I’ve attached a document “The Challenge of correct flow sensor installation with respect to flow disturbances” I believe I got this from Glynn which gives remomended min distance for a variety of locations. I’ve given you a snapshot of that table as well as the whole document.
The challenge of correct flow sensor installation with respect to flow disturbances.pdf (517.7 KB)
The biggest problem most of us have faced is purging the air from the system as this leads to erroneous flow readings. Trapped air and location are the two hurdles to overcome.