Hydronic water heating system makes banging noise during heating cycle
I have a older hydronic hot water heating system (installed in 1976) that circulates the water once the water temperature get to the appropriate temperature and continues to circulate and heat the water as long as the thermostat requests heat. I have 4 zone valves and 4 thermostats. My problem is that during the heating process when the burners are on there is a banging or hammering noise that occurs from the boiler during the heating cycle. It seems to occur even when all zones are shut off and not circulating. The pressure in the line is about 10-12 psi and the heating cycle occurs from around 160 to 180 degrees F. I have bled the lines of the air but the noise is still occurs. Any causes for the noise and what are the solutions to solve this situation? Please advise.
Last edited by Jtrevis; 12-28-2007 at 02:23 AM.
Reason: word changes