Lavac toilets not releasing vacuum

stuartwineberg

stuartwineberg

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My friend has just got an Aquastar 118 with two heads, both Lavac electric. They build vacuum and flush fine but neither will release the vacuum so it can be a couple of hours before you can open the lid. AFAIK they are set to discharge over the side so I don't think holding tanks are the issue but I may be wrong. Any ideas?
 
stuartwineberg said:
My friend has just got an Aquastar 118 with two heads, both Lavac electric. They build vacuum and flush fine but neither will release the vacuum so it can be a couple of hours before you can open the lid. AFAIK they are set to discharge over the side so I don't think holding tanks are the issue but I may be wrong. Any ideas?
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Air bleeds in the inlet hoses blocked.

on the top of the inlet hoses at the highest points of the antisyphon loops you should find little plastic inserts with a pin hole through them. Clear the pinholes

See the Owner's operating and installation manual on the Blakes Lavac Taylors website

http://www.blakes-lavac-taylors.co.uk/prod03.htm
 
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I've seen quite a few lavac loo's not fitted with air inlet valves.
A solution is on the inlet hose from the seacock the pipe should loop high before entering the back of the loo.
At its highest point drill a 2mm hole in the top of the pipe.
When you pump and create a vacuum the tiny hole won't really effect the water coming in but it is big enough to release the loo seat in around 30 to 40 seconds.
 
Erm, when I looked briefly at converting our Lavac manual pump to an electric pump ISTR mention of a solenoid operated anti-syphon valve operated by the pump timer (i.e. the air inlet is closed whilst the pump is running for max pumping effect and then automatically opened to release the vacuum and prevent syphoning)

If your installation has such a beast it may be faulty. Or it may never have been fitted in the first place
 
Erbas said:
Erm, when I looked briefly at converting our Lavac manual pump to an electric pump ISTR mention of a solenoid operated anti-syphon valve operated by the pump timer (i.e. the air inlet is closed whilst the pump is running for max pumping effect and then automatically opened to release the vacuum and prevent syphoning)

If your installation has such a beast it may be faulty. Or it may never have been fitted in the first place
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Where did you find this? its not mentioned in the manual on the website. Was it in connection with the new type of electric pump now fitted because it has a much lower pumping rate than the old type.
 
Apologies, the solenoid operated syphon breaker is a Jabsco item, not a Blakes Lavac job at all

I shall go and hang my head in shame
 
Erbas said:
Apologies, the solenoid operated syphon breaker is a Jabsco item, not a Blakes Lavac job at all

I shall go and hang my head in shame
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It sounded quite a reasonable possibility because I think the type of pump now used in place of the old motorised manual pump has a lower pumping capacity.

Because of this I would hesitate to drill a hole as large as 2mm in the inlet hose. The pin holes supplied are not as large as this I am sure.
 
VicS said:
It sounded quite a reasonable possibility because I think the type of pump now used in place of the old motorised manual pump has a lower pumping capacity.

Because of this I would hesitate to drill a hole as large as 2mm in the inlet hose. The pin holes supplied are not as large as this I am sure.
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Mine was supplied with two different hole sizes - neither of them anywhere near 2mm. Hot sailmakers needle through a Bic pen plug does the job. Think the hole in the tube for the plug is 4mm but easy to measure when you have the plug.
 
VicS said:
Air bleeds in the inlet hoses blocked.

on the top of the inlet hoses at the highest points of the antisyphon loops you should find little plastic inserts with a pin hole through them. Clear the pinholes

See the Owner's operating and installation manual on the Blakes Lavac Taylors website

http://www.blakes-lavac-taylors.co.uk/prod03.htm
Click to expand...
Vic's absolutely right (he usually is!).

Weve got a manual Lavac and had the same issue when we first bought the boat. Turned out someone had taped over the pin-hole valve, probably because they thought there was a leak! The seemingly constant urgent need of small people with small bladders prompted me to investigate why it was taking 20min to release the vacuum and, hey presto!
 
+1 for checking the bleed hole in the top of the anti syphon loop.
We had the same problem when we replaced the loo, and therefore had fully operating seals again. Couldn't open the lid for aaaaages! Discovered the tiny little hole was blocked with crud.
 
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