Central heating - available differential pressure

[TSN79]

I'm reading up on the use of the valve seen in the link below. On page page 5-6 there is the mentioning of available differential pressure. I struggle with understanding what that means exactly. Say I have a set of main supply/return pipes along a building, with some branches along the way connecting this and that. At the far end the main pipes are capped - being available if something needs to be connected in the future. How would I go about finding what the available differential pressure is at this end of the system?

https://imisharepointstorage.blob.c...nternational/PDF_low/STAP_DN15-50_EN_MAIN.pdf

 

[CWatters]

If I've understood correctly you just measure the pressure in each pipe (eg relative to atmospheric pressure) and subtract one reading from the other.

 

[anorlunda]

Amplifying what @CWatters said, you have to plumb in some pressure gauges.