vanity unit Toilet pan failing to drain properly any advice appreciated

[scottplumber]

Hi guys,
im currently instaling a bathroom in a very old house as you could imagine nothing is square and plumb anyways i have removed the old toilet which had a lot bigger cistern than the one im installing at the moment. The toilet going in is a vanity unit with a concealed cistern and pan from the bath store. The problem im having is its taking 2 flushes to get rid of toilet paper i have adjusted everything properly in the cistern and the water is at the maximum height of 6ltrs. The soil pipe was sloping down towards the toilet a little bit but have managed to chip away cement around the soil pipe inside and out and get it straight but cant take it any further down so it would have a fall leaving the house into a branch connection from the soil stack because they have an extension and they have a sloped roof is literally underneath it. Even if i cut the soil pipe and made it a little shorter i dont think that help me as the problem is from inside the bathroom to directly outside. i really wouldnt put the pan on a plinth it would look terrible.

sorry if this doesnt make much sense but please help its driving me crazy lol

thanks

 

[SimonG]

Change the innards of the cistern to give you a 9 ltr flush. Modern toilets and cisterns are garbage. We've move from a 2 gallon flush (9 ltrs) to 6 ltrs to save water, only trouble is custs are flushing twice to get rid of the stuff in the pan.

Or try a different pan with a bigger hole!

 

[nicro3]

What is the height of the soil pipe? What is height of pan spigot? off the floor

 

[scottplumber]

Change the innards of the cistern to give you a 9 ltr flush. Modern toilets and cisterns are garbage. We've move from a 2 gallon flush (9 ltrs) to 6 ltrs to save water, only trouble is custs are flushing twice to get rid of the stuff in the pan.

Or try a different pan with a bigger hole!

So could I change the cistern to 9ltr that sounds the best option at the minute

 

[scottplumber]

I haven't measured it but from pulling the pan out and looking at the flexible pan connector where it connects to the soil pipe it's straight. I even tried testing if it would work better by putting the pan on some wood to lift it up abit still didn't work much better such a small thing causing such a big problem

 

[nicro3]

Check that cistern is not below manufacturers minimum height. How long is flexi?

 

[scottplumber]

It's a mcalpine flexi pan connector not sure on size exact size tho unfortunately it's long enough to extend it out and connect to the pan before pushing back to the unit . it wouldn't be lower than the manafacturers minimum because in the vanity uunit there's only one place to hang the cistern.

 

[nicro3]

Can I ask why you used a flexi pan con, is the soil far from your centre?

 

[scottplumber]

I used the flexi pan connector because the soil pipes a few inches back from the pan and it makes it easier to put it on the pan then push it back upto the vanity unit if that makes sense.

 

[Guest123]

The Flush valves/syphons in these BTW vanity units are rubbish. I fiited one this morning and swapped the syphon for a Siamp and this gives a really good flush, plus the Siamp is easy to replace as it twists off in the cistern from its sealing base.

Best combo for a concealed cistern is a Siamp flush valve/syphon with a Fluidmaster Pro side entry fill valve with brass shank. Both will last for years.