Installing water softener - drainage question

itssmallstuff

So, I want to plumb in the waste from watersoftner into my existing sink waste..

This is a utility room sink, doesn't get used much at all. This sink has washing machine drain attached already.

How best can I accommodate waste from watersoftner too please?

itssmallstuff

Existing waste pipe with washing machine drain connection

itssmallstuff

That's from manufacturers of water softener

Ebe_Scrooge

The simplest way would be to replace the section of pipe that has the drain spigot with one that has 2 spigots.  Or replace one of the other sections with a section that has a spigot attached.  Those plastic drainage systems are a doddle to work with - each section will just unscrew by hand, no special tools needed, and you can add in whatever extra bits you need.

I'd start by removing the U-bend at the bottom - put a bowl underneath to catch the water that will be lying in it.  That'll mean you won't get an unexpected escape of water when you come to remove whatever other bits you decide to swap.  While you've got it off, may as well take the opportunity to give it a clean out (in a different sink to the one you've just removed it from!).

You can buy new parts/sections for just a few quid from anywhere - online, DIY sheds, Screwfix, etc. etc.  Just measure the existing pipe that you want to replace (length and diameter) and make sure you buy the correct-sized replacement (they all come in a range of standard sizes, so it should be very easy to find a like-for-like replacement).

When you replace a section, you'll see that there's a rubber washer in the screw-on connector.  Just take a few moments to make sure everything is nice and clean when you re-assemble, to make sure you get a good watertight seal.  Personally, I put a little smear of Vaseline on the washer and the threads, just to make sure it's lubricated and to help make it watertight, but that's not really necessary - just belt & braces really, probably overkill!  As long as it's clean, everything should slide/screw together easily. Other than that, it should be an easy-peasy job to install a new section of pipe to suit your needs.

itssmallstuff

Ebe_Scrooge said:

The simplest way would be to replace the section of pipe that has the drain spigot with one that has 2 spigots.  Or replace one of the other sections with a section that has a spigot attached.  Those plastic drainage systems are a doddle to work with - each section will just unscrew by hand, no special tools needed, and you can add in whatever extra bits you need.

I'd start by removing the U-bend at the bottom - put a bowl underneath to catch the water that will be lying in it.  That'll mean you won't get an unexpected escape of water when you come to remove whatever other bits you decide to swap.  While you've got it off, may as well take the opportunity to give it a clean out (in a different sink to the one you've just removed it from!).

You can buy new parts/sections for just a few quid from anywhere - online, DIY sheds, Screwfix, etc. etc.  Just measure the existing pipe that you want to replace (length and diameter) and make sure you buy the correct-sized replacement (they all come in a range of standard sizes, so it should be very easy to find a like-for-like replacement).

When you replace a section, you'll see that there's a rubber washer in the screw-on connector.  Just take a few moments to make sure everything is nice and clean when you re-assemble, to make sure you get a good watertight seal.  Personally, I put a little smear of Vaseline on the washer and the threads, just to make sure it's lubricated and to help make it watertight, but that's not really necessary - just belt & braces really, probably overkill!  As long as it's clean, everything should slide/screw together easily. Other than that, it should be an easy-peasy job to install a new section of pipe to suit your needs.

Thank you so very much. This gives me the confidence to crack on with it.

I'm thinking of replacing the part just above the U bend with something that has 2 drain connectors.. what I'm not sure of is if the drain pipe from watersoftner connect to it due to size difference... 

The watersoftner drain pipe is 1/2" without any special end like the washing machine to help slide on..

itssmallstuff

Ebe_Scrooge said:

The simplest way would be to replace the section of pipe that has the drain spigot with one that has 2 spigots.  Or replace one of the other sections with a section that has a spigot attached.  Those plastic drainage systems are a doddle to work with - each section will just unscrew by hand, no special tools needed, and you can add in whatever extra bits you need.

I'd start by removing the U-bend at the bottom - put a bowl underneath to catch the water that will be lying in it.  That'll mean you won't get an unexpected escape of water when you come to remove whatever other bits you decide to swap.  While you've got it off, may as well take the opportunity to give it a clean out (in a different sink to the one you've just removed it from!).

You can buy new parts/sections for just a few quid from anywhere - online, DIY sheds, Screwfix, etc. etc.  Just measure the existing pipe that you want to replace (length and diameter) and make sure you buy the correct-sized replacement (they all come in a range of standard sizes, so it should be very easy to find a like-for-like replacement).

When you replace a section, you'll see that there's a rubber washer in the screw-on connector.  Just take a few moments to make sure everything is nice and clean when you re-assemble, to make sure you get a good watertight seal.  Personally, I put a little smear of Vaseline on the washer and the threads, just to make sure it's lubricated and to help make it watertight, but that's not really necessary - just belt & braces really, probably overkill!  As long as it's clean, everything should slide/screw together easily. Other than that, it should be an easy-peasy job to install a new section of pipe to suit your needs.

