Hot water cylinder number of pipes?

[Deleted member 96797]

Hot water cylinder in airing cupboard has 5 pipes entering it. 2 are obvious and are the feed and return from boiler. Another 2 are obvious and are the cold water feed and hot out. There is a 5 th that enters the cylinder just above where the boiler feed enters. It has a manual shut off valve. Please advise what this pipe is for and whether it is important to have open or closed.
Thank you

 

[Chuck]

Please advise what this pipe is for and whether it is important to have open or closed.

We's need a photo or precise model number to be sure, but that sounds like a secondary circulation return. See, for example:

Secondary Circulation to ensure hot water is available immediately the tap is turned on.

 

[jtsplumbing]

Could be a feed for a shower, !!

 

[Deleted member 96797]

Thanks everyone. A quick test (turn on shower in bathroom) and the pipe got hot. Fairly conclusive. It’s a shower feed.

Cheers