A Stop Tap question ...

[Ray1000]

This is more out of curiosity than a problem ...

In our 1964 bungalow when you turn off the main stop tap the cold water to the sink taps stops immediately.

In my son's 1998 two storey house after struggling to turn the under sink stop tap off to work on an upstairs toilet cistern, the kitchen sink tap continued to run albeit slowly. Assuming the water was draining down from upstairs I had a look at the cistern and solved the problem without opening anything up.

After turning the stop tap back on it took a while for the pipes upstairs to fill up and the air to expel.

Later wondering if it was the indoor stop tap not sealing, I turned the water off on the pavement with the same result.

I'm assuming if we were desperate to have the water off it would eventually drain off completely at the downstairs kitchen sink.

But what is it about the two systems that allows it to hang in the pipes at our house but not at my sons?

It is as though there is an "automatic bleed valve" in new houses letting the air into the emptying pipes.

Thank you
Ray

 

[Harry Bloomfield]

It's a simple matter, of whether air can get in, to replace water which runs out. If air has no way to get in, the pipes will retain the water, but flush a toilet, turn an upstairs tap on, the water will drain via the lowest open tap.

 

[Ray1000]

I understand Harry,
Seemingly without anything open other than the kitchen tap water drains from the upstairs ... I'm wondering where the air might be getting in?

 

[Harry Bloomfield]

I understand Harry,
Seemingly without anything open other than the kitchen tap water drains from the upstairs ... I'm wondering where the air might be getting in?

It could be entering, from the one tap you do open - it depends upon the layout of the pipes.

 

[Ray1000]

Thank you Harry
It’s aggravating that it looks exactly the same as it would if neither of the stop taps were sealing properly.
It’s probably made worse for having 5 sinks and 3 toilets.
Ray

 

[Ray1000]

Just one more question … is it more common to initially hang in the pipes or to empty the system?