We stock every part for the Herrmidifier MDSI Series Steam humidifier ever made. Our technical support team can assist you should you have any questions about your Herrmidifier MDSI Steam humidifier. Order from the source of Herrmidifier Steam humidifier tanks and parts just like the contractors do. Remember to replace your Herrmidifier Steam tank at least once per year for optimal operation. Most Herrmidifier Steam humidifiers will bring up a warning sign when the steam tank fails. Unfortunately you must view the unit periodically to know when it is time. We recommend you replace the steam tank at least once per year for residential applications and more often for commercial and industrial humidification needs.