Posted by Harold Kestenholz - Hydronic Network on January 08, 2000 at 10:51:48:
In Reply to: Re: Singing Pipes/Hot Water Radiators posted by jtown on January 08, 2000 at 08:53:23:
Cast-iron radiation produces much less resistance to water flow than small-tube baseboard. You may be correct about adjusting the water flow downward to stop the noise which may be from the the pipes or from the free-running impeller of the pump due to little resistance. If you can adjust a balancing valve downward until each loop of pipe has a temperature drop of 20F degrees from the supply to the return, that is the optimum flow rate through the loop. You can see more information on this in the free lessons at
http://www.hydronic.net