How about this one

https://www.screwfix.com/p/mcalpine-twin-hose-connector-40mm/206HR?tc=IC2&ds_kid=92700055281954514&ds_rl=1249404&gclid=Cj0KCQjwzLCVBhD3ARIsAPKYTcR-LKopxKq8m_NU8hQsCmRnD9Cg9N6c-fiiXoVIC0yAby50Sl77dvYaAhNPEALw_wcB&gclsrc=aw.ds

This has an inbuilt air gap which is good, but can't make out where will the sink waste go, as it has just 1 big opening as opposed to two...

Section62

itssmallstuff said:

Ebe_Scrooge said:

The simplest way would be to replace the section of pipe that has the drain spigot with one that has 2 spigots.....

Thank you so very much. This gives me the confidence to crack on with it.

I'm thinking of replacing the part just above the U bend with something that has 2 drain connectors.. what I'm not sure of is if the drain pipe from watersoftner connect to it due to size difference... 

The watersoftner drain pipe is 1/2" without any special end like the washing machine to help slide on..

I wouldn't ever install a water softener that way.

If you get a blockage in the drain it would be possible for polluted water to enter the water softener drain pipe, and potentially get into the ion exchange tank.  At best this might kill the catalyst, at worst you could be drinking water contaminated with whatever has gone into the sink and/or is living in the drains.

There's a reason why the diagram you've posted shows an 'air break' between the softener drain pipe and the drain it is discharging into.  This ensures that contaminated water cannot reach the 'clean' side of the softener via backflow.

It is probably also the reason why your water softener isn't fitted with a washing machine style drain connector - i.e. discouraging people from plumbing it in the same way you would a washing machine or dishwasher.

I would always fit a water softener using a separate standpipe as per the diagram - ideally with a completely separate run of 40mm pipe until it reaches either a foul-water gully or a pipe of 110mm diameter or greater. That way the risk of blockages resulting in backflow into the softener is minimised as much as possible.

itssmallstuff

Section62 said:

itssmallstuff said:

Ebe_Scrooge said:

The simplest way would be to replace the section of pipe that has the drain spigot with one that has 2 spigots.....

Thank you so very much. This gives me the confidence to crack on with it.

I'm thinking of replacing the part just above the U bend with something that has 2 drain connectors.. what I'm not sure of is if the drain pipe from watersoftner connect to it due to size difference... 

The watersoftner drain pipe is 1/2" without any special end like the washing machine to help slide on..

I wouldn't ever install a water softener that way.

If you get a blockage in the drain it would be possible for polluted water to enter the water softener drain pipe, and potentially get into the ion exchange tank.  At best this might kill the catalyst, at worst you could be drinking water contaminated with whatever has gone into the sink and/or is living in the drains.

There's a reason why the diagram you've posted shows an 'air break' between the softener drain pipe and the drain it is discharging into.  This ensures that contaminated water cannot reach the 'clean' side of the softener via backflow.

It is probably also the reason why your water softener isn't fitted with a washing machine style drain connector - i.e. discouraging people from plumbing it in the same way you would a washing machine or dishwasher.

I would always fit a water softener using a separate standpipe as per the diagram - ideally with a completely separate run of 40mm pipe until it reaches either a foul-water gully or a pipe of 110mm diameter or greater. That way the risk of blockages resulting in backflow into the softener is minimised as much as possible.

Fair point.
The wall next to the watersoftner is an external wall and just outside is the drainage. It's entirely possible to drill another hole and keep this entirely separate. I was going to make a hole anyways for the overflow.

There are connections available with built in air gaps..like one I posted in my earlier comment. Are they any better?  

On a separate note, what exactly does the air gap do? Would the water running backwards sprout out instead of getting into appliance drain hose?

Section62

itssmallstuff said:

Fair point.
The wall next to the watersoftner is an external wall and just outside is the drainage. It's entirely possible to drill another hole and keep this entirely separate. I was going to make a hole anyways for the overflow.

The pipe through the wall should really be 40mm waste pipe, with a trap and standpipe on the inside.  If you take the smaller diameter flexible drain pipe through the wall there is a risk of water in it freezing during cold weather.  The pipe should be trapped between the internal and external ends to stop insects etc from getting into the house (and/or water supply).

itssmallstuff said:

There are connections available with built in air gaps..like one I posted in my earlier comment. Are they any better?

The fitting you linked to isn't designed for use with a sink. It goes on the top of a standpipe to allow two drain hoses to be connected, and rather more neatly and reliably than just poking the drain hose into the top of the standpipe.  If the drain hose is installed carefully then you don't need a fitting like that one. (i.e. cut to the correct length and clipped to the wall)

itssmallstuff said:

On a separate note, what exactly does the air gap do? Would the water running backwards sprout out instead of getting into appliance drain hose?

The air gap prevents syphonic action - having a point open to the air means that if backflow conditions exist in the appliance, the drain hose will draw in air rather than contaminated water.

Being open to the air means that if there is a blockage in the drain the water may overflow or spurt out, but that is a side effect rather than the intended method of operation.