Syphonic toilet - poor performance.

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We have a syphonic toilet (about 20 years old) and the problem is when it is flushed it always leaves paper behind and has to be flushed again.

I tried replacing the syphon with a normal one but it made the problem far worse and it wouldn't even get rid of a single sheet of paper, also the water level in the pan rose almost to spillover! So I had to put the old syphon back on. The old syphon had some kind of removable dip tube or restricter thing in the end of it unlike the new one.

The toilet always flushes on the first pull and the syhon 'diaphram' is in good condition.

Can someone explain the difference between a syphonic toilet and a normal one? and how to make this thing flush properly.

The only reason I know its a syphonic toilet is that the previous owner mentioned it.

Many thanks.
 
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Good idea in principle these things but are prone to blocking. I broke one open once after removing it to look inside, they restrict quite severely inside to assist with the syphonic action, hence solid matter can (and does!) get stuck. I think they were designed to give a virtually silent flush, (coupled with a Torbeck float valve noise during/after flushing was virtually non existent outside the room).

These pans contain a two water filled traps, one in the bowl and another inside the pan. The item in the syphon tail is an aspirator or 'bomb', this, when water passes over it as flush commences, causes a vacuum in the middle section of the toilet, allowing the syphonic action to start and remove the contents of the pan by suction as opposed to washing them away as a normal pan should.

As you've discovered, if the 'bomb' doesn't work properly, the pan dont work either! Problem you have is not with the syphon, its the bomb. It may require replacement, or at least, a new washer, if its not air tight where it enters the middle chamber under the syphon tail it wont work. Bombs I think are specific to the type of syphon/pan, somewhere to look is:
http://www.lunns.net/cisternspares/
About half way down the page, or ask your local plumbers merchants, may be able to order for you. The bomb needs to be fitted and the cistern refitted onto the pan with extreme care, the bottom washer on bomb tail must give airtight seal around tail, and onto pan where the tail enters middle chamber, or else, as said, it wont work!!!
 
An extremely informative reply, thankyou very much.

Had a look on lunns and they have a couple of 'bombs' at £30 but my toilet is a royal doulton not armatige.

I suppose I could get a syphon to match but I'd be better off getting a cheap new toilet.
 
Ah, I know the one! Still have my old Doulton Pampas pan and cistern in the garage. Missing the bomb though!

Depends what colour your suite is, white not a problem, but if you've a coloured suite its not always practical to change the lot cos of a dodgy W.C.!
 
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Position the half moon washer right on the end of the tube so it's just sticking out a couple of mm, and it will work fine.
 

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