Holding Tank Woes

[jmagel]

In the 3 months we've owned the boat, I haven't ever seen the 3/4 full light trigger, which leads me to believe it's not working. For some reason, I thought the vaccuflush systems shutoff when the tank is full, but last weekend I looked in the bilge one bulkhead forward of the holding tank and found the indication of sewage (90% sure, but didn't fully check yet -- had guests on board and didn't want to freak them out). Going back this weekend with a shop vac + some bleach to take care of it.

I'm just a little perplexed as to where it came from. The top of the holding tank is clean as a whistle. in fact the compartment surrounding the holding tank is the cleanest, whitest space on the boat. Also, no odor escaping from the tank. Emptying the tank on deck works great, so seems like the vent is working well enough. Did it come from overfilling the tank? If so where did it escape? How did it end up in the adjacent compartment (separated by a bulkhead)? Could the vent line have ruptured in that area. I haven't traced it's route yet, but it could definitely traverse that compartment.

After I clean up the bilge, I'll keep a close eye to see if/when it happens again. Any thoughts?

 

[Angela]

If your tank was full and the toilet was still be used and flushed, the waste could have been going out the vent. How old is the vent hose and what condition is it in? Could there be a small crack in the vent hose where the sewage could have leaked out, or perhaps a broken or loose hose clamp holding it on? Where was the waste in the bilge in relation to where the vent hose runs? Just some ideas. Vacuflush does not automatically shut off when a tank is full, unless this is some new model of Vacuflush that wires into your holding tank sensor. I've never seen one triggered like that, not to say that someone hasn't done it.

By the way, it was over 6 years before I ever saw my 3/4 full light come on. I never let it get that full, I suppose.

 

[jmagel]

If your tank was full and the toilet was still be used and flushed, the waste could have been going out the vent. How old is the vent hose and what condition is it in? Could there be a small crack in the vent hose where the sewage could have leaked out, or perhaps a broken or loose hose clamp holding it on? Where was the waste in the bilge in relation to where the vent hose runs? Just some ideas. Vacuflush does not automatically shut off when a tank is full, unless this is some new model of Vacuflush that wires into your holding tank sensor. I've never seen one triggered like that, not to say that someone hasn't done it.

By the way, it was over 6 years before I ever saw my 3/4 full light come on. I never let it get that full, I suppose.

This is helpful, thank you! This boat is new to me, so I can't say for certain the age of the vent hose. There's a good chance it's original (all the plumbing appears to be) so possibly 18 years old. I'm thinking it must be a hose because of the location. I haven't traced the hoses yet -- couldn't get a great look last weekend -- but this will be my first inspection when I get back in there with some light.

My newer boats have had the auto shutoff on the pumps, but it must not be a feature in the older systems.

Hoping it's a hose and not a cracked tank!

 

[Pascal]

Usually leaks with a full tank come from the fittings at the top, especially the gauge fitting.

In yr case if the top of the tank mid its immediate surrounding is clean then it s something else.

Do you have an onboard pump/macerated, maybe in that compartments forward of the tank where ou found the waste? There could be a leak in the plumbing. It may also have a vented loop which obviously should be higher than the top of the tank, but you never know...

Also, check to see if if you have a charcoal filter on the vent line. Many boats do. If the tank is full the charcoal will get wet an clog the vent permanently leadin got all sort of problems. These filters are about 10" long cylinder, about 4" diam

Personally I don't like those filters, unless the vent is close to an open hatch, cockpit, etc.

 

[captainwjm]

I agree w/ Pascal's comments. I don't use a filter either.

 

[magnawake]

Seems like you could test the switch by pressing in on the diaphram and activating the light. My switch rusted into pieces so its not currently installed. I installed another type switch and after I installed it, I found that my light bulb was burned out. Maybe when you pump out, you can rinse with fresh water and fill the tank up to 3/4 and test the warning system. I just like testing things. It gives me a warm fuzzy feeling.

 

[jmagel]

Thanks for the additional leads. I checked all hoses and connections today and I couldn't find any source of failure. I couldn't even find a trace of the source (like a stained wall). We also don't have a macerator, vented loop or a charcoal filter.

So went ahead and started the dirty work and as I got a closer look, we realized the debris that looked like toilet tissue was actually strips of bilge paint! The brown stains also seemed to be just bilge gunk.

So turns out this might have been a false alarm. I think we are getting a little odor permiation from the vent line in that compartment. And that coulpled with the visual of a foul bilge led me to think the worst. Still keeping an eye on it, but I think we're ok. Now I just need to test that 3/4 light and find out for certain if its shot.

