In flats, where does cold water tank overflow pipe drain to

[hubner]

In a house, the cold water tank in the loft has the overflow pipe going through a hole in an external wall, so if the ball valve which prevents the tank from over filling stops working, water will drain out through the overflow pipe instead of leaking all over the floor.

What about in a block of flats where the tank is a cupboard in each flat? I heard that the overflow pipe should connect to the bath drain pipe. And why would a tradesman not connect/reconnect the overflow pipe, is it incompetence or malice?

[chrisbainbridge]

I cannot answer much of your question.  I was told that all overflows now have to be visible to save wasting water

[DaveReading]

Don't all modern toilet syphons have to have an internal overflow, making the external one unnecessary ?

[ian]

Ours do, they overflow into the bowl. I thought that was normal. The only overflow we have is the condensation pipe from the boiler.

[Diver300]

The overflow connects to the drain via one of these:-
https://www.wolseley.co.uk/product/mcalpine-tun-4-one-piece-tundish/
That allows overflows to be visible, and prevents pressure building up even if the drain is blocked.

The one that I saw has a non-return valve so that smells don't come from the drain.

[Sergeant Pluck]

Ours do, they overflow into the bowl. I thought that was normal. The only overflow we have is the condensation pipe from the boiler.

And even those need to be plumbed in to an indoor drain these days. Remember the great boiler overflow pipe freeze a couple of years ago?

[nuttycyclist]

A few months ago my toilet inlet valve failed.  This resulted in the toilet never actually stopping flushing.

I added anger to my normal morning routine and I told Mrs Nutty who informed me she knew all about it as faecesbook said we had a water shortage outage in our area.  I couldn't equate "water shortage and mains pressure drop" to the situation downstairs where the water was running into the toilet bowl without stopping.

I explained that I'd be turning the water to the house off to resolve it, so she'd better get out of bed for her mornining shower before the school run, as otherwise she wouldn't get a shower.  As apparently there was "no water, according to farcebook", she did the school run pre-shower and I turned the water off, cleaned the flake of limescale from the valve, and restored service by the time she got home and without need to cycle to nearest supplier of replacement parts.

[hellymedic]

Ours do, they overflow into the bowl. I thought that was normal. The only overflow we have is the condensation pipe from the boiler.

And even those need to be plumbed in to an indoor drain these days. Remember the great boiler overflow pipe freeze a couple of years ago?

Do they? When dd that start? Our boiler was installed in 2016 and has an external condensate pipe.

This froze in 2018 of course.

We've never been offered internal plumbing.

[Sergeant Pluck]

2018.

https://hhic.org.uk/uploads/5BD6D5A19764A.pdf

"Where an installer is fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal “gravity discharge point” such as an internal soil stack (preferred method), internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste."

[lissotriton]

Do many flats have cold water tanks nowadays? Aren't they connected direct to the mains supply?

[Diver300]

Do many flats have cold water tanks nowadays? Aren't they connected direct to the mains supply?

Yes, but there may be a tank and expansion vessel, and that needs a pressure relief valve of some sort, and the outlet from that has to go somewhere.

[hubner]

In the OP's example (block of flats), the mains cold water (the water going into the flat) goes to the kitchen cold tap but also goes into a cold water tank. The water tank then supplies cold water to the bathroom basin, shower and toilet.

Hot water is from a central boiler, and goes into a smaller padded tank under the cold water tank. Which then go through a water pump and supplies hot water to the kitchen and bathroom.

I think.

[Ashaman42]

2018.

https://hhic.org.uk/uploads/5BD6D5A19764A.pdf

"Where an installer is fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal “gravity discharge point” such as an internal soil stack (preferred method), internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste."

And here's me with a new boiler fitted in 2019. With an external condensate pipe.

Damnit.

[tatanab]

"Where an installer is fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal “gravity discharge point” such as an internal soil stack (preferred method), internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste."

Even that is not perfect.  Mine discharges into the kitchen sink waste because there was no sensible place to discharge externally (not allowed to discharge onto the ground).  About 10 years ago we had a very cold winter and the kitchen drain through the wall froze solid.  Imagine the little bit of condensate coming along, feeling the outside air and saying "I'm not going out there" and forming a log jam instead.  A solid plug of ice through the wall.  As a consequence, if the temperature is that low (several degrees below freezing) I disconnect the connection under the sink and let the condensate drip into a bucket.

[hellymedic]

2018.
https://hhic.org.uk/uploads/5BD6D5A19764A.pdf
"Where an installer is fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal “gravity discharge point” such as an internal soil stack (preferred method), internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste."

So I missed out, buggrit.
And suffered.

Freezing condensate must have been a known ussue by 2016 but it took until The Beast from the East for me to realise...

[aidan.f]

'should' not 'must' gives installers wiggle room and often if it's easier and cheaper...

[Kim]

Shirley the correct answer to "In flats, where does the $whatever drain to?" is always "The flat below."

[hellymedic]

'should' not 'must' gives installers wiggle room and often if it's easier and cheaper...

I am still VERY ANGRY about being let down by my brand new plumbing, within two years of installation.

It was not cheap.

I miss my cold water tank and my hot water cylinder.

I resent waiting AGES for 'hot' water in my kichen.

[Mike J]

Ours goes into the bath

[rogerzilla]

2018.
https://hhic.org.uk/uploads/5BD6D5A19764A.pdf
"Where an installer is fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal “gravity discharge point” such as an internal soil stack (preferred method), internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste."

So I missed out, buggrit.
And suffered.

Freezing condensate must have been a known ussue by 2016 but it took until The Beast from the East for me to realise...

Mine goes into a drainpipe outside.  I've never known it freeze while I've been here, but I don't use the CH much.  Apparently the previous nonagenarian owner had problems, but she used to run it full blast 24/7.

[hellymedic]

We run our place warm. D feels the cold more than I do. The boiler seemed to struggle when it was really cold.

Freezing condensate pipe REALLY upset me though!