Holding Tank Problems

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MYTraveler

MYTraveler

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My 100 gallon holding tank is pumped overboard by a Whale Gulp diaphragm (good thing for spell check, or I would have left out the silent "g") pump, which takes 20-30 minutes. During the last 6 years the diaphragm broke once, but otherwise no problems with the pump.

However, on two or three occasions, despite pumping for 60 minutes (by design, the pump can run dry without damage), the gauge continued to show full. I wasn't sure whether the gauge was bad or the pump had failed to pump. In both cases, I left the pump on, flushed the heads a few times, and ultimately the gauge showed empty.

Well, it happened again yesterday (with the gauge reading 3/4 full), so I added water (through the heads) until they wouldn't flush any more. Then, about an hour later I noticed the gauge was down to about 1/2 full, and 10 of 15 minutes after that, it was showing empty.

So, I suspect a "blockage" (the pump draws through a 1-1/2" tube that draws from the bottom of the tank), that resolves itself over time. Has anyone experienced this? Any suggestions?

I have two ideas. First, I may put a clear section of hose (probably after the pump so that the pump's suction doesn't collapse it, so I can see if it is pumping. Second, I may put a T-fitting and valve in front of the pump so I can force water backwards into the system. I am also thinking of putting a second valve so I can force the water through the diaphragm pump -- I don't see how that could damage it, right????

Any thoughts, suggestions, etc., greatly appreciated.
-Rick

One detail that might be worth mentioning -- my boat has a separate holding tank to service the day head. Same exact set up -- same head, same macerator, same type tank and draw pipe (different dimensions, 40 gallons vs. 100), and same diaphragm pump. This head has never had a problem.
 
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What tank gauging system do you have? Do you have a non-contact sensing system? It sounds like you are getting false readings via the gauge maybe.
 
It sounds like your level sensors are having a challenge.

I've seen the float switch type get buggered up with holding tank goop. Generally like you do, adding some water helps resolve the issue.
 
Larry M said:
What tank gauging system do you have? Do you have a non-contact sensing system? It sounds like you are getting false readings via the gauge maybe.
Click to expand...

That's what I was thinking. If you have a mechanical float gauge system, the float may be sticking until you flush the head. Do you have tank access that will allow you to tap on the side of the tank to determine an estimated content level?
 
Next time I am on the boat, I will try to figure out what the system is, and at least take some pics to see if anyone recognizes it.

What system works for you all?
 
I think the replies are accurate. I would rule out a sensor issue before suspecting the pump. I just had the same issue on our 70 gal holding tank. Had to have the holding tank opened, cleaned and the sensing unit repaired. I'm not onboard right now, and am drawing a blank on what the actual unit make/model was.

BTW, if the gauge reading is faulty, you may have at some point overfilled the holding tank. If so, if you have a charcoal filter in line to the vent loop, it'll need to be replaced if the contents got to that level.
 
Can you not see the discharge flow at the hull exterior?
 
On my friend's boat, he installed a y valve with a hose fitting so he can flush out the system with fresh water.
 
Is it a low water use toilet and the mix is in a semi solid state? Perhaps a laxative may help.
 
I vote senser issue too.

Once the tank is empty you should see bubbles coming up. You could also fill the tank with soapy water so you can see if the pump is pumping out if the water around your boat in is to dark to see the effluent coming out otherwise.

If you do put a clear section in you black water line I suggest using clear PVC as opposed to clear hose.

If this pump is on your big boat I would **** can, pun intended, the Whale pump and go with something more substantial. I not a big fan of Whales and two diaphragms breaking in 6 years is to two to many IMO and experience. It's usually the duck bills or flaps that need replacing first.

You might also consider adding a spring wound timer to the pump circuit so you can set it and forget it when it comes time to pump out.
 
"You might also consider adding a spring wound timer to the pump circuit so you can set it and forget it when it comes time to pump out." The timers solve lots of problems BUT most are made for AC , so the points do not live well cutting even modest DC loads. There cheap so buy 3 instead of one .
 
FF said:
"You might also consider adding a spring wound timer to the pump circuit so you can set it and forget it when it comes time to pump out." The timers solve lots of problems BUT most are made for AC , so the points do not live well cutting even modest DC loads. There cheap so buy 3 instead of one .
Click to expand...

I've been using them for years to control DC loads. And I can't recall having one fail yet. In fact I can think of 2 that I installed on one boat 5 years ago for the black water pumps that are still going strong today. But YMMV.
 
Capt.Bill11 said:
I vote senser issue too.

Once the tank is empty you should see bubbles coming up. You could also fill the tank with soapy water so you can see if the pump is pumping out if the water around your boat in is to dark to see the effluent coming out otherwise.

If you do put a clear section in you black water line I suggest using clear PVC as opposed to clear hose.

If this pump is on your big boat I would **** can, pun intended, the Whale pump and go with something more substantial. I not a big fan of Whales and two diaphragms breaking in 6 years is to two to many IMO and experience. It's usually the duck bills or flaps that need replacing first.

You might also consider adding a spring wound timer to the pump circuit so you can set it and forget it when it comes time to pump out.
Click to expand...

Capt. Bill:
Good idea about the bubbles. I will watch for that.

What pump would you recommend?

I am not sure I understand the need for a timer, since the mfg claims the pump can run dry without damage. On occasion, I have forgotten to shut off the pump and it has run 2-3 hours, but nothing to really be concerned about (right?).

Thanks,
Rick
 
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MYTraveler said:
Capt. Bill:
Good idea about the bubbles. I will watch for that.

What pump would you recommend?

I am not sure I understand the need for a timer, since the mfg claims the pump can run dry without damage. On occasion, I have forgotten to shut off the pump and it has run 2-3 hours, but nothing to really be concerned about (right?).

Thanks,
Rick
Click to expand...

The Sealand pump. Or if you want something really heavy duty look at a The Bosworth Co - Diaphragm Pumps

While I understand the pumps can run dry for hours and hours, what's the point? :D

Between the noise they sometimes make, the extra wear and tear on them and the power you're wasting, I just like having them on a timer.
 
What boat are you on, and why aren't you pumping out at the dock? 140 gallons is a lot to pump overboard.
 
Lutarious said:
What boat are you on,
Click to expand...

My boat -- not sure I understand your question.


Lutarious said:
and why aren't you pumping out at the dock? 140 gallons is a lot to pump overboard.
Click to expand...

Because it is easier to pump overboard, and I do it far enough off shore that I am comfortable that it isn't any kind of problem. As they say in the haz mat business "the solution to pollution is dilution".

Sorry to sound socially irresponsible, but I am a little thin-skinned about the amount of diesel I burn, the amount of meat I eat, and everything else I do that offends someone else's sense of propriety. From a purely scientific perspective, there is nothing wrong with pumping at sea (as compared to pumping at the dock).
 
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While my holding tank is above water so it can drain, I've a vendor who sucks up its content at $20 a month.
 
Rick

We are having similar issues. You want to accurately know the level of your holding tank, and so do I.

Om my boat I have an automated system that senses sewage in the tank and automatically triggers my onboard type 1 MSD to process that sewage.

The problem I found with the system is that the pressure type sensors the manufacturer used are inaccurate. The manufacturer knows of this issue and as good as they are, they do not have a resolution.

What I have done is to order a few ultrasonic fluid level sensors that I'm hoping will solve the problem. Here's a link to the user guide/brochure for them.

http://levelguardproducts.com/marine-rv/documents/LevelGuard_SensaLevel_Ultra_brochure_Feb2012.pdf

I'll let you know how they work.
 
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