Vacu flush question

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Boatingbill

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I have 2 heads. The system is 1 pump split to 2 tanks. The aft head works fine. The forward has no vacuum at all, as well as foul odor from the holding tank when pump is on. I have removed the toilet itself. Tightened all the hose fittings. As I mentioned the side that runs the aft works fine, so I know the pump is building vacuum. My next guess is the valve. Can anyone tell me how to check it?
 
You have one pump with two accumulator tanks and two toilets.

How are the two tanks and toilets separated so one has vacuum and the other none? Check valves.?

What is the valve you are asking about?

Though it is done often to save money, using one vacuum pump for two toilets is not advised. Too hard to troubleshoot.
 
The manuals include extensive troubleshooting guides. Available on line with a simple web search, just get the one for your model.
 
Thanks for the replies. There is a y between the pump, and the 2 vacuum tanks. They must be isolated somehow as a leak in one would cause both heads to not work. I have it narrowed down to the pressure valve. Just wondering if there was an easy way to check the valve. This is an old boat, but the whole system has been replaced.
 
You said, "as well as foul odor from the holding tank when pump is on."

Do you have odor when either toilet is used or only when you try to flush the malfuntioning one? Is the odor inside the boat or out the vent...or both?

--Peggie
 
Here is a photo with labels of parts of the system. Perhaps this will help you explain the problem to others so we can try to help. Vacu flush diagram.jpg
 
Boatingbill said:
Thanks for the replies. There is a y between the pump, and the 2 vacuum tanks. They must be isolated somehow as a leak in one would cause both heads to not work. I have it narrowed down to the pressure valve. Just wondering if there was an easy way to check the valve. This is an old boat, but the whole system has been replaced.
Click to expand...

If you're referring to the pressure switch, you can pull the stem on the outside out to turn on the pump and push the stem in to shut it off. Do not turn the adjusting knob on the stem, it was set at the factory.

If the pump will not run when you pull the stem, use a multimeter to see if it has 12 v going to it and test switch operation.

The duck Bill's in the two tanks are the check valves to isolate the two toilets in your installation.
 
sum escape said:
Here is a photo with labels of parts of the system. Perhaps this will help you explain the problem to others so we can try to help.View attachment 91787
Click to expand...

OP does not have a vacuum generator like the one pictured in the above post.

I believe he has two accumulator tanks like the picture below and one pump.

OP, is this what you have two of?
 

Attachments

  • vacuum-tank.jpg
    vacuum-tank.jpg
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Last edited:
syjos said:
OP does not have a vacuum generator like the one pictured in the above post.

I believe he has two accumulator tanks like the picture below and one pump.

OP, is this what you have two of?
Click to expand...

Yes. This is my setup.
 
syjos said:
If you're referring to the pressure switch, you can pull the stem on the outside out to turn on the pump and push the stem in to shut it off. Do not turn the adjusting knob on the stem, it was set at the factory.

If the pump will not run when you pull the stem, use a multimeter to see if it has 12 v going to it and test switch operation.

The duck Bill's in the two tanks are the check valves to isolate the two toilets in your installation.
Click to expand...

Thanks. That gives me an idea of what to do. I am usually pretty good at figuring things out, but an understanding of these systems are what I need to learn. This is a 1974 Uniflite 42dc. My first large boat. I was pretty good at things on my old boat, but things are a bit more elaborate on this one! Lol
 
Fwiw, SeaLand didn't decide that it was a bad idea for 2 toilets toilets to use a single vacuum pump until at least the late '90s. I remember thinking at the time that it must have been because they realized they were missing an opportunity to sell two pumps to the same customer. In retrospect, the real reason was because they were about to introduce the combination "vacuum" generator." For the second toilet to use the same pump, a separate vacuum tank would be needed. A lot simpler just to go with completely separate systems.



--Peggie
 
HeadMistress said:
Fwiw, SeaLand didn't decide that it was a bad idea for 2 toilets toilets to use a single vacuum pump until at least the late '90s. I remember thinking at the time that it must have been because they realized they were missing an opportunity to sell two pumps to the same customer. In retrospect, the real reason was because they were about to introduce the combination "vacuum" generator." For the second toilet to use the same pump, a separate vacuum tank would be needed. A lot simpler just to go with completely separate systems.



--Peggie
Click to expand...

I always talked clients from plumbing two VF to one pump. But some boaters are cheap and do that anyway.
 
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