Keep Expansion Tank Cool

      Unless the tank has an inert gas blanket, which is recommended, there is an interface in the expansion tank between the heat transfer fluid and air. This is where oxidation breakdown of the fluid can occur, and the oxidation rate increases exponentially with temperature. This can cause sludge to build up in the tank that can interfere with the operation of level switches and be drawn into the system piping. Most systems have a temperature block or buffer design to prevent high expansion tank temperatures. Check the expansion tank temperature regularly to ensure it is near ambient. If the tank has an inert gas blanket, make sure the nitrogen supply (or other gas) is reliable and maintained at the correct pressure.