Poo pump problems 🙁

[Sea Change]

My Lavac is refusing to do its job. Pumping the handle until I'm blue in the face, it just won't prime.
I've checked that both valves are free.
Maybe the diaphragm has failed??

Given the nature of the problem, I'd rather not go down too many dead ends looking for a solution.

Any help much appreciated!

 

[PaulRainbow]

A tiny object in a joker valve will do that, like the seed from bread.

 

[Concerto]

There is no joker valve in a Lavac.

I had the same problem recently with my Blake's Lavac. The solution is very simple. At the highest point of the inlet hose will be a small plastic insert into the hose. Remove this carefully and use a fine needle in the small vent hole in the insert. Now refit the insert. This hole slowly breaks the vacuum on the inlet water and if blocked, this locks up the pump as the outlet is larger than the inlet.

 

[VicS]

My Lavac is refusing to do its job. Pumping the handle until I'm blue in the face, it just won't prime.
I've checked that both valves are free.
Maybe the diaphragm has failed??

Given the nature of the problem, I'd rather not go down too many dead ends looking for a solution.

Any help much appreciated!

Assuming the pump handle moves back and forth freely.
Fill the bowl with water.. Leaving the lid open will it pump out normally. You should hear it noisily suck in air once the bowl is empty. If not the pump needs an overhaul.
If it pumps out OK the pump is probably OK.

Assuming the pump is OK check the seals on the lid and the seat. Both must seal properly in order to create the vacuum that draws water in.

If the pump does not operate freely with the lid open it, or the outlet, is blocked.

If it operates freely with the lid open but becomes difficult with the lid shut the inlet is blocked and probably the vent mentioned above.

 

[geem]

My Lavac is refusing to do its job. Pumping the handle until I'm blue in the face, it just won't prime.
I've checked that both valves are free.
Maybe the diaphragm has failed??

Given the nature of the problem, I'd rather not go down too many dead ends looking for a solution.

Any help much appreciated!

There is a flap valve on the inlet that may have something stuck in it keeping it open. You will need to undo the ring of screws and dismantle the pump. Or you could take the inlet pipe off and carefully push a pencil up the pipe connection to see if you can clear the obstruction on the inlet.
The pumps are a very simple diaphragm pump with a valve on the inlet and a jocker type valve on the discharge. If you haven't had the pump apart before, it may well be necessary to strip it and clean it. The only reason the pumps can really stop working is if you get a calcium like build up from lack of flushing. We always pump at least 20 times. 30 would be ideal

 

[BobnLesley]

The OP identified his toilet as a LAVAC, so where are people finding these joker and flap valves to investigate? VicS' post covers it ignore the rest

 

[PetiteFleur]

I also had this problem about 4 weeks ago - wouldn't pump out. Decided it was because we had our great grandson on board for a day and his mum had put 'something ' down the loo... I had completely rebuilt the loo two years ago with new inlet & outlet pipes and reconditioned the pump with gew valves etc. Tested it several times this week and it appears to be working OK. I might check the tiny vent as I forgot to check it.

 

[geem]

The OP identified his toilet as a LAVAC, so where are people finding these joker and flap valves to investigate? VicS' post covers it ignore the rest

The two valves shown in the spares kit. The flap valve is on the inlet. The jocker type valve is on the discharge

 

[lustyd]

I feel like everyone is missing the obvious here. OP must be hallucinating as Lavac’s never go wrong

 

[geem]

I feel like everyone is missing the obvious here. OP must be hallucinating as Lavac’s never go wrong

Your engine would go wrong if you never serviced it

 

[PaulRainbow]

The OP identified his toilet as a LAVAC, so where are people finding these joker and flap valves to investigate? VicS' post covers it ignore the rest

Or the OP could ignore you, as you clearly don't know what you're talking about.

 

[VicS]

I also had this problem about 4 weeks ago - wouldn't pump out. Decided it was because we had our great grandson on board for a day and his mum had put 'something ' down the loo... I had completely rebuilt the loo two years ago with new inlet & outlet pipes and reconditioned the pump with gew valves etc. Tested it several times this week and it appears to be working OK. I might check the tiny vent as I forgot to check it.

If the vent becomes restricted you end up with too much water in the bowl.
If it becomes completely blocked water will continue to siphon in if the inlet to the bowl is below waterline level.

Two vent inserts, with different sized pin holes, are provided. You choose the one which leaves the right amount of water in the bowl ........ not so much that the tangly bits dangle in it.

