Toilet flushing poorly

NickA · Dec 18, 2019

I replaced a cheapy syphon with a fluidmaster adjustable one and since then it is not flushing quite so well. The sypon is correctly adjusted (I think) and empties the whole tank on a full flush. The problem seems to be it does not release the water quite as fast. The old syphon most of the water circulated the rim and flushed through the front of the basin creating a sort of cascade that landed in the neck of the bowl. With the new one more of the water is released around the rim so not creating a vortex.

To be honest i think the design of the sanitary ware (Shires) is finicky, the difference in flow seems to have tipped it over the edge so it doesn't flush properly.

I cleaned the jets and there was a bit of black mold, I could probably do a better job there with pipe cleaners. They didnt seem to bad really. I also gave it a bit of a going over with a plunger.

Final bit of info, the old system had a sort of float think in the siphons outlet tube. I think it probably sat on the sanitary ware making a seal and rose up the tube on flush. Asked around and no one had ever seen anything like it. Its a mystery what it was or whether it was part of the siphon or something separate. Foolishly threw it away with the old siphon. Kinda interested what that was as currently a mystery.

I'm at my wits end here, I know its a long shot but I wondered if anyone can give any advice?

Many Thanks

Stigster · Dec 18, 2019

Sounds like you had what's called a siphonic flush system installed. The pan is designed for such a syphon and won't work properly with a standard syphon like you have fitted now unfortunately. The thing that you threw away is called the "siphonic bomb" believe it or not. Your option are to try to find another siphonic syphon and bomb or change the pan sadly.

centralheatking · Dec 18, 2019

NickA said:
I replaced a cheapy syphon with a fluidmaster adjustable one and since then it is not flushing quite so well. The sypon is correctly adjusted (I think) and empties the whole tank on a full flush. The problem seems to be it does not release the water quite as fast. The old syphon most of the water circulated the rim and flushed through the front of the basin creating a sort of cascade that landed in the neck of the bowl. With the new one more of the water is released around the rim so not creating a vortex.

To be honest i think the design of the sanitary ware (Shires) is finicky, the difference in flow seems to have tipped it over the edge so it doesn't flush properly.

I cleaned the jets and there was a bit of black mold, I could probably do a better job there with pipe cleaners. They didnt seem to bad really. I also gave it a bit of a going over with a plunger.

Final bit of info, the old system had a sort of float think in the siphons outlet tube. I think it probably sat on the sanitary ware making a seal and rose up the tube on flush. Asked around and no one had ever seen anything like it. Its a mystery what it was or whether it was part of the siphon or something separate. Foolishly threw it away with the old siphon. Kinda interested what that was as currently a mystery.

I'm at my wits end here, I know its a long shot but I wondered if anyone can give any advice?

Many Thanks

tell you what, take the cistern lid off and send us a piccy , all may be not lost
centralheatking done loads of cisterns of all types on a commercial basis

Jim Goodenough · Dec 18, 2019

Stigster said:
"siphonic bomb"

You can buy these from Plumbers Mate.
Cheers Jim

moonlight · Dec 18, 2019

You can still buy the middle part you threw away. Not sure it would work with a modern siphon though. Good luck.

rpm · Dec 18, 2019

centralheatking said:
tell you what, take the cistern lid off and send us a piccy , all may be not lost
centralheatking done loads of cisterns of all types on a commercial basis

The photo you want is of the pan sideways on.
[automerge]1576704574[/automerge]

Jim Goodenough said:
You can buy these from Plumbers Mate.
Cheers Jim

Toolstation and Screwfix sell them.

NickA · Dec 19, 2019

Thanks for all your replies! I did try all sorts of searches but most returned float valves or nothing. In any case I would never have guessed 'siphonic bomb'. I’m away for a couple of days but will try to post a picture or two on my return.

The old siphon seemed pretty standard apart from the bomb so I might try and locate something. I guess our Xmas guests will be using the bucket!

Jim Goodenough · Dec 22, 2019

NickA said:
Xmas guests will be using the bucket!

Bucket n chuckit.....! 😁

moonlight · Dec 23, 2019

Here is the fix

View: https://youtu.be/lBD3GOZvIHE

Where to buy the bomb

Thomas Dudley Syvac Syphonic Aspirator Bomb

Dudley Syphon Air Extractor Aspirator Bomb. This aspirator is for syphonic pans, and is ideal for dudley syphons. The external diameter of the pressure reducing valve is 42mm.

www.plumbers-mate-sales.co.uk