Toilet poor flush

If you are in a hard water area the channel under the rim which carries the water to the front of the pan can clag up.

Worth investigating and perhaps squirting some strong cleaning product up there.

Cheers

Dave R

We had three new toiles installed about 7 years ago, all identical. One flushes very well, one is acceptable, and the one in our en-suite is a pain in the neck often taking three flushes to properly clear. As it was like this from the start I put it down to variations in slump during the firing in the kiln when made. If it wasn't so 'built in' I'd just swap it.

Andrew

David presented the following explanation :

No, we are in a very soft water area, there is never any build up on cold taps and just a bit on hot taps/ shower heads.

Isn't the s*it-shifting effectiveness of toilets a much a function of waste-pipe length and fall as it is water delivery into the pan?

Or how the toilet is connected to the soil stack, or the arrangement of the soil pipes? In a friends' rented house one downstairs toilet has a decent flush but the pan will not clear until 2 or 3 flushes. I suspect its because the outlet exits the house into a very short soil pipe capped with an air admittance valve. Their other toilet connected to a different soil pipe has no problems.

Yes Too much of a restriction and/or too much build-up of a positive pressure in front of the flushed material can result in it not moving effectively or returning after the flush.

Where does the pressure come from? The pipe between the toilet and soil stack should be empty, assuming it is upstairs. Even downstairs, the pipe runs to the drains aren't full - or shouldn't be. If you lift a manhole (personhole these days?) it should be dry, when a toilet is flushed the flow doesn't fill the pipe.

True, if there is a build up/blockage the game changes.

For trial purposes I think I might use a length of pipe insulation around the back. If that works, then look to engineer something more permanent and less visible.

I had not thought of pushing pipe insulation in the gap, thanks I will try that - I have some in stock. From memory it is a narrow slot around the rim. The initial flush begins with a good flow at the front, but that rapidly diminishes to just a good flow at the rear - that good flow at the rear then seems to counter any movement out of the bowl, rather than encourage it.

I doubt there is any problem with the soil pipes. Both empty immediately, with no increase of level in the bowls. The one upstairs goes at right angles from the U, to slope down through a cavity wall, directly into the soil stack, which is open vented at the top.

The one downstairs, goes vertically down through the floor slab, then slopes around 5 feet, down to a man hole. I regularly lift the covers and check for good flow with no build up, because 20 years ago the upstairs one did back up. Who ever had replaced the caste iron soil pipe had smashed the caste iron pipe to remove it and left a broken piece jammed in the pipe underground.

We have two identical toilet pans, installed in the mid 1980's. Since install the flush of the pan action has been less than adequate, but now a little worse(1).

What I am observing is the water is delivered mostly to the rear / back of the pan, just below the pipe, causing solid matter to just cycle down at the back then up again at the front, often for several flushes. So we keep a 1L plastic jug to hand, to fill with water, to assist the front to rear flush action. It suggests to me, that they would work fine, if only the flush water was made to come out of the front lip rather than the rear. Some flow does come out the front lip initially, but it soon stops, so it is possible.

(1) The flush tanks are low level, just above the pans, linked via a right angled pipe. Originally they had a dual flush that allowed the tank to fill to the line. I have since replaced everything in the tank with a new duoflush, but the duo mechanism insists on a slightly lower water level to function properly.

Has anyone any idea how I might be able to reduce the flow to the rear lip, to increase the flow to the front lip, as both a temporary test and maybe a more permanent fix if it works?

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Have a look with a mirror under the rim where the water discharges from the tank. I have Twyford loos and on one of them the plastic diverter which makes the water swirl under the rim to the front became dislodged allowing the water to simply run down the back of the pan.

It may need to be pushed back into the discharge pipe, but you may have to juggle around with it to get the water discharging equally around the left and right portions of the rim.

on 26/11/2018, David supposed :

Interesting - I have had both discharge pipes out of the bowls in the past, when laying new floors, I didn't see any plastic parts in there at all - there was just the plastic pipe, end cut square, inserted into a nylon bush with flanges to form a seal. I didn't install the toilets originally and as said there has been a poor flush issue since new. I wonder if the installer might have missed installing these diverters?

Harry Bloomfield was thinking very hard :

I have just checked it with a mirror and torch, along the rim. Inside the rim, at the end of the pipe, is a sort of restrictor - its either part of the porcelain or made of white plastic, forming a wide jet.

The rim is entirely open all the way around and quite wide, so plenty of scope to add some pipe insulation to make and test out a DIY diverter.

I rather expected the rim would have holes around it, rather than being wide open all the way around.

They are usually open - though I have seen the "holes all around" design a few times.

Harry Bloomfield was thinking very hard :

That was easier than I thought...

I have pushed pipe insulation in around 2/3rds of the entire diameter, leaving the 1/3rd gap at the front on the guinea pig upstairs loo. It has not made a perfect seal at the back, but has reduced it to not much more than a trickle I was thinking I might need to make a gap there to provide some flow. It will full receive a full functional test first thing in the morning, but a 'dry' run suggests it flushes much quieter, longer and does certainly increase the general flow from through the bowl, front to back.

More likely to be due to differences in what the toilet connects to sewer line wise.

Sounds like a result!

Is the pan completely level, not tilted back?

We were bedeviled with a toilet that had always flushed ok but suddenly got bad. I replaced the entire contents of the cistern. Changed the short down pipe.Checked for blockages etc. All to no avail. Iwas loathe to buy a new toilet as there would be no guarantee it would be any better but eventually succumbed and bought damn near the most expensive one.It is dual flush and I am astonished at how effective it is with a very small amount of water. It?s a black art. The only small problem was a split in the flexible connector at the rear. The split was on the top so it didn?t really leak that much but nevertheless had done a lot of damage to the carpet. I wondered if ingress of air at this point may have affected the siphoninc action.

Harry Bloomfield was thinking very hard :

That was easier than I thought...

I have pushed pipe insulation in around 2/3rds of the entire diameter, leaving the 1/3rd gap at the front on the guinea pig upstairs loo. It has not made a perfect seal at the back, but has reduced it to not much more than a trickle I was thinking I might need to make a gap there to provide some flow. It will full receive a full functional test first thing in the morning, but a 'dry' run suggests it flushes much quieter, longer and does certainly increase the general flow from through the bowl, front to back.

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Sounds like you may have it sorted.

I need a full report in the morning!