Why a heating system is balanced and an ordered way to set the lockshield valves for even heat.
Balancing distributes water to match the heat duty of each emitter. On a conventional two-pipe radiator circuit this is commonly done at lockshield valves. Easier paths may need throttling to give more resistant branches their required flow; distance alone does not decide which is which.
- Confirm that the system is clean, properly filled and vented before final balancing.
- Identify the fitted valves and the specified method. Conventional lockshields, preset TRVs and pressure-independent valves are commissioned differently.
- For a manual lockshield procedure, establish the specified initial valve positions, pump setting and heat demand.
- Let the system stabilise before taking flow and return temperatures or measuring flow.
- Adjust each branch to its design duty. Temperature-drop checks must use the design and current load conditions; equal flow or equal measured drops are not universal targets.
- Recheck affected branches and normal control operation after adjustments, then record the settings and measurements.
The aim is adequate heat delivery to every room with the intended water temperatures and controls. For example, emitters serving different room loads may require different flow rates. Follow the system designer’s duties and the valve manufacturer’s commissioning procedure.
One radiator stone cold, the rest fine
When one radiator is cold but the others heat, start at that emitter and its branch. Check for a closed wheelhead or lockshield, a thermostatic valve stuck shut, then trapped air or a blockage. Those local causes fit the pattern better than a boiler or pump fault affecting the whole circuit; check the radiator's valves before rebalancing everything.