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Kitchen sink: Bottle trap or P/S trap?

Discussion in 'Plumbing and Central Heating' started by TofuSpaceship, 17 Mar 2020.

  1. TofuSpaceship

    TofuSpaceship

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    in the process of fitting new plumbing for the kitchen waste.

    I read quite some opinions online of people who wouldn't fit bottle traps under a kitchen sink, but rather P trap or S trap. They claimed it fills up with gunk very quickly.

    I am not one of those people that uses a sink as an organic bin.
    Plus, I would prefer to fit a bottle trap because is more compact and once in a while it can be opened and be properly cleaned, something that will never happen with a S trap.

    Am I mad or am I missing something out?
    Thanks!
     
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  3. Madrab

    Madrab

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    Not at all, you can use a bottle trap if you wish. They are more restricted to flow through than an S or P trap and as such can catch more gunk and clog up more quickly but if you're happy knowing that you may need to clear it more regularly, then no reason not to use them.
     
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  4. Nige F

    Nige F

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    A bottle trap will need a few inches under it to unscrew + clear the bottle from the dip tube. A S or P needs no clearance under. So if you've got a shelf............;)
     
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  5. TofuSpaceship

    TofuSpaceship

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    @Nige F
    good observation.
    You guys are making me think. Of course deciding on the shelves is the missus domain, but surely the more clearance we have under the sink the better it is.
    As I'd like to have access to the trap to clean it once in a while, that being a bottle or a P/S, I thought I could use compression fittings and have my P trap.

    I could then use an air admittance valve on top of the stack, behind the sink cupboard, couldn't I?

    EDIT: Or I could use a McAlpine SWIVEL P TRAP WHITE 40MM, just seen it has a little AAV embedded. We live in a wonderful world, out there there is a part for every need!

    EDIT2: is there a maximum distance that needs to be respected between the sink drain and the actual trap? I am thinking of coming straight down the sink bowls with a bend directed towards the back of the unit, then a bend down to a little stack where DW and WM will connect and then down from here going into a P trap (with AAV embedded) which is then connected to the stack at the back of the unit, which takes us to the bend that connects the bit of horizontal pipe going across the wall.

    I tried to make a drawing but I am no good in drawing in 3D!
     
    Last edited: 18 Mar 2020
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  7. Hugh Jaleak

    Hugh Jaleak

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    Personally cant stand bottle traps, flow is dissipated around the bottle and allows gunk to build up, whereas a 'P' or 'S' trap will always be full flow, and provided the sink is kept clean and regular maintenance with boiling water and/or soda crystals is carried out to prevent build up of crud, it'll be rare there's an issue. Also bear in mind, each time you undo a bottle trap there's a risk the large sealing O ring will fail and you'll either end up replacing that or the trap....

    Trap must be immediately after the sink, trying to put it further along will just lead to issues will gunk in the pipework, (some is unavoidable), releasing a stink back into the room. If Dishwasher and washing machine need to connect further away, look at providing a separate standpipe for these and fit a McAlpine twin connector on the top to accept both drain hoses. https://mcalpineplumbing.com/traps/domestic-appliance-traps-accessories/v33wm-twin-connector
     
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  8. CBW

    CBW

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    You came to the right place for advice ;)
     
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  9. TofuSpaceship

    TofuSpaceship

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    I actually already own one of those McAlpine connectors, it was used in the previous setup for WM and boiler condense to discharge in the drain stack.
    (actually, more on the boiler condense later on..)

    I hear you about having the trap as close as possible to the sink drain, however, if I were to have the DW and WM connection further away, shouldn't I have a trap after these, otherwise foul smells can come up through the WM and DW???

    About the boiler condense, as we are speaking plumbing anyway. When the boilerman came round to fit the boiler back up a month or two ago, he left behind a 21.5mm overflow waste pipe as he said that that is the pipe to be used for condense - which I don't disagree with.
    However, I have only now tried connecting that 21.5mm overflow waste pipe to the end of the boiler's condense grey drain hose (exactly the same hose as a WM's drain hose) and the dark grey rubber collar of said hose visibly expand when I insert the white overflow pipe. Is this a proper connection? Should I run it all in grey WM-style drain hose instead?
    Thanks!
     
  10. Hugh Jaleak

    Hugh Jaleak

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    You have several choices connecting a washing machine and/or dishwasher to the waste, basically, either connect at the sink position, using an appropriate trap, or if connecting further away, you need to use a standpipe, https://www.screwfix.com/p/floplast-washing-machine-trap-white-40mm/18640

    Self cutting waste connectors are available to join straight into the waste pipe but these are awful things and no real Plumber would use one.

    Condensate drain from the boiler is another issue. This can constitute part for the flue system and should be installed by the Engineer who fits the boiler, quite why it's been left like that I dont know and could be a bit naughty. Will leave it for the Gas Trained People to comment further.
     
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