Head (vacu-flush) wont flush and Fresh Water systems spurts water

3

340DA

Member
Jul 21, 2008
365
LI Sound
Boat Info
2000 Sundancer Sport Cruiser
Engines
454 Mercruiser w/Bravo III Drives
The head system (vacu-flush) and the Fresh Water system were both working just fine until this past Sunday (5/23/21) afternoon.

When I turn ON the circuit breaker for the head system, the system illuminates on the electric panel in the cabin. Same with the Fresh Water system. They both turn on.

On Sunday afternoon (5/23/21):
Head System: will not flush. I do not hear the pump running. No pressure is building up to enable flushing. The holding tank is empty.

Fresh Water system:
1. is spurting water and then I can hear air coming out of the faucets after a big water spurt comes out. Some water comes out and then it spurts,
2. In the PEX pipes, in the bilge compartment, I can see some air pockets in the pipes and
3. When I turn on the faucet, the fresh water pump will run and it will pump some water, then spurt, then pump less water, etc. The fresh water pump was replaced in 2016
4. When I turn off the faucet, the fresh water pump continues to run but at a very low level. It does not turn off.

I am wondering if the head system malfunction and the fresh water system malfunction are tied together with one another?????
OR, ..... is it just "coincidental" that they both broke simultaneously???

Any help to diagnose these problems is appreciated!!
 
Fresh Water System - Really sounds like the water tank is empty. If that is not the case try connecting a water hose to the city water connection to see if all the plumbing then works normally. If it does then you can concentrate on the pump itself or a blockage of the screen filter before the pump.

Head System - It's a bit strange that both would go out at the same time. Did you have passengers on your boat that might have flushed something down the crapper that should not have gone? I'd try tapping on the pressure switch that should be located on top the tank in a little square box. The cover should just pop off. Next best thing to do is start checking for voltage at the vac pump and the pressure switch.
 
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Have you checked to see if there is a visible blockage in the head? It's not super uncommon to have something plugged in there. Easy to diagnose/repair once you get the water out of the bowl. I've had to use a plunger a couple times though I'm not sure that's the recommended approach for vacuflush :)

Did you run your fresh water tank empty recently? My experience is that it's 5+ minutes of running several faucets wide open to get all of the air out of the system when she goes dry.
 
Response to Little Ducky:
Fresh Water: Boat was commissioned on Friday, 5/21/21. Water tank was filled that day and the first time I really tested it and used was Sunday 5/23/21. I did run the system for several minutes as I tried to diagnose the problem The screen filter on the pump is clear

Head: nothing was flushed down the toilet to block it (to the best of my knowledge) because my wife and I were the only ones to use the toilet.
I can try to locate and check the pressure switch

Response to: Stee6043
Head: can you tell me how to check for blockage?

Fresh Water: tank was empty for the winter until it was filled on 5/21/21..... It ran fine from 5/21 until 5/23/21... Filter is not clogged and it is only half filling with water. Pump runs but wont stop.... I hear air spurting out.... I dont see any obvious/visible leaks from the pipes...
 
340DA said:
Response to Little Ducky:
Fresh Water: Boat was commissioned on Friday, 5/21/21. Water tank was filled that day and the first time I really tested it and used was Sunday 5/23/21. I did run the system for several minutes as I tried to diagnose the problem The screen filter on the pump is clear

Head: nothing was flushed down the toilet to block it (to the best of my knowledge) because my wife and I were the only ones to use the toilet.
I can try to locate and check the pressure switch

Response to: Stee6043
Head: can you tell me how to check for blockage?

Fresh Water: tank was empty for the winter until it was filled on 5/21/21..... It ran fine from 5/21 until 5/23/21... Filter is not clogged and it is only half filling with water. Pump runs but wont stop.... I hear air spurting out.... I dont see any obvious/visible leaks from the pipes...
Click to expand...

I've twice had plugged heads where I could see the blockage. Turn off the water, stand on the flush pedal (to open it up) and inspect. You may be able to see some TP or something else blocking the smallish orifice at the bottom. You can either pull it out (likely preferred) or force it through.

I think it's okay to see some air inside your strainer. I replaced my strainer over winter and still have a little air in there. If you flip the strainer over I'd bet the bubble will be gone. Have you tried running several of your faucets open all at the same time for several minutes? Do you know whether or not your hot water heater has filled up?
 
