First time I have scanned hot water system radiators, appears to be blockage at the top 1/3 of the two largest ones. Any thoughts on the cause, air lock or corrosion?
John,
I find this situation quite a bit, especially the last image showing half the radiator heating up. I always recommend a Plumber to maintain the boiler and bleed the radiators.
We don’t see them things out in Calif any more. Brings back to old days as a kid back in Ohio.
Nice find.
Best
Ron
Probably just air bound.
There should be an air bleed fitting near the top of the cast iron radiator.
http://www.primo.ie/catalog%202/Insutry/plumming/plumb22.gif