VacuFlush/Waste Tank gurus...

[MV Wanderlust]

The guy across the dock from us has a Sea Ray 340 Sundancer. He told me yesterday that the toilet is no longer flushing. Anyone familiar with the holding tanks on Sundancers?

He's had the boat a while but doesn't seem that knowledgeable about it. He had to describe the system for me to figure out it is definitely a VacuFlush system. He said the holding tank doesn't have an indicator to tell him when the tank is full. He said there is no longer a "whoosh" when he presses down on the flush lever. He does not hear the vacuum pump running at all.

Okay, so it seems pretty obvious there is no vacuum in the chamber. My first thought was that either the vacuum pump isn't working or the vacuum sensor switch is defective. Those are the most obvious places to start, right? There really aren't too many points of failure for those systems.

After thinking about it a little longer... he said he doesn't even remember the last time he had a pump out. If the holding tank is full, could there be some sort of sensor or cut off switch on the holding tank that is designed to shut off the vacuum pump when the tank can't take anymore? Or could there be plenty of vacuum in the chamber but there is a really solid clog in the hose preventing anything from being sucked through? Trying to come up with some additional ideas for him to check.

Thanks for any input.

John

[ValiantV]

Perhaps the simplest and least expensive option is the best place to start.

Maybe he should do a pump out and try again? Seems to me that having a full tank would either making flushing difficult if not Impossible. And if he can't remember when it was done last....

[wingless]

+1, start w/ the pump out.

If the problem remains, then a properly-used plunger could help.

A plunger must only be used on the push stroke. Tip it to the side to not do a suck stroke and potentially invert the duckbill valves. In every case on my boat I've been able to free a clog using this method.

It is possible / likely that the tank level sensors have stopped working properly. On mine, I unscrew / remove / clean / replace the tank sensor assembly to maintain proper operation.

When the holding tank is empty I perform a periodic scrubbing of the tank interior walls. Also the vacuum generator is periodically disassembled / cleaned / inspected / reassembled to ensure the system works properly.

[MV Wanderlust]

Thanks, folks. He is planning to schedule a pump out. I will pass on the additional thoughts. Appreciate it.

[GeneM]

Tanks that sit a long time build bottom sludge that blocks the discharge tube that extends close to the bottom. If the tank is full, it will also block the vent with dried sludge. I bought a boat that had a vent stuffed with black cement.
If a pumpout creates a vacuum, you may have a block.
Raritan CHT in the tank and a trip with some motion should help.

[ranger58sb]

Originally Posted by JohnEasley

He said the holding tank doesn't have an indicator to tell him when the tank is full. He said there is no longer a "whoosh" when he presses down on the flush lever. He does not hear the vacuum pump running at all.

After thinking about it a little longer... he said he doesn't even remember the last time he had a pump out. If the holding tank is full, could there be some sort of sensor or cut off switch on the holding tank that is designed to shut off the vacuum pump when the tank can't take anymore? Or could there be plenty of vacuum in the chamber but there is a really solid clog in the hose preventing anything from being sucked through? Trying to come up with some additional ideas for him to check.

If he hears nothing at all, could be no power to the unit?

But could be vacuum pump failure (I'd guess not first choice) or maybe more likely something like a full tank or clogged vent (symptoms of both are similar), a hard clog in the discharge hose somewhere along the way. A hard clog could be anything from "unflushable items" to scale build-up.

Easiest to troubleshoot one step at a time. Confirm power and water to the unit (breaker?). Pump out, try it. Clean out the vent port, and/or temporarily remove or replace the vent filter (if he has one), try it.

A hard clog is maybe more difficult, depending on hose routing and access and so forth. A test with an air compressor might give some clues, depending on whether that could be applied after the vacuum pump. Blow air into hose, feel for air discharge at the vent outlet.. etc. Or sometimes a shop vac could clear enough of a hard clog to make some progress. Might be able to get a plumber's snake in there...

But I'm not perfectly familiar with the VacuFlush system, so some of that may have to be adapted to fit the situation...

Unless they're brand new, I'd guess also useful to replace the duckbills while at it, if it turns out to be anything other than full tank or clogged vent. Might as well...

I'm told by a dock neighbor that the VacuFlush people provide pretty good phone support...

-Chris

[MV Wanderlust]

Thanks for the input, everyone! I spoke with him last night and it turned out to be nothing more than the holding tank was full. There was a shutoff valve on the holding tank that killed power to the vacuum chamber when the holding tank could take no more. After the pump out, everything started working again.