Expansions tanks are an essential part of your hydronic heating system, they employ a diaphragm in the center of the tank creating a pressurized pocket of air in the bottom of the tank that allows the tank to absorb excess pressure generated from the expansion of the water in your heating system.If your expansion tank stops working properly it can cause several problems in your heating system from banging in the pipes to leaks and relief valve blow offs. Call us today to have your expansion tank checked.