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04-Toilet Ventilation system


le-cerveau

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It has been a while since I posted and things are progressing, so expect a flurry of posts in the next few months as things are decided before we go to contract, however I have been working on some minor detailing.  I have decided that I want to extract toilet smells directly from the pan (see JSHarris blog part 32)

I have 6 toilets in the house, in 3 pairs (see the plans on blog 02-The Planning Saga) so can use 3 extract runs, one to each pair, the simple bit.  I then need to work out how to connect to the MVHR system and the toilet cistern.  The MVHR ducting will be Hybalans+, thought the design/supply/install is still be to sorted out.  So I have 3 issues to work out: 1 connecting to the cistern, 2 connecting to the MVHR, 3 connecting the two together.

  1. Connecting to the cistern.
    After much research looking at low flush toilets and attempting to get information from suppliers (as soon as you go for non-standard ideas they all clam up) I discovered the Geberit Duofresh with build in odour extraction and started enquiring with Geberit about getting the connecting pipe from cistern to pan and using it on a standard cistern.
     Duofresh1.png   Trying to get this bit.   Duofresh2.png
    The issue being that the bit I want is not available as a part and is solvent welded to the cistern, however after much toing and froing of e-mails and finally a call from the technical department it was agreed that by using the Duofresh cistern (available without the filter and fan unit) I could cut through the pipe and connect it to the MVHR system.  The plan is to cut the vent pipe (it is 50mm) and put on a solvent weld joint with reducer and 40mm push fit adaptor (reason for 40mm push fit later).  I was also planning to seal up the feed into the cistern (vertical pipe) however this is square post the transition bend so not going to be so easy (can’t use a 50mm plug) so I may end up just filling it with expanding foam to seal it.  I have decided on the Geberit cistern as the ability to service them once installed appeals and the Duofresh cistern is only about £10 dearer than the standard cistern.

  2. Connecting to the MVHR.
    I then needed to work out how to connect the pipe to the MVHR system, the pipe coming from the manifold will be either 92/75 or 75/62 (external/internal dimension) and connect it to two 40mm pipes.  I then realised that soil pipes are 110mm standard and the vent terminals are between 100 &125mm so there was some potential there.  My solution (still to be tested) is to use a vent terminal adaptor onto a solvent weld pipe, my reasoning as follows:
    The 110mm soil pipe has an outside diameter of approximately 110mm and the solvent weld socket has an outside diameter of 121mm.

    Table1.png
    Table2.png
    The straight vent connector has a diameter of 125mm, the 900 one 118mm, however the vent inserts show a diameter of 114mm, so I suspect the 125mm is an external and the 118mm internal.
    Straight.png   90Deg.png  Insert.jpg
    The straight vent connector has a diameter of 125mm, the 900 one 118mm, however the vent inserts show a diameter of 114mm, so I suspect the 125mm is an external and the 118mm internal.
    I should be able to connect the vent terminal adaptor over the plain pipe with a push fit sealing ring on it and solvent weld a plug into the other end.
    Adaptor.png  Seal.png  Plug.png  Boss.png
    Then insert two 40mm push fit boss adaptors into the bosses on the pipe.
    I should now have an adaptor that connects the 92/75 MVHR pipe to (1-4) 40mm push fit waste pipes.

  3. Connect the MVHR adaptor to the cistern connector.
    With 40mm push fit sockets on both ends it is a simple job to connect up the two ends either with flexible 40mm pipe or rigid with a length of flexible 40mm pipe at each end:

    Roll.png  Connector.png  Short pipe.png
    So now I have a plan to connect the toilets to the MVHR.

The Geberit parts number is:
111.353.00.5 (Geberit Duofix frame for wall-hung WC, 112 cm, with Sigma concealed cistern 12 cm, for odour extraction with recirculating air)

The normal cistern is:
111.383.005 (Geberit Duofix frame for wall-hung WC, 112 cm, with Sigma concealed cistern 12 cm, wall anchoring and connection bend)

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Phew!  That sounds very complicated.  I think we'll just let the MVHR take the smells away as normal.  Let us know if it works.o.O Maybe after a curry night......

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Reading both your and Jeremy's posts on this topic, its the connection to the MVHR ductwork that seems to be the biggest problem / obstacle.  I'm using semi rigid 75mm airflex duct so facing the same issue if i want to go down this route.  Just had a look at my concealed cistern and it look to be straightforward enough in terms connecting to that using one of the punch outs.  

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Just as a completely random idea - how about the tee from a downpipe diverter for rainwater as they are 65mm round to a 25mm ish flexi normally..? 

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Thanks @le-cerveau for this post. It's high-quality, thoughtful, data-rich posts like these that makes all our lives just that bit easier.  And our scatological moments a little less unpleasant. 

 

I really appreciate the effort made.

 

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The part number works with UK suppliers:

111.353.00.5 (Geberit Duofix frame for wall-hung WC, 112 cm, with Sigma concealed cistern 12 cm, for odour extraction with recirculating air)

 

But when I try and source the same items from our friends in Germany (eg Megabad), it don't work. Seems like they have different part numbers between UK and Germany?

 

I can find two options on megabad:

111.370.00.5

https://www.megabad.com/hersteller-geberit-spuelkaesten-montageelemente-unterputz-spuelkasten-a-150057.htm

111.364.00.5

|https://www.megabad.com/hersteller-geberit-spuelkaesten-montageelemente-unterputz-spuelkasten-a-74850.htm

 

Help and assistance please, anybody?

 

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So both of those listed have odour control, first one is with exhaust air. 

 

Check the Geberit product catalogue as all of them should be listed but they look pretty similar 

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