Our technical support team can assist you should you have any questions about your Herrmidifier HST120 Steam humidifier. There are multiple versions of this unit based on the voltage and phase. Your model may be an HST2083120, HST2303120, HST2403120 or HST4803120. 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.