ESS Emergency Shower Water Heater


The ESS water heater is packaged with the Therm-O-Mix®/WWM specifically designed, tested, and proven in emergency safety shower/face/eyewash applications. When you specify and install a ThermOmegaTech® tempered water system, you can be confident that it will be a safe and dependable source of tepid water for an emergency drench system.

Operation – How the Safety Shower Tempered Water System Operates

Packaged with the ESS is a triple-redundant thermostatic valve explicitly designed for emergency safety shower/face/eyewash applications. The Therm-O-Mix®/WWM is factory mounted and piped to the water heater. After the water flow is activated at the emergency station, the outlet water temperature from the ESS will be maintained at 85°F tepid temperature.

The ESS Emergency Shower Water Heater can achieve the high-volume demand required for a safety drench system by mixing the 170°F water in the tank with incoming cold water. The mixing valve of our tempered water system meets OSHA and ANSI requirements and can provide a constant 85°F output regardless of inlet pressure and temperature variations. The temperature is factory set, making the valve tamper-proof.

The water temperature is not warm enough to open skin pores and not cold enough to deter usage. The valve can provide a full range of flows from 0.4 GPM for an eyewash to the combined 23 GPM flow for a simultaneous demand for a shower, eyewash, and face wash system.

For two-shower operation, the minimum water pressure needs to be 60 PSIG to satisfy ANSI Z358.1 pressure spec of 30 PSIG at the shower head. If longer than 20ft runs from the heater to shower station are needed, the water pressure needs to be 68 PSIG for up to 50ft and 81 PSIG for up to 100ft.

Safety Features

The Therm-O-Mix®/WWM incorporates a pressure-sensing controller with a thermal actuator that senses the water pressure on the hot and cold water inlet connections. If the hot water pressure is absent, the actuator overrides the mixing valve, allowing cold water flow. If no cold-water pressure is available at the mixing valve inlet, the hot water port will close to prevent overheated water from exiting the mixing valve.

The valve also includes a safety override feature that continuously senses the final mixed water temperature. If the final water temperature is overheated, the valve automatically closes the hot water port and fully opens the cold water port. In any of these fault conditions, the ESS will continue providing a full flow of water per the ANSI standard with no additional pressure drop.

Typical Applications

The ESS emergency shower water heater packaged with the WWM water/water mixing valve is used for emergency safety shower and face/eyewash stations in manufacturing, food production, chemical, pharmaceutical, petrochemical, and other facilities where personnel can be exposed to hazardous or corrosive materials.

ThermOmegaTech® offers a range of tepid water systems for safety showers to meet your needs. From our steam and water mixing Therm-O-Mix® Station, hot and cold water mixing Therm-O-Mix®/WWM valve, or our ESS tepid water heater, your employees will always have access to safe, reliable, and comfortable showers when they need them most. Contact us to make our safety shower tempered water system part of your workspace or facility.

Design Features

  • Factory packaged with the Therm-O-Mix Station®/WWM
  • All electrical operating controls are factory selected and wired to ensure reliable operation
  • ½” Hydrastone cement lining provides tank longevity
  • Fully insulated with 3″ thick polyurethane foam to minimize standby heat loss
  • Copper-silicon alloy tapings cannot rust or corrode
  • High impact composite jacket cannot rust or corrode and eliminate potential damage during installation and transit


  • Compliant with OSHA and ANSI tepid water standards
  • Self-operating mixing valve prohibits the delivery of overheated water to prevent scalding
  • Mixing valve designed to ensure a constant flow of tepid water even when an accident causes a loss of electric power
  • Reduces risk of Legionella because water is stored at an elevated temperature
  • Component’s factory assembled simplifies installation
  • 5-year non-pro-rated tank warranty


ESS Emergency Safety Shower Water Heater Part Number Ordering Chart


  1. If other criteria are needed consult our product team.
  2. Example: 389-003000-000 – The ESS Water Heater emergency tepid water delivery system with a storage capacity of 119 Gallons, 85°F set point of the mixing valve, and a 4.5 KW rating. The storage tank is lined with Hydrastone cement and operates at 240 Volts single-phase power.


  • Tank: Hydrastone Cement Lined Steel
  • Storage Capacity: 119 Gallons
  • Cold Water Inlet Size: 1½” Female NPT
  • Tepid Water Outlet Size: 1¼” Female NPT
  • Drain Size: 3/4” GHT
  • Relief Valve Size: 3/4” Female NPT
  • Thermostat Rage: 100°F-180°F
  • Piping: Copper Tubing
  • Mixing Valve Cv: 10.0
  • Pressure Drop at 20 GPM: 4 PSI
  • Minimum Supply Pressure: 30 PSI
  • Hi-Limit: 190°F
  • Design WP: 150 PSI
  • Design TP: 300 PSI
  • Elements: Copper Sheathed
  • Insulation: 3” Polyurethane Foam
  • Jacket: High Impact Colorized Composite
  • Color: Brown and Tan


ESS Sell Sheet
ESS Product Sheet
ESS Operations and Maintenance Manual
Temperature Control for Emergency Safety Equipment Brochure