syphonic toilet overflow

[doitall]

Nope if they are put together correctly the water will not rise.

The low air pressure in the middle causes a syphon and sucks everything out, every time.

The half moon washer should be on the end/tip of the dip tune, so it seals the hole when you place the cistern on the pan.

 

[7777777]

done quit a few off these over the years,,, when called to these thay will not remove any thing from the basin even a single sheet of paper takes two flushes,,,,,, when dismantled its always the domed washer gone,,, when reassembled,,, it works great ,,, the tenants will usually remarked that was how it used to be before it went faulty,,ie basin filling up then taking the waste ,,,,,, some ive been to look as if they have never been repaired since new

 

[doitall]

The water definitely shouldn't rise, are you putting the half moon washer on the very tip of the bomb and so the flat side seals the hole.

 

[7777777]

an explanation may be the change of syphon,,,,, i use Dudley only ie,,, older syphons may be more efficient than the older ones thus the rise in level

 

[Nige F]

??? there is an article by royal Dalton regarding single syponic WC but cant see how it could be called syponic with one trap,,,,,

One trap cast in the ceramic of the pan - and the othe a lead one under the outlet cistern @ low level with a chrome straight flush pipe and a little air pipe off it - got the T shirt for 2 of those , from the 1930`s in an old hotel not to mention the 30+ other 2trap syphos in the " newer" rooms - nightmare the lot of them

 

[JohnD]

doitall

the ones I have seen, the flush fills the first part of the trap until the volume of water is enough to cause a syphonic action which "gulps" and sucks the contents of the pan and trap away, then the pan refills with residual water running down from the cistern. Long ago I remember the manufacturer's literature saying it was able to do this because the trap had two different internal diameters, or had a restriction in it. The trap opening at the bottom of the pan was relatively small compared to a washdown.

I wonder of what I am describing is a different design from the one you are describing.

 

[7777777]

nige yes see the idea behind that,,, never seen that set up though,, may be its used more abroad as some continental WC exit from below the pan ???? must admit you be well stuffed if one of them blocked

 

[doitall]

??? there is an article by royal Dalton regarding single syponic WC but cant see how it could be called syponic with one trap,,,,,

One trap cast in the ceramic of the pan - and the othe a lead one under the outlet cistern @ low level with a chrome straight flush pipe and a little air pipe off it - got the T shirt for 2 of those , from the 1930`s in an old hotel not to mention the 30+ other 2trap syphos in the " newer" rooms - nightmare the lot of them

Better flog the Tee shirt then Nige.

The pipe from the appliance that runs back into the soil vent, is actually an anti-syphon vent pipe, did the same job as an syphonic trap on a basin or a durgo on a stub stack

 

[doitall]

doitall

the ones I have seen, the flush fills the first part of the trap until the volume of water is enough to cause a syphonic action which "gulps" and sucks the contents of the pan and trap away, then the pan refills with residual water running down from the cistern. Long ago I remember the manufacturer's literature saying it was able to do this because the trap had two different internal diameters, or had a restriction in it. The trap opening at the bottom of the pan was relatively small compared to a washdown.

I wonder of what I am describing is a different design from the one you are describing.

What you describe John is an unvented soil pipe with maybe a long horizontal run.

 

[Nige F]

[The pipe from the appliance that runs back into the soil vent, is actually an anti-syphon vent pipe, did the same job as an syphonic trap on a basin or a durgo on a stub stack

Nah , not one of those the little pipe went into the pan between the 2 traps - it was hooked inside the flush pipe so it drew air as the flush water rushed past it into the bowl - and due to age most of the `orrible seals etc. leaked air in so it never worked well . Would`ve changed the whole pan but it went into a 3inch lead soil pipe buried in the wall with the lead trap (wiped) soldered in . It was eventually changed when a major refurb was done , and they tore out walls etc.

 

[doitall]

Not seen one.

 

[JohnD]

What you describe John is an unvented soil pipe with maybe a long horizontal run.

nope. 20" to the vertical vented soilpipe.

 

[doitall]

What you describe John is an unvented soil pipe with maybe a long horizontal run.

nope. 20" to the vertical vented soilpipe.

Ok vent blocked with a birds nest or something.

 

[Hugh Jaleak]

I remember being taught about syphonic W.C.'s at college, the single trap syphonic's were also referred to as a 'bulbus outgo' pan. The trap was restricted at a certain point, so when flushed it allowed the water to build up, filling the outlet and then inducing a vacuum to suck the contents of the pan out. Think there may have been something of a similar design in my Uncle's place at Sidcup in the 70's/early 80's before he had a refurb.

The Doulton double trap at my parents place did work as described, soon as flush was initiated the water level in the pan would drop. All was fine until the solid matter tried to get round the bend.... (It often didnt make it without help!) Pan was problematic from day one, the installers came back and took it out to check for problems and couldn't find anything external of the pan.

 

[JohnD]

...the single trap syphonic's were also referred to as a 'bulbus outgo' pan. The trap was restricted at a certain point, so when flushed it allowed the water to build up, filling the outlet and then inducing a vacuum to suck the contents of the pan out.

That's the sort I've seen. Good at sucking the pan and trap clean.

I'm glad I'm not the only one.