Head: there is a blockage if the breaker is on and working. You need to clean it out, most likely TP effecting duck bills or the pump or both.
Water. If the system was empty because you had the fresh water switch on while attached to shore water...the boat will pull water from pump/tank. If that runs dry, then when you add water it will have air in the lines. Open all valves and if water trickles out, go to the pump and crack the line just after the pump. This should then blow fresh water everywhere, but then as it's doing so, attach the pen back up and you should start to build pressure. You might still have some air, but pressure will be better.
 
I appreciate all the advice...... THANKS

HEAD: I understand the suggestion that there may be something stuck in there. However, even if something is stuck, the vacu-flush pump is still not kicking on. Thus, no vacuum is being created......... Maybe it's designed that way??? to not turn on if there's a blockage?
I can check for a blockage but even if there is, I would think that the pump should kick on anyway? (maybe I'm wrong)
I'm beginning to think the issue is at the pump.... it's the original pump (2000 340 Sundancer)

WATER: The way that the water spurts out of the faucets, and the sound of forced air that I can hear from the faucet, makes me think that there's a crack/break somewhere in the system. I'm thinking the system is compromised somewhere and it is not sealed....... thus allowing air to get in and preventing pressure from building???? However, I do NOT see any leaks along where the PEX pipe is visible in the bilge, or just below the faucets.... A crack could be somewhere else along the system where I can't see......... but if that's true, then I should see some water spots where the crack/break is????
Does that Make sense????
 
@340DA When the Freshwater pump is running (and you mentioned that it won't shut off) go to the discharge side of the pump and loosen the outlet fitting. You don't have to take it off, but loosen it sufficiently so that any air at the pump can escape. You will know you've done good when water spews out of the loosened fitting.

Jaybeaux
 
Water: Look back at some of the responses... you missed the part about whether or not the hot water heater is fully filled. If not, you'll get spurts until it does. If that's not the issue, then look between the tank and the pump (not after the pump). That would cause the same issue - air being sucked in. This could also be the tank pick-up tube, itself. If you fill the tank completely, and the issue goes away, the culrpit is the pickup tube. Were any parts of the system taken apart for winterizing? If so, check and reinsert fully.

Head: Yes, you're mistaken on the theory of why the pump won't turn on if there's a blockage. A blockage will trick the vacuum pump into thinking proper vaccuum has been reached and it won't turn on. As far as it is concerned, vaccum HAS been created (which it has... between the blockage and the vac pump/tank). Check (play with) the vac switch, as well - could be faulty. Also could be faulty motor.
 
Jaybeaux: Thanks for the response and suggestion.

Lazy Daze:
FRESH WATER: Thanks for the reminder. The Hot Water tank is disconnected and has been for several years. The fresh water system bypasses this tank completely.
Therefore, I'm also thinking that this issue is between the fresh water tank location and the pump (as you indicated, "before" the pump). The water pipe goes from the tank, thru the bulkhead, and to the motor located in the bilge compartment.
So, yo are suggesting it could potentially be:
1. The pick up tube located inside the Fresh Water tank?
OR
2. somewhere in The PEX tube between the FW tank to the pump?

HEAD:
1. where is the Vac switch located?
2. Is there a way to determine if the motor is faulty?

Make sense?
 
OK, so the HWH is a non-issue - that helps things.

Yes, if you're getting air in, the most logical places to look are going to the pickup tube, the connection at the the top of the tank for the tube, the line to the pump or the pump, itself. Directly before your pump (basically attached to it) is going to be a cleanable filter. Check that, too. These are also a common place for items to be disconnected during winterizing and possibly not inserted fully back in. While possible, it's much less likely that a pex line, itself, is the issue. I'd start at the pump connections/filter.

The vac switch is mounted on the vac tank - it's the springy thing. Power to the motor but the motor doesn't run is the way to check.
 
Thanks Lazy Daze..... I'll keep you posted....
 
To rule out/bypass some things. I once had a fresh water pressure issue, and also thought I had a leak, it did not show itself when on dock water.
 
mrsrobinson said:
To rule out/bypass some things. I once had a fresh water pressure issue, and also thought I had a leak, it did not show itself when on dock water.
Click to expand...
What was the problem? and what did you do to fix it?
 
Mine turned out to be a leak in a line going to the hot water tank. The pump could not hold pressure. At the same time I used an air compressor to blow out the line coming out of the water pump, like you are winterizing. There must have been some trash somewhere as doing that improved the water flow.

I had a separate issue where I found a lot of water in the aft storage compartment. I ended up replacing the dock water connection to resolve that one.
 
mrsrobinson said:
Correct, so this test would rule out anything after the water pump. Correct?
Click to expand...
Correct.

As a side note... the pump acts as a one way valve, which is why dock water won't go into the tank.
 
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