Grant Poor System Balancing or Blocked Branch

Boiler runs but some radiators never get hot, even when valves are open.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Balancing valves incorrectly set, Blocked radiator valve or pipe, Airlock in specific branch, Pump output insufficient for system layout

Safety: Radiators and pipes may be hot; use care when adjusting valves.

User actions:

Engineer actions:

Balance the system by adjusting lockshield valves to ensure even flow.
Check for blockages in radiator valves or pipework and clear or replace as needed.
Bleed air from affected radiators and high points.
Assess whether the pump size and speed are adequate for the system.

Medium 3/5

Lockshield valve

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