Lavac toilet , no water coming in through supply tube to pan

[robind]

Hi I am guessing that more than one of our member, will have had the same (or similar) problem with a Lavac toilet! the model is the plastic lidded, full sized pan model, about 20 plus years old! or more, its been maintained well by the previous owner of the vessel! and at present it builds up a great head of suction, but it appears that as the seat still maintains that vacuum for about 8 hours or more, that no water is getting in through the inlet tube? I know of some models of marine toilets where the duck beak valve can get turned inside out and have a similar effect ( not sucking water in) but I am stumped by this symptom, and can only think that maybe the sea water inlet is restricted in some way. The electric push button pump is obviously working OK, as, seems to be the rest of it, with liquids being sucked out of the pan without the apparent use of the vacuum. Any suggestions as to what could be the problem would be gratefully recieved. Thanks in anticipation
Rob!

 

[VicS]

Inlet seacock shut?
Strainer on the inlet blocked
But in either case the pin hole vent in the inlet pipe should release the vacuum

Conclusion
Pipe or inlet to the bowl is blocked. !!

 

[Liz_I]

Inlet seacock shut?
Strainer on the inlet blocked
But in either case the pin hole vent in the inlet pipe should release the vacuum

Conclusion
Pipe or inlet to the bowl is blocked. !!

+1

In addition should you wish to release the pressure when crew members are desperate! Put your fingertips under the rim and just lift the seal slightly, you'll hear a hissing sound as the vacuum is freed.

 

[VicS]

BTW User Manual for the Lavac HERE if you have mislaid your copy

 

[Hostage]

I have the manual version and my understanding is that the pump sucks the waste out of the bowl and in doing so it closes the lid tight thereby creating a vacuum in the bowl which in turn draws the clean water in.

If the lid stays tightly shut for a number of seconds after the waste is pumped out then there is a vacuum which should draw in the fresh water unless the inlet seacock or the inlet valve is closed or there is otherwise an obstruction.

Sorry but I cannot remember what type of valve there is on the inlet side which is likely to be the problem. Somebody here will certainly know.

Hi I am guessing that more than one of our member, will have had the same (or similar) problem with a Lavac toilet! the model is the plastic lidded, full sized pan model, about 20 plus years old! or more, its been maintained well by the previous owner of the vessel! and at present it builds up a great head of suction, but it appears that as the seat still maintains that vacuum for about 8 hours or more, that no water is getting in through the inlet tube? I know of some models of marine toilets where the duck beak valve can get turned inside out and have a similar effect ( not sucking water in) but I am stumped by this symptom, and can only think that maybe the sea water inlet is restricted in some way. The electric push button pump is obviously working OK, as, seems to be the rest of it, with liquids being sucked out of the pan without the apparent use of the vacuum. Any suggestions as to what could be the problem would be gratefully recieved. Thanks in anticipation
Rob!

 

[VicS]

Sorry but I cannot remember what type of valve there is on the inlet side which is likely to be the problem. Somebody here will certainly know.

Normally only the inlet seacock.

 

[theoldsalt]

The seacock on the inlet is usually a blakes.




Sometimes owners will remove the handle and rotate it through 90 degrees so the handle may or maynot line up with the mark on the spindle just to move it to a more convenient position.

I had this on my previous boat. It took me ages to realise that the valve was shut when it indicated open and vise versa. I thought there was a blockage however it disappeared when I turned the valve to what I thought was closed.

 

[DavidGrieves]

It can only be a blockage on the inlet side. If it's a Blakes type the strainer on the outside might be blocked. Mine was almost blocked with antifloul. If the seacock is a gate valve, the left hand thead central spindle can get stripped, you migt think it is open but the gate is still in the down position. Might be blocked with marine growth inside skin fitting ut if it's holding vacuum for 8hrs it's unlikely.

Try turning the seacock handle whilst under vacuum, if the handle has been altered as others have sugested you will hear water rushing into the bowl.

You could also try removing the inlet hose from the bowl end and blowing down it with a dinghy foot pump to try and clear the blockage.

As a last resort remove the hose from the seacock (carefully) open seacock slightly, if water rushes in then the hose must be blocked. Be VERY cautious when removing the hose from the seacock, it may be safer to cut the hose just above the hose tail, rather than subjecting it to the stresses of pulling on it. The last thing you want is a snapped skin fitting!!! Or if you can wait leave it until you are out of the water or dried out against a wall.

 

[VicS]

If the pin hole vent on the inlet pipe is not blocked (that can easily be checked with a fine wire or a bristle off SWMBO's tooth brush before pulling anything else apart) then the blockage is NOT at the seacock end or the vent would release the vacuum.

Therefore the blockage must be at at the bowl end of the inlet pipe or within the bowl itself.
Another forumite recently found the water channel in the rim of the bowl was blocked.
It could easily be blocked where the hose fits onto the inlet to the bowl.

Check the vent .
If OK
Close the seacock and take the hose off the bowl. Investigate in that area.

 

[clyst]

I have had a similar problem . It was small shells (like mussels) growing and blocking the inlet up under the bowl rim . Not a difficult job to do .

 

[robind]

Lavac no water in

A hearty thankyou to all you guys, who replied to my post re the lack of water to a Lavac marine WC, and so quickly too. All the suggestions are very practical and one is possibly going to sort the problem I hope.

Thanks again

kind regards

Rob

 

[Boathook]

The 'inlet' round the rim can get blocked by mud if the lavac was used when aground. If this is the case it would be easier to clean this out of the boat. Use a bit of thin plastic to clean all the holes and then a hose to blast clear. This will need doing a few times and possibly a few times after refitting.