ESS Tepid Water Heater Overview
The electric ESS heater stores water at an elevated temperature to help reduce the risk of Legionella growth while maintaining a ready hot-water supply for emergency use. Factory-assembled components simplify installation and reduce field assembly, while the storage tank is backed by a 5-year non-pro-rated warranty.
For facilities with an available steam supply, the self-operating Therm-O-Mix® Station provides an alternative method of producing tepid water without electrical power.
Design Features
- Triple-redundant Therm-O-Mix®/WWM thermostatic mixing valve is factory-mounted and piped to the heater for integrated temperature control
- All electrical operating controls are factory selected and wired to ensure reliable operation
- ½” Hydrastone cement lining supports tank life at elevated storage temperatures without anodic protection
- 3″ Polyurethane Foam Insulation reduces standby heat loss by over 24% compared with 2″ insulated tanks
- Copper-silicon alloy tappings cannot rust or corrode
- High impact composite jacket cannot rust or corrode and helps prevent damage during installation and transit
Typical Applications
The ESS provides a dedicated tepid-water source for emergency safety showers, eyewash stations, and face/eyewash equipment where an adequate facility hot-water supply is not available. Typical installations include chemical processing, petrochemical, pharmaceutical, manufacturing, and other facilities where emergency drench equipment is required.
Typical ESS System Configurations
Example installation showing the ESS supplying tepid water to a safety shower and face/eyewash fixture. System components vary by application.
ESS Resources
Product Literature
Specification & Installation
Specifications
- Tank: Hydrastone Cement Lined Steel
- Storage Capacity: 119 Gallons
- Voltages: 120 thru 600 Volt
- Phase: 1 or 3 Φ
- 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 Range: 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
- Tank Warranty Standard: 5 Year Non Pro-Rated Optional: 10 Year Non Pro-Rated
- Electrical Warranty: 1 Year
ESS Selection and Configuration Considerations
Sizing and configuration depend on the emergency fixtures being served and the available facility conditions.
- Fixture demand – Identify whether the system will serve an eyewash, face/eyewash, emergency shower, or simultaneous fixtures.
- Required flow and duration – Confirm the required total flow rate and flushing duration for the connected equipment.
- Incoming water conditions – Confirm cold-water temperature and available supply pressure, which affect mixed-water capacity and system pressure drop.
- Electrical service – Confirm available voltage, phase, and required heater kW.
- Outlet temperature – Standard configurations use an 85°F mixing-valve set point, with a 75°F option available.
- Installation environment – Outdoor, hazardous-location, freeze-protection, alarm, and seismic requirements may require optional equipment.
ESS Part Number Designation
Example: 389-003000-000 – The ESS is a tepid water delivery system with a 119-gallon storage capacity, 85°F mixing valve set point and a 4.5 kW rating. The storage tank is lined with Hydrastone cement and operates at 240 Volts single-phase power.
**Not all model configurations are available. Please reference kW and Amperage Selection Chart to ensure model is available. Contact ThermOmegaTech® or your local Distributor for assistance**
Optional Equipment
Controller:
- C31 Leak Detection – Includes Sensor Pad and Dry Contact for BMS Notification
- C35 BACnet Communication Module with T1000 Digital Controller
- C55 Low Temp Alarm Dry Contact
- C56 High Temp Alarm Dry Contact C57 Flow Alarm Dry Contact
General:
- G9 Explosion Resistant Construction (Specify Class, Division, Group, and Temperature Class)
- G21 NEMA 4X Valve Enclosure
- G25 Outdoor Weather Package (304 SS Jacket and 6″ Legs. NEMA 4X Electrical Housing and Mixing Valve Housing
- G35 All Hot & Cold Water Piping on the Heater Package to be Heat Traced from the Factory for Freeze Protection
Vessel:
- V1 NSF5 Approved Legs
- V20 Integrally Welded Seismic Attachment Points
How the ESS Tepid Water Heater Operates
When an emergency fixture is activated, the Therm-O-Mix®/WWM blends 170°F stored water with incoming cold water to maintain a constant 85°F tepid outlet temperature regardless of inlet pressure and temperature variations. The factory-set mixing valve is tamper-resistant.
The ESS supports flow rates from 0.4 GPM for an eyewash up to 23 GPM for simultaneous operation of a safety shower and eye/face wash fixture. This allows the system to meet both low-flow eyewash demand and higher-volume emergency drench requirements.
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.
Triple Redundant 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.
