Jamie998

Pumped Foul Connection

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Right.  Next question!

 

So, if the invert of the manhole I am trying to connect into is 'difficult' to achieve the necessary falls would pumping my foul waste into said manhole be a workable solution?

 

The reason I ask is I am not sure what the velocity of my pumped, mushed up waste would be when it entered the shared manhole.  If the flow rate is vastly different to that of the neighbours 'gravity' connection into said manhole would it lead to blockages should we flush at the same time for example?

 

I may be overthinking this but it is better to do so now before its too late!

 

Likewise, if the two options were either:

 

1.  Gravity connection - difficult to achieve given the tight margins in regards to achieving minimum falls of 1:80           or

2.  Pumped connection - easy to do (if connecting into a shared manhole works!)

 

Which would people recommend?  Having read the forums I have seen that some members are on a pumped system.  Anecdotal evidence seems to suggest it does what is says on the tin and should work fine - if a little more grim than the standard method!

 

I appreciate any & all input.

 

 

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A pump chamber system  can work OK, but they cost a fair bit to both buy and install, and you need space to locate the tank.  The tank has to be sized for the size of house, to allow the foul drains to work for a day or two when the pump fails, to give time for a replacement to be fitted.  It also normally needs an alarm system, so you know if the pump has failed.  We lived in a house with a pumped system and it was OK, but we did inherit a new spare pump with the house (which we didn't need to use, so passed it one when we sold the house).  I lifted the lid on the pump chamber to see how hard it was to change the pump and it looked easy enough.  Not sure it's a job I'd want to do in mid-winter, though.

 

Personally I'd do all you can to avoid having to have a pumped system if you can, as they are, in my view, a last resort solution.

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Changing the pump looks easy, when it is at normal level.

 

Usually by the time you know the pump has failed, the level is way above normal, and you need to get it pumped out somewhere before you can even see the fittings to disconnect the pump.

 

Been there, done that, don't wish to do it again.  If asked again it is a "plumbers job" and I decline.

  • Haha 2

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Ok.  As I suspected but good to have other opinions.  The ridge height is set in stone so I can't raise the house, space I have plenty of.  The crux of the matter is that I need to put a foul connection in now (long story) but as I don't have a foundation in yet I am working backwards from the 'known' which is the manhole and having to 'guesstimate' the depth of my insulated raft (preferred method) in order to ensure I leave myself enough height when laying the pipes so that the rest bend sits in the sub base as per previous thread - but at the same time ensuring I meet minimum falls!

 

I will start another thread in a bit with another question - a nuisance in terms of me starting loads of thread but I want to ensure that the info within stays on point so they can be easily read by future readers who may have similar queries.

 

Thanks

 

Jamie 

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My water table is ridiculously high which has dictated treatment plant height and so has meant high drains. 

My system has all been designed with a 1:80 fall, try this it may gain you some height. 

Are you definitely going insulated slab. 

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19 minutes ago, Russell griffiths said:

My water table is ridiculously high which has dictated treatment plant height and so has meant high drains. 

My system has all been designed with a 1:80 fall, try this it may gain you some height. 

Are you definitely going insulated slab. 

 

Insulated raft is plan A providing that the ground allows it so my drainage needs to work with it - I'm sure it will work out, I have the beginnings of a solution in mind which I will discuss in another thread as it concerns backdrops!!

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I haven't actually Installed it yet but I recently bought and dug the hole for my sewage pumping Station. I got an 800l tank with pump capable of 2" solids and an alarm for £1200 ish (tanks direct if someone wants to check the exact price). The actual connection from the pump to the pipe just uses gravity and an oring so even if it is fully submerged you don't need to get your hands in it. Looks like you just pull the pump up the guide rails and stick a new one on. ( putting the new one on might not be so simple but meh. Iv done worse) 

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I think you need to re address the rest bend thing.

 

I worked my drain levels back from the treatment plant.  I knew how deep that would be and I knew what the finished ground level would be.

 

This resulted in the last drain entry to the house being a bit high.  Okay different foundation system, strip foundations with suspended timber floor, but the rest bend is not fully encased in the concrete of the solum.  But so what. As long as the bend of the rest bend is below FFL I honestly cannot see a problem.

 

So mark it out accurately, and see what level it would be with a 1:80 fall to the main sewer.  If you can avoid a pump station I would.

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I would avoid any sort of mechanical  pumping at all costs --it will only be a headache sometime in future

 

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If you pump you cannot go into a shared drain or inspection chamber directly - you have to go to an intercept chamber first and then run via gravity to the shared sewer connection. 

 

 

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Pumping isn't my preferred option - no moving parts is Plan A.

 

@ProDave I've just modelled it all in Sketchup, to bring my foul run into the neighbours IC I would need to bring the rest bend up into the concrete slab pretty much so I will have to do something at the Inspection Chamber end.

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1 hour ago, PeterW said:

If you pump you cannot go into a shared drain or inspection chamber directly - you have to go to an intercept chamber first and then run via gravity to the shared sewer connection. 

 

 

Plus 1

 

I had to have a pump.  The builder wanted to put it straight to a manhole.  Yorkshire water said no - As Peter says - had to pump up higher - beyond the manhole and have a new inspection chamber with gravity feed into existing sewer.

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1 minute ago, Hecateh said:

Plus 1

 

I had to have a pump.  The builder wanted to put it straight to a manhole.  Yorkshire water said no - As Peter says - had to pump up higher - beyond the manhole and have a new inspection chamber with gravity feed into existing sewer.

 

Adding more inspection chambers is what I want to avoid.  My plot was the neighbours garden, there is now a driveway owned by her which I have rights of access for anything and everything I could possibly need over it.  There are already two fugly manholes in the drive at the front of her house bordering the drive - we don't need a third!

 

I'm on a mission to minimalize/hide manholes where I can.

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My plot was my own garden.

Where I thought I would be able to get directly into a sewer, the connection is in a neighbour's garden and under a lean to extension. So had to rethink. 

 

There was no way Yorkshire water would do anything other than have a pump and have a fugly inspection chamber in the middle of my drive.  If there was any other way round it I would have taken it.  Cost me more (like everything else did) and I have the concern of a possible pump failure.  

 

Along with having to pay 13k for my electric supply and my pathetic builder, my project came in at 50% over budget.  

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@Jamie998 What is your height deficit in terms of achieving a designed 1:80 fall?

 

Is your most distant source of drainage upstairs or ground floor?

 

Can you hook into your neighbour's foul drain closer to the mains sewer and thus deeper?

 

 

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