Mansfield Vacuflush

I have a Mansfield vacuflush system on my Gulfstar 44. My vacuum pump runs almost all the time. Sometimes it does shut off but not for more than 5 minutes. 1 pump for both aft and foward heads. I have cleaned the tubing twice and seems to work pretty good for about 2-3 days but the cycle time gets less and less. I cannot find any leaks. If the system is good, how often should the pump cycle on and off?

saltysailor said:

I have a Mansfield vacuflush system on my Gulfstar 44. My vacuum pump runs almost all the time. Sometimes it does shut off but not for more than 5 minutes. 1 pump for both aft and foward heads. I have cleaned the tubing twice and seems to work pretty good for about 2-3 days but the cycle time gets less and less. I cannot find any leaks. If the system is good, how often should the pump cycle on and off?

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Welcome, have you cleaned the seals at the bottom of the bowls? There is a special tool, something resembling a fingernail file, for the purpose.

saltysailor said:

I have a Mansfield vacuflush system on my Gulfstar 44. My vacuum pump runs almost all the time. Sometimes it does shut off but not for more than 5 minutes. 1 pump for both aft and foward heads. I have cleaned the tubing twice and seems to work pretty good for about 2-3 days but the cycle time gets less and less. I cannot find any leaks. If the system is good, how often should the pump cycle on and off?

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Never.. unless there is a leak or a bad flapper or a bad pressure switch.

I leave the boat sometimes for weeks with the power off to the head and it keeps vacuum.. turning on the power ant the thing still doesn't activate until flushed

HOLLYWOOD

Most likely cause is a failed sensor in the vacuum tank switch...it's at the end of the vacuum tank).

The vacuum tank switch has a sensor that that turns the pump on when the vacuum drops--as in flushing the toilet...turns it off when the right amount of negative pressure (vacuum) has been reached. It has a lifespan of 2-5 years. Unfortunately you can't order just the sensor, you have to replace the whole vacuum switch..it's an easy swap out, though. You can order a new one from SeaLand...800-321-9886.

Btw...Mansfield Plumbing spun off their marine toilet division to SeaLand Technology in 1984...they're now owned by Dometic, a European company. The VacuFlush has changed so little except for cosmetics since Mansfield introduced it in the late '70s that the trouble shooting guide in the owners manuals for any year/model is the same. Sounds like all of you who chimed in need one. I've saved it as a PDF that I'll be glad to attach to a reply if you'd like to email me. peggie(dot)hall(at)gmail(dot)com.

I disagree. The first suspects are the duckbill valves in the pump. When were they last changed?

caltexflanc said:

I disagree. The first suspects are the duckbill valves in the pump. When were they last changed?

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What he said

The duckbills were changed about 3 weeks ago. I have broken almost every joint on the hoses. I have read not to use any sealant on the joints but double hose clamp them. Is this correct? Maybe the vacuum switch for the after tank may be bad since that is where I have had the most problems. That is the last thing I haven't changed. Also I found a lot of scale in the hoses. Is there something I can use to reduce the scale buildup?

Thanks for all the responses.

caltexflanc said:

I disagree. The first suspects are the duckbill valves in the pump. When were they last changed?

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I didn't say it was the FIRST thing to check...I said that (in this case) it's the most likely source of the problem. There's a difference.

Leaking duckbills will cause a pump to cycle, first briefly and further apart, then longer and more frequently. They would not cause the pump to run continuously....that's most likely caused by a failed vacuum tank sensor. Early, the pump starts running longer...then longer and longer...till finally it won't shut off at all...which is about where it is on his boat.

mansfield head keeps cycling

I've completely rebuilt several vacuum toilets ,pumps , tanks. There are several places that can leak but I have found that the toilet ball to seal is the biggest culprit. If it's been in a long time, change it. It's a very simple fix and don't let it scare you. Environmental Marine is a great source for help and parts. They are in Lauderdale and can get you everything. You can try holding pedal down and gently turning a cleaning brush in the hole while water runs. If that effects the cycle time then it probably is the ball seal.

It's obvious when the toilet bowl seal is the problem...you can hear it.

mike66 said:

It's obvious when the toilet bowl seal is the problem...you can hear it.

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Yep true statement!!!!

I was responding to the post before mine.

Kind of relevant-This is in regards to a vacuum pump running for whatever reason. I had quests aboard that didn't flush properly and the vacuum pump ran continuously. I was at the helm and didn't hear the pump running, which ended up burning out. The replacement was $250. I added an in-line 12v timer that you can adjust the run time. I think it cost around $15. Best peace of mind I ever bought.
P.S. Don't be on a boat with five other dudes with the only toilet broken!

Mac2 said:

...
P.S. Don't be on a boat with five other dudes with the only toilet broken!

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BTDTUTLGB.

Been There Done That Used The Little Gray Bucket.



Later,
Dan

Mac2 said:

Kind of relevant-This is in regards to a vacuum pump running for whatever reason. I had quests aboard that didn't flush properly and the vacuum pump ran continuously. I was at the helm and didn't hear the pump running, which ended up burning out. The replacement was $250. I added an in-line 12v timer that you can adjust the run time. I think it cost around $15. Best peace of mind I ever bought.
P.S. Don't be on a boat with five other dudes with the only toilet broken!

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You should have no need for a timer, that just bandaids the situation and does not cure the root cause of the problem. These are very simple systems. One of those pumps would have to run a very very long time to "burn out".

caltexflanc said:

One of those pumps would have to run a very very long time to "burn out".

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Yeah, like months or years perhaps.

caltexflanc said:

You should have no need for a timer, that just bandaids the situation and does not cure the root cause of the problem. These are very simple systems. One of those pumps would have to run a very very long time to "burn out".

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This is not a bandaid. A vacuflush toilet requires a proper flushing technique. If you do not flush properly, the system does not seal properly and the pump keeps running in an attempt to build proper vacuum. This is what happened to me. I couldn't hear the pump running due to the engine running. I ran a total of 10 hours max and the pump burned out. This is not a hypothetical situation. It happened. Why you wouldn't add a $15 part to have a toilet at the end of a cruising day is beyond me. Boating is all about being prepared.