Thanks for all the help!

 

[Maynard Rupp]

You need to locate and service your sensor switch. From the top of your holding tank, follow the small black plastic tube. That tube will end at a red thing that looks like a hockey puck. The cover is soft and easily pulled off. Inside is an aneroid that expands as the holding tank fills. That operates an arm that actuates a small switch. that switch completes the ground to your holding tank 3/4 full bulb. On most of our old boats the brass tube inside the tank has rotted off some and our light comes on when the tank is almost full. The steel arm that operates the switch corrodes but usually can be freed up to rock correctly and actuate the switch. Your bulb should have voltage on one wire and the other will ground when the little switch is tripped. Sams has the hockey puck and the replacement brass tube. On our boat it would be almost impossible to remove the tube assembly from the top of our tank.

 

[magnawake]

You need to locate and service your sensor switch. From the top of your holding tank, follow the small black plastic tube. That tube will end at a red thing that looks like a hockey puck. The cover is soft and easily pulled off. Inside is an aneroid that expands as the holding tank fills. That operates an arm that actuates a small switch. that switch completes the ground to your holding tank 3/4 full bulb. On most of our old boats the brass tube inside the tank has rotted off some and our light comes on when the tank is almost full. The steel arm that operates the switch corrodes but usually can be freed up to rock correctly and actuate the switch. Your bulb should have voltage on one wire and the other will ground when the little switch is tripped. Sams has the hockey puck and the replacement brass tube. On our boat it would be almost impossible to remove the tube assembly from the top of our tank.

A hard time removing the tube? Nawww say it aint so. I cant get mine out either. We ran a camera down into the fill elbow and my tube is gone. I just cut it off and capped it for now. I'm in a bind and dont have the time to mess with it. So anyway, howd you finally get it out? I was thinking a saws all might do it.

 

[Maynard Rupp]

I didn't get it out. I use my indicator light as a "tank almost full" indicator. The whole system will work fine, it just doesn't give you much warning. When the aneroid expands it makes the switch which completes the ground path and on comes the light. It just comes on at lower level with a good tube.

 

[MikeP]

FWIW, if you are going to re-do the tube, you can make it whatever length you want to make it illuminate at whatever level you like. When I redid ours I thought about changing the level but decided that Hatt had a pretty good idea with 3/4 full. Since there are only two of us on the boat 90% of time - having an additional 1/4 tank when the light comes on is plenty of "advance notice." But if you had more people on board using the facilities regularly, maybe 2/3 full would be a better option.

Obviously a real gauge would be more useful but we have found the oem system to work fine for us.

 

[jmagel]

You need to locate and service your sensor switch. From the top of your holding tank, follow the small black plastic tube. That tube will end at a red thing that looks like a hockey puck. The cover is soft and easily pulled off. Inside is an aneroid that expands as the holding tank fills. That operates an arm that actuates a small switch. that switch completes the ground to your holding tank 3/4 full bulb. On most of our old boats the brass tube inside the tank has rotted off some and our light comes on when the tank is almost full. The steel arm that operates the switch corrodes but usually can be freed up to rock correctly and actuate the switch. Your bulb should have voltage on one wire and the other will ground when the little switch is tripped. Sams has the hockey puck and the replacement brass tube. On our boat it would be almost impossible to remove the tube assembly from the top of our tank.

Thanks for the info here. I was able to find the "hockey puck" and activate the switch by hand to test the lights -- all good there. Here's a photo of the switch with an empty tank. Will I be able to see the gap close as the tank fills (assuming its working properly)?

 

[MikeP]

I never had mine open like that so I don't know if you can see the movement but you can hear it "click" when it activates. Or you could disconnect the existing wires and attach a multi-meter to the terminals. Set it to "beep" for continuity if that feature is available on the particular meter or just set for resistance and watch for the reading to go to continuity if the meter doesn't have a beep feature.

 

[Maynard Rupp]

As long as the aneroid doesn't have a leak, and your switch lever is free to move, it should work. I never watched my aneroid expand but you could. If you get the electrical part correct and the bulb is good, it will work. The only question is, at what level will your light come on? Heck, fill the tank with water having someone watch the bulb. When the bulb lights see how much more water it will hold before it runs out the vent.

 

[Beckytek]

You can also adjust those screws on the springs to make contact sooner or later than 3/4 full.

 

[MikeP]

"screws on the springs to make contact sooner or later than 3/4 full."

Good Info - a lot easier than cutting pipe to adjust it!