weak toilet flush

[Boilersuit]

I've tried cleaning out the jet channel that goes from the cistern into the toilet pan (there's only one). It seemed fine, not a huge amount of sediment coming out of it & no problem getting a wire to pass all the way through it.

I've re-installed the syphon again.

Nothing's working! At the end of my tether here tbh, might just call a professional ¯\(ツ)/¯ thanks for all the help guys!

 

[Chuck]

I can't see any cracks in the syphon. It's brand new so I really hope there's no cracks.

I meant in the original. A crack or split seam would fit the symptoms and explain the sudden onset.

 

[Boilersuit]

I meant in the original. A crack or split seam would fit the symptoms and explain the sudden onset.

Ah fair. Well I got a replacement syphon & still have the same problem

 

[Deleted member 120897]

What about trying removing the cistern again, and running some water into the pan inlet where the syphon would sit, see if this helps with anything?

 

[Boilersuit]

Hope it's ok to resurrect this thread!
I left this be for a while cos of life commitments etc. But I'm back at it now.

I noticed the syphon pump actually pulls in water as it is flushed. You can see it gurgling up,see the video.
I can't figure out why it does this, but it definitely is part of the problem as it means the water doesn't get pushed strongly up & over down the flush pipe into the bowl.

Just a recap this is my THIRD new syphon that flushes weakly like this, it's the more expensive fluid master one.

 

[snowhead]

In a word,,, Rubbish.
The water should move far quicker than that.
How far above the bottom of the cistern is syphon?

That demonstration is giving the impression that the flush pipe is filling up and not allowing the syphoned water to pick up speed, assuming there is clearance under the syphon to allow the water to get into it.

 

[Boilersuit]

In a word,,, Rubbish.
The water should move far quicker than that.
How far above the bottom of the cistern is syphon?

That demonstration is giving the impression that the flush pipe is filling up and not allowing the syphoned water to pick up speed, assuming there is clearance under the syphon to allow the water to get into it.

It's about a quarter of an inch above the bottom of the cistern right now (and in that video). It's an adjustable-height syphon so I have tried it at a few different heights. Does the same whatever height I set it to.

 

[ShaunCorbs]

Cut one thread off the bottom of the siphon worth a try

 

[Boilersuit]

Cut one thread off the bottom of the siphon worth a try

Just tried that. Reconnected everything & nothings changed. Flush still very weak, syphon still sucking in water

 

[ShaunCorbs]

Try pouring a bucket where the pan hole is eg the cistern / siphon goes on

 

[Boilersuit]

Try pouring a bucket where the pan hole is eg the cistern / siphon goes on

Did this a good few times. The water goes through like you'd expect

 

[ShaunCorbs]

Ok remove the siphon from the carrier eg undo the red clip and lift the right half off and pour a bucket down the tube

 

[Boilersuit]

Ok remove the siphon from the carrier eg undo the red clip and lift the right half off and pour a bucket down the tube

OK did that. Not sure what I'm looking for tbh.
The water comes into the bowl in a fairly weak stream, but that could be because I'm just pouring a bucket

 

[Chuck]

This is turning into quite a saga.

Have you tried taking the cistern outside and testing the siphon's operation with a bucket under it instead of the pan? This would at least tell you whether the issue was with the cistern, which I think is less likely after you've tried three siphons, or blocked channel(s) in the pan, which is where my money is.

 

[Boilersuit]

This is turning into quite a saga.

Have you tried taking the cistern outside and testing the siphon's operation with a bucket under it instead of the pan? This would at least tell you whether the issue was with the cistern, which I think is less likely after you've tried three siphons, or blocked channel(s) in the pan, which is where my money is.

I'm so sick of this toilet by now!

So I haven't tried that exact thing, I'll give that a shot soon & report back.
I'm starting to think it could be blocked channels too, but also have been poking at them a lot & not noticed any major blockage.

 

[Ric2013]

1/4" from the bottom of the cistern sounds a tad tight, but not excessive. Just to make sure though... wedge a pencil between the cistern and the underside of the siphon and try flushing again. I'd just want to be sure the vacuum of the siphon isn't pulling the siphon up against the cistern floor.