Riser blockage or pressure issue ?

PTTG40

Since Ive taken everyone advise to lower boiler pressure in my residential 3 story home, some of the banging has lessened which is great. On eo thing I noticed was that the riser to the third floor that did bang alot right at this elbow in the photo. Its about 15 feet from the main. The foot before the elbow is hot and right after the elbow the pipe stays pretty cool, sometimes warm. But thats where it bangs so that obvious. 

Do you think it is a clog, water residue that needs to be let out or some other problem? Thank you

Jamie Hall

What's the pitch

on that horizontal pipe heading away from the camera?  It's got to be pitched back pretty aggressively; if it's level or even slightly pitched, it's going to bang.



Obviously at the same time, though -- check the pitch on the going to the right.  It has to have a pretty aggressive pitch, too.



Either one could easily be your problem -- and I observe that increasing the pitch on one is likely to flatten the other...



Cheers!