ST SERIES
Semi-Instantaneous Water Heaters
The ST Series Semi-Instantaneous Water Heaters from Diversified Heat Transfer are designed to provide reliable domestic hot water in commercial and institutional facilities where demand can change quickly. By combining storage capacity with rapid heat transfer, semi-instantaneous systems deliver consistent hot water while reducing recovery time during peak usage.
These systems are commonly used in facilities such as hospitals, schools, universities, hotels, and government buildings where dependable hot water supply is essential for daily operations.
The ST Series integrates easily with boiler systems and central plants, using steam or hot water as the heating medium to efficiently produce domestic hot water. Built with durable components and engineered for long-term performance, DHT semi-instantaneous water heaters provide a dependable solution for demanding water heating applications.
Key Features
- Steam-to-Water and Water-to-Water configurations
- Available in single and double wall construction
- Copper (standard) and optional CuNi or SS bundle material of construction
- Copper, Cu-Ni or SS material in contact with water (potable water)
- Fully packaged solution for quick and easy single point connections
- Available in vertical or horizontal (optional) construction
- Compact footprint that fits through a standard doorway
- Standard trim is available up to 200 psi with optional trim up to 250 psi
- Fully modulating energy input for precise temperature control
- Available in electronic or pneumatic controls
- Advanced PID touchscreen controls with ModBus IP and BACnet IP BMS integration
- Domestic water pressure drop less than 5 PSI
- Low lead compliant
- Made in America
- ASME B&PV Code Section VIII, Division 1 stamped
- Warranty: Tube Bundle (5 years), Shell (10 years)
Technical Documents
Literature and Performance Data
Product and Component Drawings
Installation and Piping Drawings
ST VERTICAL INSTALLATION CLEARANCE DRAWING (dwg)
ST VERTICAL PIPING & INSTALL (pdf)
ST VERTICAL PIPING & INSTALL (dwg)
ST VERTICAL PIPING & INSTALL SINGLE UNIT STORAGE TANK (pdf)
ST VERTICAL PIPING & INSTALL SINGLE UNIT STORAGE TANK (dwg)
ST VERTICAL PIPING & INSTALL MULTIPLE UNIT (pdf)
STV PIPING & INSTALL MULTIPLE UNIT (dwg)
ST VERTICAL PIPING & INSTALL MULTIPLE UNIT WITH TANK (pdf)
ST VERTICAL PIPING & INSTALL MULTIPLE UNIT WITH TANK (dwg)
ST HORIZONTAL INSTALLATION CLEARANCE DRAWING (pdf)
Wiring Diagrams
ST SERIES ELECTRICAL WIRING SCHEMATIC DRAWING FOR SKB/SKC/SKD (pdf)
ST SERIES ELECTRICAL WIRING SCHEMATIC DRAWING FOR SK CONTROL VALVE with PSA actuator (pdf)
ST SERIES ELECTRICAL WIRING SCHEMATIC DRAWING FOR HIGH PRESSURE CONTROL VALVE (pdf)
ST SERIES ELECTRICAL WIRING DIAGRAM FOR SK CONTROL VALVE WITH PSA ACTUATOR 2024 & LATER (pdf)
ST SERIES ELECTRICAL WIRING DIAGRAM FOR SK CONTROL VALVE WITH PSA ACTUATOR 2024 & LATER (dwg)
Specifications
STV Series- Vertical construction – Steam to Water-Single Wall-Electronic Controls (doc)
STV Series – Vertical construction – Steam to Water-Double Wall-Electronic Controls (doc)
STH Series- Horizontal construction – Steam to Water-Single Wall-Electronic Controls (doc)
STH Series – Horizontal Construction – Steam to Water-Double Wall-Electronic Controls (doc)
Installation, Operation and Maintenance Manuals (IOM) & Forms
Warranty
Markets We Serve
Education
Healthcare
Hospitality
Government & Military
Multifamily Housing
Manufacturing & Industrial
Locate a Manufacturer Rep
DHT products are available through an extensive network of trusted manufacturer reps. Whether you need local support or technical expertise, our partners are ready to help you find the right solution.
Frequently Asked Questions
Find answers to commonly asked questions about our products and services.
A semi-instantaneous water heater produces domestic hot water on demand using a heat exchanger rather than storing large volumes of heated water. This design provides fast recovery, consistent temperature control, and improved energy efficiency compared to traditional storage systems.
The ST Series is available in both steam-to-water and water-to-water configurations. This allows the system to integrate easily with existing central plants, district energy systems, or boiler systems already serving the facility.
Answer
The ST Series can be supplied with electronic or pneumatic controls. Advanced electronic PID touchscreen controls are also available and can integrate with building management systems through ModBus IP or BacNet IP for improved monitoring and temperature control.
ST Series units are widely used in healthcare facilities, multifamily buildings, hotels, schools, food processing plants, and industrial facilities where reliable domestic hot water and rapid recovery are required.
Answer