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Doing a bit of renovation and we're moving the kitchen sink. Problem is there are only rainwater soakaways on that side of the house, drains are on opposite side and there are no units in the new kitchen to hide the sink drain pipework behind so it'll be routed under the floor. Due to outside ground level, house floor level, thickness of house wall (3ft+) and general lack of access, running a drain under the kitchen floor with enough fall to get from the sink into the main drain sewer is unfeasible. So, it look like we're going to need a waste water pump.
Couple of questions:
1 - would a normal saniflo-type grey water pump work, or would it be better to have a macerator/pump combined? It's for kitchen sink and dishwasher waste. Any recommendations?
2 - Pipework will be routed under the floor as per shitty diagram:
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I'm guessing there'll be some NRVs required to stop horrible smells creeping back. Should I be putting on in position A, B or both? Again, any recommendations?
Can't see a problem with that.
Fit a trap to the sink waste as normal to stop smells.
Are you sure it can't go in as normal? You would only need about 100mm fall over 5m.
eta: Yes just a saniflo type macerator is all that is required.
Ideally I'd like to have it straight in to main drain, but it's a concrete floor and trying to hack out enough of that so I've got enough space to get a core drill the required 3ft through the house wall, only to pop out the other side below ground level is more than I can bear thinking about. Plus, the outside drain is pretty damned tight up against the house wall (this bit is a very old extension/outhouse conversion and I don't think things were thought through quite so much back in the day) so even if I could manage it I'd be scared of drilling straight through it.
Would you go with 2 NRVs or just one straight after the pump discharge, or is the sink trap and pump/macerator enough?
It's been a long time since i fitted one, but i'm sure it's actually a sanivite that you want for kitchen. They have the NRV built in. The sink trap stops smells coming up from the pump unit and there is a NRV on the pump outlet. I don't think you need any more, i could be wrong though. They have a built in macerator too.
Macerator macerator macerator macerator...
Macerator macerator macerator macerator.
Macerator macerator macerator macerator...
Heeeey!
Macerator,
(That's all.)
Can't you run the drain straight outside behind the sink then wrap pipework around the outside wall?
I can't help thinking that if the pump fails then there is a potential to ruin your kitchen/floor etc very very quickly when all the waste water backs up and runs out somewhere. It would only take a power cut for a short period or a blown fuse to wreak complete havoc.
When you say
<span style="color: #444444; font-size: 12px; background-color: #fbfbfb;">there are no units in the new kitchen to hide the sink drain pipework behind</span>
does that mean there isn't any space behind the units or there isn't actually any units? If there isn't space I would try and make space by spacing the units further out somehow.
Personally I would do anything I could to avoid having a pump, including moving the sink elsewhere to make it easier to put a drain in.
Cheers for the advice folks.
Drain [i]could[/i] be run round outside of the house, but it's a very long and thin house and the run from the sink drain to the main drain would be along the long side from one end to the other and round the corner (about 35m in total) and I doubt there's enough height to get a decent fall. Plus it would look pretty unsightly.
There are no units, just open floor. The other possible route can't be done because the cooker is in the way. Without a complete redesign I can't think how else I can do it. I'm not keen on a pump, but it seems to be the only way at the moment. Future renovations will necessitate the addition a proper drain on this side of the house, but for now it's not cost effective.
If anyone can see a better way, I'm all ears:
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Just a thought, if the pipe failed/blocked under the floor, how would you fix it?
Would it be better to run it through the ceiling void above? Perhaps easier to make a hole and fix a plaster board ceiling that try and lift a finished floor?
Put the sink back over the other side of the room.
The pump WILL fail and it will be a horrible job to fix with potentially a pipe full of nasty stuff in it being held back (hopefully) by a NRV.
the pump WILL fail
I'd considered that and was going to install an isolation valve immediately downstream of the pump as well.
I hadn't considered going up and over. That's sounds like a better idea than laying laminate flooring and hoping it never leaks.
I'd vote for changing the kitchen design too, your solution is only ever going to end 1 way.
Even with the pump, you are going to have a lot of waste water sat in the 5m run of pipe and when the dish water cools, the grease/fat will congeal.
You won't know its failed until its too late so an isolation valve won't be any good, the stinky water will be all over the floor before you are aware of it.
If there wasn't a dishwasher attached I'd maybe go for it but that's an appliance that you leave alone and it will overflow without you being there - washing in the sink you might notice when it blocks.
I assume the cooker is on that RHS wall looking at that diagram. Personally I'd have the sink on the opposite side where your wall D is. Then you have a large prep/cooking/serving out area on the bottom right corner (there isn't much worktop there as it is so moving the sink elsewhere would free up a lot of space there). Then the top left hand corner (where D wall is) is the place where all the dishes go when they have been used - out of the way of the prep/serving out area.
You still have your golden triangle of fridge/cooker/sink there and you could have a little drinks making station end the end of wall D where your kettle/mugs/glasses etc goes handily next to the sink and fridge.
Hope that makes sense.
I used to design kitchens for people BTW if that makes any difference!
I'm not a plumber, but I am an engineer - my Process Engineering colleagues would always avoid a lute (ie, a section that stays full) for any liquid that might carry debris, unless it was essential to have it as a seal, in which case there would always be some kind of accessible catchpot. The pump may increase the velocity to help to flush solids through, but it's a risk. (For clean water, you wouldn't even need a pump, as there's a good head between the sink and the drain, irrespective of the down and up.) Up and over would avoid the lute.
first thing is that type of run is not recommended for a macerator.
You should rise vertically within about 300mm of the unit then fall to the drain.
As Greybeard has said you shouldn't have a section that remains full of water, and being a sink it will be full of fatty water and will block.
You've not got many options if you want to do it properly, probably best to redesign the kitchen if I'm honest. If it was done by a company then they should be shot.