What is the blank at the ball cock for?

[Nwalky]

Been a plumber for many years and nine times out of ten when changing a ball cock at a tank there is a tee rather than a bend, the tee then has a blank at the end. Anyone know why this is? I am always just taking the tee out and putting a bend on because it is simpler but the more I see this the more I question the reasoning behind it.

I'm intrigued to find out if anyone knows of the logic behind this,

Cheers

 

[steadyon]

As a complete guess, feed to F&E tank subsequently removed.

 

[Nwalky]

As a complete guess, feed to F&E tank subsequently removed.

I know what you mean, but there was never an F&E tank in as it is a dry electric system that is in place. It's really strange because I have seen it a lot in different jobs and I can't understand why it would ever be there, someone will hopefully give a belter of an answer as to why it was done haha

 

[Ric2013]

In the old days, it was apparently customary to allow an air pocket as a shock absorber to prevent ballcock murmur. Eventually the water will absorb the air and the air pocket disappears. Should the ballcock start to make a noise, all that would be required would be to isolate at the stopcock and draw enough stored water to open the valve - this would replenish the air pocket.

I would imagine that that is almost certainly what you have in your photo.

To comply with the modern Water Regulations, such dead legs are no longer permitted as they allegedly allow bacteria to breed, but you could use an expensive mini shock arrester/expansion vessel instead.

 

[Nwalky]

In the old days, it was apparently customary to allow an air pocket as a shock absorber to prevent ballcock murmur. Eventually the water will absorb the air and the air pocket disappears. Should the ballcock start to make a noise, all that would be required would be to isolate at the stopcock and draw enough stored water to open the valve - this would replenish the air pocket.

I would imagine that that is almost certainly what you have in your photo.

To comply with the modern Water Regulations, such dead legs are no longer permitted as they allegedly allow bacteria to breed, but you could use an expensive mini shock arrester/expansion vessel instead.

Ding ding ding, we have a winner haha nice one mate, it has always had me wondering. Glad I have an answer to this after all these years wondering about them, thanks