hunter equipped the P42 with a holding tank macerator pump without a vented loop. Awhile back we had quite the thread going regarding the merits or no of such a vented loop. I'm perfectly comfortable with our original configuration and have no plans to add one to the system. Others may disagree.

When we had the boat surveyed at the time of purchase in 2002 the marine surveyor took no issue with the original system nor did the insurance company. Whether there is an ABYC compliance violation, perhaps others can chime in, but our boat has other through hulls without vented loops. Will the boat sink as a result...

Terry Cox