Toilet vented loop

donm

donm

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I had an insurance survey during the winter and the surveyor suggested/recommended a vented loop to the wc discharge pipe. So I bought and fitted one (even though the installation was sound) but having just gone afloat and checked it I find that the vent valve is leaking water and is noisy, so something is not working. Or should it be leaking and needs to be piped out!
Before I take it off and investigate, has anyone had a similar experience?
 
My syphon break makes a sucking noise when in use but doesn't leak, though it is on the inlet side but functions in the same way.
 
donm said:
I had an insurance survey during the winter and the surveyor suggested/recommended a vented loop to the wc discharge pipe. So I bought and fitted one (even though the installation was sound) but having just gone afloat and checked it I find that the vent valve is leaking water and is noisy, so something is not working. Or should it be leaking and needs to be piped out!
Before I take it off and investigate, has anyone had a similar experience?
Click to expand...

What make of toilet ?

No vent required on the outlet from a Lavac but (all ? ) others should have a vented loops ( inlet and outlet) if the top of the toilet is below water line at any angle of heel

eg for Jabsco

1651177611979.png
 
donm said:
I had an insurance survey during the winter and the surveyor suggested/recommended a vented loop to the wc discharge pipe. So I bought and fitted one (even though the installation was sound) but having just gone afloat and checked it I find that the vent valve is leaking water and is noisy, so something is not working. Or should it be leaking and needs to be piped out!
Before I take it off and investigate, has anyone had a similar experience?
Click to expand...
The vent should not leak at all. It should close/seal under pressure but open only when there is a vacuum to allow air in.

www.solocoastalsailing.co.uk
 
Thanks for the feedback. I really didn’t think that it should leak but just wanted to check!
I’ll take it out and remove the valve to check it it’s sealing.
I think I paid around £15 for a Lalizas bend but I see that the Jabsco bend is about £38! Is it really that different/better?
 
Whichever one you buy, be aware that the cheaper plastic ones can leak if the nut at the top holding the valve rubber in place isn't tight enough and can distort the valve rubber if overtightened. It seems to be a fine line between the two.
 
johnalison said:
My syphon break makes a sucking noise when in use but doesn't leak, though it is on the inlet side but functions in the same way.
Click to expand...
If its a Lavac thats normal. If the noise stops you need to unblock the little air vent

If its a Jabsco or similar it's in the wrong hose, as Thinwater says, but you'd probably get very poor flushing

( the anti-syphon loop for a Jabsco should replace the short hose fitted when supplied between the pump and the inlet to the bowl)
 
donm said:
Thanks for the feedback. I really didn’t think that it should leak but just wanted to check!
I’ll take it out and remove the valve to check it it’s sealing.
I think I paid around £15 for a Lalizas bend but I see that the Jabsco bend is about £38! Is it really that different/better?
Click to expand...
Some vented loops do not have a valve but have a nipple to which a tube can be connected and lead to a high mounted hull overboard fitting These are usually used in engine cooling systems as a pee indicator to show that the sea water is circulating through the engine and so designed to leak

If yours does not have the pipe nipple than you may have a stuck valve.
 
On a Lavac inlet one should not use the conventional vent with a valve (as depicted in post#4). The Lavac fitting (supplied in two sizes) that provides a tiny hole in the top of the loop of the pipe is all that is required - a syphon break.

The Lavac inlet pipe is (unlike Jabsco types) never under pressure, so a valve in a fitting will never close, while under suction (when pumping out) a standard valved fitting will very likely allow too much air into the pipe, requiring excessive pumping, and reducing flushing action and the amount of water left in the bowl after use.
 
Last edited:
johnalison said:
No. It is installed between the pump and the bowl but after each stroke it opens to let air in, which is audible.
Click to expand...
No bad thing to hear the valve is ‘working’…!

I’m about to reinstall our Jabsco with vents on both hoses. Surely either can siphon?
 
johnalison said:
No. It is installed between the pump and the bowl but after each stroke it opens to let air in, which is audible.
Click to expand...

Thanks again.

I fitted the Jabsco about 10 years ago and its is clearly a case of RTFM as the instructions (as you correctly point out) show that a vented loop should be fitted to both outlet and inlet, and that the factory supplied inlet pipe should be removed and redirected to include a vented loop between pump and pan, so I have only done half the job! I will sort the inlet before looking again at the outlet!

Thanks all for the information - I am now on the right track.

Don
 
donm said:
Thanks again.

I fitted the Jabsco about 10 years ago and its is clearly a case of RTFM as the instructions (as you correctly point out) show that a vented loop should be fitted to both outlet and inlet, and that the factory supplied inlet pipe should be removed and redirected to include a vented loop between pump and pan, so I have only done half the job! I will sort the inlet before looking again at the outlet!

Thanks all for the information - I am now on the right track.

Don
Click to expand...

I have rectified the inlet with a vented loop but (as expected) this has not stopped the outlet loop valve leaking noisily. I have taken the ducksbill valve out and it does not seem to able to fully (and naturally) seal so still a problem. I guess that it is meant to default to a sealed state unless forced to open by a vacuum caused by the end of pumping?

So I buy a new bend as getting the correct seal looks to be something of a lottery,................................................. or shall I just plug the seal hole on the outlet!
 
donm said:
I have rectified the inlet with a vented loop but (as expected) this has not stopped the outlet loop valve leaking noisily. I have taken the ducksbill valve out and it does not seem to able to fully (and naturally) seal so still a problem. I guess that it is meant to default to a sealed state unless forced to open by a vacuum caused by the end of pumping?

So I buy a new bend as getting the correct seal looks to be something of a lottery,................................................. or shall I just plug the seal hole on the outlet!
Click to expand...
Replacement valves are available . No need to replace the loop.
Jabsco 29015-1000 - Valve for Vented Loop / JABSCOshop Spare Parts / Xylem JabscoShop - Jabsco & Rule Pumps and more - from the experts

If you plug the vent you will be relying on the joker valve and the "twist and lock" feature to prevent syphoning.
You could always shut the seacock every time of course
 
VicS said:
Replacement valves are available . No need to replace the loop.
Jabsco 29015-1000 - Valve for Vented Loop / JABSCOshop Spare Parts / Xylem JabscoShop - Jabsco & Rule Pumps and more - from the experts

If you plug the vent you will be relying on the joker valve and the "twist and lock" feature to prevent syphoning.
You could always shut the seacock every time of course
Click to expand...


The culprit was the diverter valve which was failing to shut, so that all I was doing was pumping the Bristol Channel through the pan as at no time was it isolated.
A little attention to the valves and seats and the jobs a good 'un

Thanks all
 
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