New Lavac Explodes!

[CarlF]

I've got two Lavacs. While they have their idiosycracies , I've never had anything like what you report. I'm betting it's a restricted inlet but try some more diagnosis:

Fill the bowl with water from the shower hose or a bucket. Pump with the lid open. It should pump easily. 20 pump strokes should empty it. If not - you have a blockage (hose or vent) downstream or a problem with the henderson pump.

Fill again. Add "solids". A few ice cubes might be good (and melt if there really is a clog). Pump. Should be about as easy as before.

Now try with the lid down. Pump 10 strokes (full strokes about 1-2 seconds per stroke). Stop. You should be able to hear water dribbling into the bowl for about 10 seconds after you stop. If you wait for the lid to release (you shouldn't be able to open the lid for 1-2 minutes) there should be 3-6" of water in the bowl that was sucked in by the suction.

The 10 pump strokes - wait 10 seconds - 10 pump strokes cycle is important with the Lavac. This gives rinse water a chance to fill the bowl. With experimenting you can learn to use fewer pump strokes. With solid waste I do a pump-wait-pump-wait-pump to get an extra bowl rinsing.

My guess is that too fast pumping, not pausing occasionally during pumping, and/or an inlet blockage is not letting enough flush water come in so that the bowl empties of water. Once the water level gets below the top of the bowl exit, air is drawn into the pump with each stroke. Those pulses of air would blow the last bit of waste around inside the bowl.

And an aside on TP. I never worry about TP in a Lavac (I am careful not to fill the holding tank with the stuff). In eight years I've never had a clog in the Lavac. My last head was more like a clog every eight days. Someone on this board claimed a Lavac could swallow a tennis shoe - I assume he was joking but how did he come up with that specific example?

Carl

[Dick Behan]

Today, with a bag of TaterTots as a reasonable facsimile of solid waste, I ran a bunch of tests. Nothing seemed to work, so I checked the installation against the owner's manual and found HUGE deficiencies in the way the Lavac was installed on my boat.

The inlet to the pump is at the top, the outlet at the bottom, so the flow is downwards--exactly opposite the instructions. And between the toilet and the pump there are 6 (yes, six) 90-degree PVC elbows, another horrible violation of the instructions.

Clearly the flow of solids is extremely restricted, and the inlet valve is failing to seal properly. The backflushing is hardly a surprise, as a result.

Stay tuned. I've notified the yard that did the work, and suggested we try again.

Dick B.
s/v Rowdy
PSC Flicka #314

[Bilgediver]

Originally Posted by glenda2

We have just had two new Lavac heads installed. They are wonderful except when the need comes to flush more than liquid. After solid waste has been flushed, I raise the lid and it has blasted the entire bowl and lid and seat with waste. Yuck!

I've tried different approaches to pumping. Have added water prior to a flush (there doesn't seem to be enough water in the bowl). 'Have at times pumped almost twice the times stated in the directions as it doesn't sound as if sufficient water is coming in (on the first 8-10 pumps). Have pumped slowly, quickly, or at high speed with no differences.

Our holding tank is above the height of the head in the forward part of the boat, below in the aft head. Both have the same problem.

And of course it is an intermittent problem!

The way yourm post reads makes me wonder if you have plumbed the Lavac correctly.

The lavac uses the pump to pump out the toilet and uses a standard diaphragm bilge pump of the correct size.

The water comes in entirely due to suction créated by the lid being closed.

You talk about lifting the lid. This is almost impossible to do while the toilet is ding its thing as the lid is held closed by the vacuum until the bleed nozzle has allowed enough air in to break the vacuum.

They do work fine with economy grade TP .

[YOGAO]

Dick Behan,

Another thing to check is the check valve (sorry!). I found one of mine had been installed backwards at the factory.

Once you get everything corrected and if you are pumping salt water, make sure you are on a regular schedule of giving the piping and pump a vinegar soak.

Fair Winds,
Mike

[glenda2]

Thanks to all of you for the responses. After checking out EVERYTHING suggested and thought of, it seems the pump was defective! We are now up and running and all is fresh smelling and a lot easier to keep clean (understatement).

Since we live aboard, this has been a long time very upsetting problem. It could have been solved when that early response suggested we call the manufacturer.

They are great heads and we are now very happy with them.

Thanks all,
Glenda2

[Southern Star]

Great to hear Glenda - having owned Lavacs on my last 2 boats I think you will find that they are a terrific product. As to the faulty pump, that surprises me (as they are just a bilge pump), but if replacing that and not re-running the hoses in accordance with the manufacturer's instructions fixed the problem to your satisfaction, then all is well.

Brad

[HHNTR111]

I've had Lavacs for 20 years, and they are a great product. The only time I had clogs was when the kids were first learning about TP...

[glenda2]

Thanks for your reply HHNTR111. We are now very happy with our Lavacs, too. They work much better when the pump is vertical, not horizontal (in the only place we had to put the pump). We had to purchase the electric flush pump in order to be able to put it further away from the head. Now it works very well. We didn't like the extra $250 but the only other option was to tear out our shower.

I'm surprised that you had a problem with TP when your kids were young. I understand you can get rid of old tennis shoes using them! :-)

[HHNTR111]

Well, for a while they thought that since some TP is good, more must be better...

[glenda2]

I think our kids and your
kids must be related!