Gate valves for district heating networks: supply and return lines
District heating is one of the largest users of gate valves. Many networks were built decades ago and are maintained in short summer outages, so reliability and exact dimensional match on replacement matter most.
TAZ Engineering Team · · 6 min
Water parameters
Transmission supply lines typically run at up to 130–150 °C and PN 16–25, with lower parameters on the return. The water can carry dissolved oxygen and suspended solids, especially after repairs.
Materials and design
Supply mains use steel wedge gate valves such as 30s41nzh. Lower-parameter networks and existing chambers often have cast-iron parallel gate valves 30ch6br. Resilient-seated valves are acceptable only where the temperature stays within the rubber’s limit. Modern pre-insulated networks increasingly use fully welded ball valves on branches and gate valves on large mains.
Connections and installation
Chambers usually take flanged valves; direct-buried lines take butt-weld ends. The valve must not carry thermal expansion loads. Provide body supports from DN 300, and consider bypasses and electric actuators on key nodes.
Replacement in existing networks
Measure the face-to-face length, flange drilling and open height; in tight chambers the stem height often decides. A valve with matching dimensions goes in without pipe modification and fits a short outage.
Ordering
State water parameters, DN, PN, end connection, face-to-face, actuation and the outage schedule. TAZ selects the execution and aligns delivery with the repair season.
Checklist
- supply and return temperature and pressure
- water quality
- DN and PN
- steel or cast iron
- flanged or butt-weld
- face-to-face
- open height in chamber
- support and bypass
- actuation
- outage schedule