cast iron baseboard

bob eck

I have a customer who has a EfM oil fired steel boiler installed 20 years ago or so. He has cast iron baseboard installed and it goes along one wall and then goes to another wall with a inside 90deg turn. The contractor that did the original installation of the cast iron baseboard only used one tapping on the side of the CI baseboard in the inside 90deg turn instead of using both the top and bottom tapping. When the system turns on and the hot water is circulated (160*-180*F) through the CI baseboard there is a loud banging noise. The contractor told me the basement is drywalled and he is trying to find out what the noise is without ripping out all the drywall first. Is this some type of expansion noise? Is this air in the CI baseboard? Is there anything that can be used to take up the expansion and get rid of the noise? Can he use outside reset to lower the water temp going through the CI baseboard. This boiler does have a tankless coil in it. I was wondering if he ran the boiler at 140*-160*F if that would make a difference and stop the banging noise. If he has a steel expansion tank on this system would a amtrol type of expansion tank work?? Thanks for your input

Joe Majercsik

Banging

I have base board heat system. Built in 1957. My question about the banging happens before the pump kicks in. When the gas comes on, it seem like the hot water is
making the pipes swell and the banging seems to be gitting
worse each year. When the pump kicks in and the water starts to flow thru the system it goes away. I let the air
out of the system and have drained the expansion tank to try and help, but nothing I do seems to help. Any way of
getting rid of the noise. I don't think it will hurt anything, it is just annoying.