Waste Tank Maintenance

Tips to help your tank (extracted in part from Waypoints Issue 5)

First, just let me say that both the VacuFlush® toilet and the Tank Watch® systems have given excellent service in Nordic Tugs, providing they are properly maintained. THE PROBLEM: Several tug owners called Dan to report that their toilet waste was overflowing into their bilge, and the TANK WATCH indicator lights showed only half full. Luckily, one of the tanks was in a local boat, near the factory, so Dan went out to take a look. The waste tank is located directly under the engine on newer models in a keel compartment. What was happening was that after the tank became full, the pressure of one more flush from the toilet forced the effluent up past the Tank Watch sensor, into the engine pan and on into the mid bilge. But why didn't the Tank Watch indicator panel show the red light that fairly shouts FULL? He found that the Tank Watch sensor, the unit inside the tank that sends Empty, Low, Mid, and Full signals to the Tank Watch panel, was blocked by debris. The debris blocked the float switches from floating up to the contact that sends the LED signals.

The Fix

The Tank Watch sending unit is located in the top of the waste tank, immediately in front of and under the engine. Look for a large ring about 4" in diameter. To clean it; disconnect the electric harness and remove it by unscrewing the probe assembly from the tank top. You may find a flat bar will work to unscrew the probe, bearing against the nubs on the ring. If you do not have a disconnect, it is a good idea to add one (most auto stores have them) as you will likely have to do it again in the future.

Slowly lift the sending unit from the tank and place in a bucket It can then be cleaned by swishing the probes and float switches
around in water. Salt water is okay if you are in a remote area. Mineral deposits can be removed by soaking the probe in vinegar and a gentle scrubbing with an OLD toothbrush. Be careful to keep the electrical components dry and that youdo not damage the probes and float switches. After cleaning, see that the float switches on the bottom of the probes are free to slide up and down. Hook up the wiring to check that you get the green light with the floats all the way down. Replace the probe assembly and tighten. It's a good idea to use silicon grease on the threads to make future removal easier. Hook up the wiring harness.

Preventative Maintenance

When you empty your waste tank, refill at least once it with water and pump it out again. (if your pump-out person is very cooperative, partially fill it again and pump it out.)

Helpful Hints From the Toilet Maker

1. Use rapid-dissolving toilet tissue. Household tissue often contains adhesive, which bond the paper fibers together. It is easy to visualize undissolved tissue fibers wrapped around a tank probe and preventing the float switch movement.
2. Use deodorant when flushing the tank if you want to prevent or minimize the buildup of odors. Hot climates need more
   deodorizing than colder climates. Some deodorants are harsh on the environment; others are more benign, but are less effective as deodorant. Read more about this on the internet – try Sealand Technology.
   
3. Please read the owner's manual – VacuFlush has a good one that's easy to understand with lots of pictures.
4. Consider carrying the appropriate spares for your toilet. Nothing can ruin a cruise quicker than the lack of a toilet!
   

New Technology

We've heard from other owners about a couple of items they added to their waste tank system. The first is a product from Groco. It is called Sweet Tank® and essentially it is a 12v blower which sends a constant flow of air into the tank. This furnishes an oxygen-rich environment, which kills the anaerobic bacteria. It is the anaerobic bacteria that is responsible for the offensive odors emanating from the tank. The second product of interest is a VacuFlush option - an In-Line Vent Filter. This filter is packed with activated filter media (probably charcoal) that removes any odors before they can escape out the hull vent. Replacement cartridges are good for an entire boating season.

Summary

We talk about the engine being the heart of the boat. Maybe it is. But ask any skipper about the time his toilet malfunctioned, with his wife or significant other aboard, and you will witness some pretty strong emotions cross his face. Probably not a memory he'd care to recall. So now that we've reviewed the problems and solutions of holding tanks, you might want to examine your own tank to determine whether it smells clean and the lights for the Tank Watch LED's work properly.

Oh, and keep flushing!