40mm PVC waste to cast iron

[jwturpin]

Hello,

I am plumbing in a new downstairs loo using a macerator.

I have four questions:

1) The PVC 40mm pipe needs to connect with a cast iron soil stack. I have the tools (hole cutter, boss strap, 40mm adapter), question is what's the best substance to use as a gasket sealant between the boss and the cast iron pipe?

2) I am aware that the boss strap i have is designed for a PVC soil stack, and cast iron stacks are slightly smaller in diameter, so what is best to use as a bit of packing to ensure the boss tightens up nice and tight?

3) The pipe from the macerator has to go under a floor into the cellar, follow suspended from the cellar ceiling (solid stone), and out the old coal chute, along the outside wall and into the cast iron stack.

I have seen two installations already where the pipe comes out the macerator and almost straight up and out at least 3 meters on both installations, and from what I could see, thats means water would always remain in the vertical section of pipe

The macerator I have can pump up to 7m vertical, but is only going about 1/2 meter in total as it happens. My Q is as the pipe goes down first into the cellar, then up 1/2mtr at the coal chute, this in effect creates a U trap which would always have water in, doesnt sound good to me, although the instructions say its ok.

Is it ok?

4) What is the recommended fall gradient in the section that runs outside between where it emerges from the coal chute and plumbs into soil stack? (total length of approx 4.5 meters)

Many thanks in advance for clarification on these questions.

Jon

 

[SimonH2]

3) The pipe from the macerator has to go under a floor into the cellar, follow suspended from the cellar ceiling (solid stone), and out the old coal chute, along the outside wall and into the cast iron stack.

I have seen two installations already where the pipe comes out the macerator and almost straight up and out at least 3 meters on both installations, and from what I could see, thats means water would always remain in the vertical section of pipe

The macerator I have can pump up to 7m vertical, but is only going about 1/2 meter in total as it happens. My Q is as the pipe goes down first into the cellar, then up 1/2mtr at the coal chute, this in effect creates a U trap which would always have water in, doesnt sound good to me, although the instructions say its ok.

IIRC from when I put a Saniflow (though not for the solids) in the flat, the instructions were fairly clear that the rise had to be immediately at the pump and followed by the horizontal section. Dipped outlets (ie going downwards) weren't allowed, nor was a rise after a horizontal run.

You are correct that the vertical pipe creates a trap/water seal, the risk with a pipe finishing below the pump is that you could syphon out the entire contents of the unit (and pipework) and break the trap.

 

[jwturpin]

i'll re-read the instructions, I may have misinterpreted them.

To help illustrate, here is a picture of the installation: http://db.tt/49vd0l6

The toilet is going where you see the cat's litter box. A trap door to the left of the image closes to create a full floor.

If I am wrong and you are right, would it therefore be possible to place the macerator on the cellar floor under the where the toilet is, feed the toilet waste down a 110mm pipe to it, then I could have the rise coming immediately out of the macerator up to the cellar ceiling, rather than the macerator behind the toilet and the 40mm pipe going down through the floor and back up to the cellar ceiling which goes to the right at the foot of the stairs?

Jon

 

[hi1]

I'm impressed, is this to replace the cat litter tray, how did you train it to flush.

 

[Nige F]

Hello,

I am plumbing in a new downstairs loo using a macerator.

I have four questions:

1) The PVC 40mm pipe needs to connect with a cast iron soil stack. I have the tools (hole cutter, boss strap, 40mm adapter), question is what's the best substance to use as a gasket sealant between the boss and the cast iron pipe?

Jon

a hemp grommet smeared with silicone/mastic/gutter seal

 

[jwturpin]

I'm having trouble sourcing a gasket, when you say hemp, could you elaborate, or point me in the right direction? cheers

 

[SimonH2]

I'm impressed, is this to replace the cat litter tray, how did you train it to flush.

http://www.wikihow.com/Toilet-Train-Your-Cat

http://www.youtube.com/watch?v=8C4pzEgncFY
http://www.youtube.com/watch?v=zQbHS4YJOMc
Isn't that what Youtube was made for

 

[Nige F]

I'm having trouble sourcing a gasket, when you say hemp, could you elaborate, or point me in the right direction? cheers

PTS plumbers merchants will sell you a small plastic container of it - it`ll last you for years - Then have a google and watch some people fann y ing about with it . Get a nice fat long ish strand and size it for your grommet . then simply wrap one end round the ring formed - like when you tie a shoelace - easier to do than explain keep wrapping one end round then do same with other end - forming a ring or grommet . then smear it with silicone which will stick it to the plastic strap -fit and leave for a day to set, then run water thru` it . If any water gets past the silicone it`ll cause the hemp to swell and it`ll be self sealing .