 

[IanCC]

There is a flap valve on the inlet that may have something stuck in it keeping it open. You will need to undo the ring of screws and dismantle the pump. Or you could take the inlet pipe off and carefully push a pencil up the pipe connection to see if you can clear the obstruction on the inlet.
The pumps are a very simple diaphragm pump with a valve on the inlet and a jocker type valve on the discharge. If you haven't had the pump apart before, it may well be necessary to strip it and clean it. The only reason the pumps can really stop working is if you get a calcium like build up from lack of flushing. We always pump at least 20 times. 30 would be ideal

The metal disc can also corrode. Can't remember the problem it causes but I had to replace mine .

 

[geem]

The metal disc can also corrode. Can't remember the problem it causes but I had to replace mine .

Do you mean in the centre of the diaphragm? I have never needed to change one. In fact, I have never changed a diaphragm yet. Full-time liveaboard

 

[Concerto]

View attachment 199430
The two valves shown in the spares kit. The flap valve is on the inlet. The jocker type valve is on the discharge

You are showing the service kit for a Whale Mk5 bilge pump, which is the pump for a Lavac. The OP stated he had a complete lock up, which was exactly what I experienced. Clearing the blocked vent valve solved the problem. The lock up is due to the outlet being larger than the inlet and once the toilet bowl is full nothing will work.

The only other problem I have had with a Lavac was when the pump physically broke, the lever the handle moves had sheared. It never locked up, just kept moving but doing nothing. For speed I just replaced the 40 year old pump as I expected other aged plastic parts could suffer a similar fate.

 

[PaulRainbow]

You are showing the service kit for a Whale Mk5 bilge pump, which is the pump for a Lavac.

In post #3 you said "There is no joker valve in a Lavac.", now you say the pump is for a Lavac ?

It is for a Lavac and it does show a Joker valve ?????

The OP stated he had a complete lock up

He says no such thing, he says the pump will not prime.

which was exactly what I experienced. Clearing the blocked vent valve solved the problem. The lock up is due to the outlet being larger than the inlet and once the toilet bowl is full nothing will work.

This is not correct. Vic describes what happens with blocked vents in post #12

That's because the pump pumps out of the bowl, which tries to create a vacuum (Lavac), this draws the flush water into the bowl. It matters not that the inlet and outlet are different sizes.

 

[Sea Change]

Thanks all. And I'm surprised that a question about a toilet can generate almost as much disag as one about anchors!

I'm no stranger to working on these pumps, I've been full time liveaboard for over four years ago; this is not my first rodeo. But normally it's a blockage which stops the handle from moving at all, and the cure is to empty whatever delights are in the pump, and slosh around a bit of vinegar to break up the worst of the calcium buildup.

I haven't had one completely fail to prime before. It's creating a slight amount of suction at the lid, but not enough to actually draw anything out of the bowl. Pumping with the lid open just agitates what's in the bowl but the level doesn't change.

Anyway it's very early here (I'm in Delaware Bay) and I'm going to have my breakfast before I face the problem again.

 

[rogerthebodger]

I had a similar issue sone time ago and found that the lid seal would not seal correctly due to damage on the sealing edge. I replaced the lid/ seat seal and it now pumps like a Goodan

 

[PaulRainbow]

Thanks all. And I'm surprised that a question about a toilet can generate almost as much disag as one about anchors!

I'm no stranger to working on these pumps, I've been full time liveaboard for over four years ago; this is not my first rodeo. But normally it's a blockage which stops the handle from moving at all, and the cure is to empty whatever delights are in the pump, and slosh around a bit of vinegar to break up the worst of the calcium buildup.

I haven't had one completely fail to prime before. It's creating a slight amount of suction at the lid, but not enough to actually draw anything out of the bowl. Pumping with the lid open just agitates what's in the bowl but the level doesn't change.

Anyway it's very early here (I'm in Delaware Bay) and I'm going to have my breakfast before I face the problem again.

See post #2.

If the outlet valve isn't completely closed it does exactly what you describe, it won't suck from the bowl, because it's easier to suck from the outlet.

 

[geem]

See post #2.

If the outlet valve isn't completely closed it does exactly what you describe, it won't suck from the bowl, because it's easier to suck from the outlet.

It could be, but if it's not priming, I have found the first pump on the handle returns the water back to the bowl due to a stuck inlet valve. A longer inlet pipe to the pump makes the problem worse as a single stroke of the pump won't get liquid to the pump body