False hope for radiator

Fizz

Found that lateral from run-out to riser was pitched wrong, corrected it , heard rush of some water.  StIll no heat to radiator.  Gets to valve or sometimes not quite.  Wondering if it's a balance problem?

ChrisJ

Rush of water

Are you sure that horizontal section is pitched enough?  You need an inch per 10 feet if I remember correctly assuming its connected to the main via a 45.  For a 90 degree its something like an inch per foot.



I have a runout that after a local plumber replaced the pipe it was pitched bad enough it wouldn't heat, ever.  He used iron pipe and did a good job but botched that part.  I think its because the oirignal had a hole, probably drilled in it to let condensate drain and he assumed that part was good when he put it back together.



Either way, with a little more pitch it worked, but banged on start up and worked slow.  Condensate laying the pipe eats steam and under severe cases will eat enough to cause severe banging.

Sure, it could be a balancing issue as well, my system if I vent my short main fast and vent the 3 radiators on it fast it causes all kinds of issues for the other main.  Shut off two or three radiators by flipping the vents and see what it does.  If you get a ton of steam with zero banging then I'd go with balancing issue and slow up other radiators.