Valves and flow equipment for hot water and steam networks

Hot water and steam networks are used in HVAC installations, industrial buildings, hospitals, hotels, production plants and technical facilities where heat must be transferred with controlled flow, pressure and temperature. Valve and flow equipment selection is based on the thermal load, medium type, operating pressure, supply and return temperature and control system requirements.

Hot water circuits operate by circulating water through boilers, heat exchangers, headers, fan coils, air handling units, radiators or underfloor heating systems. Steam networks also require condensate management, removal of air and non-condensable gases, and protection against overpressure and water hammer.

Typical applications

• Hot water circuits for space heating, domestic hot water and air handling units.
• Steam networks for heat exchangers, air heaters, radiators and process users.
• Heating substations with heat exchangers and secondary water circuits.
• Condensate and drainage lines on headers, heat exchangers and steam pipework.
• Steam pressure reducing stations and hot water pressure regulation points.
• Filling, bypass, venting, draining and recirculation lines.
• Auxiliary compressed air networks for pneumatic actuators and control instruments.

Equipment selection criteria

• Supply and return temperature or saturated steam temperature.
• Operating pressure, design pressure and valve differential pressure.
• Required flow rate, thermal load and allowable pressure drop.
• Material compatibility with hot water, steam, condensate or treated network water.
• Isolation, control, non-return, balancing or protection function.
• Start-up, shutdown, part-load and thermal expansion conditions.
• Automation, fail position and position indication requirements.
• Access for inspection, maintenance and isolation of network sections.

Indicative equipment

• Isolation valves for hot water, steam and condensate networks.
• Control valves for flow, pressure and temperature regulation.
• Balancing valves for hydraulic adjustment of hot water circuits.
• Pressure reducing valves and pressure regulators for steam and water networks.
• Check valves for pump protection and backflow prevention.
• Safety and relief valves for boilers, vessels, heat exchangers and pipework.
• Steam traps for continuous or intermittent condensate removal.
• Air vents, air separators and network drainage equipment.
• Line strainers for protection of control valves, pumps, heat exchangers and instruments.
• Electric and pneumatic actuators for connection to BMS, PLC or automation systems.

For each installation, the thermal load, temperature difference, operating pressure, differential pressure, installation point, isolation or control requirement and control logic should be reviewed. These data define the valve type, nominal size, pressure class, construction materials, tightness requirements and suitable actuation method.