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Any plumbers about? We had a new water softener installed yesterday. All working well and very happy with the work done. Just curious about the air gap connection for the waste water cycles.
Is it really necessary?
Our last one didn't have one.
Just wondering what happens if the 20mm waste pipe gets blocks/frozen outside; what stopes the water backing up and out of the air gap then going all over the floor?
Can I add an overflow to the air gap to prevent this?
I'm not familiar with water softeners, but the air gap is presumably to stop backflow of unwholesome water into the mains water supply. Scottish Water have certainly tightened up on backflow requirements in the ~15 years I've been working on building design, so it wouldn't surprise me if your previous model didn't have an air gap, or perhaps it didn't have a backwash/waste water cycle?
If you plumb the air gap via an overflow I suspect there will be a requirement that any discharge is immediately visible so you can rectify a problem, so you might need a certain type of tundish between the air gap and any plumbed pipework you are using to collect it.
Somebody more familiar with water softeners might appear to debunk all of the above though!
Washing machines and dishwashers are often plumbed into an upright standpipe that isn't sealed (the alternative being dedicated spigots on the sink waste).
You see it quite a bit including on toilet cistern overflows...leaks should be visible and prevent backflow.
The water softener has a non return valve to prevent backflow anyway.
Just concerned about water damage to the floor with the airgap.
A check valve is not a suitable means of prevention of contamination from the category of fluid found in waste water systems.
All basin, sink and bath taps incorporate an air gap (unless you have a pull out spray that usually doesn’t conform!)
It shouldn't ever freeze, the outflow from the softener is briny salt solution isn't it?
Presumably it's installed in a kitchen or utility, surely the floor can cope with getting wet occasionally? I think it's more likely a joint in your mains pressure plumbing would leak, than your overflow..overflowing? And that would be harder to spot
Ours just has an upright pipe (with a Hepvo waterless trap) and a flexible pipe from the water softener poked into it. The same approach as often used for a washing machine or dryer.
What are you concerned it might freeze?
The waste from the softener is a 10mm flexible pipe going into the airgap, then into a 20mm pvc pipe that goes out the wall and runs along for about 3m outside. If that 20mm pipe freezes outside, the airgap will fill up and overflow indoors.
I've had condensate pipes freeze from a boiler in the past so know it can happen.
That is true. The solution would be not to have the waste pipe running where it could freeze (ie an internal drain) but I'm guessing that's not possible.
Our water softener is not 'sealed' - ie the lid where you put the salt in just sits there. Â Theres an overflow (that goes to the same pipe as the regeneration 'waste'. Â If the pipe froze and the overflow and waste were sealed I'm pretty sure our unit would then overflow through the salt door and flood the house.
I think it's extremely low risk - condensate pipes have a trickle running through them that can freeze and build up.  The waste pipe on this is going to have  a fairly high volume of very salty water running through it (which isn't going to freeze quickly when the unit regenerates (and then presumably clean water to flush afterwards).  But a 20mm pipe seems a bit small - if you wanted to reduce the risk swapping that for a 35mm waste pipe would do it.