Baxi Poor Circulation / System Balancing Issue

Radiators not getting hot or only partially warm while boiler appears to run

Safety Warning

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

Sludge in radiators and pipework, Pump running at low speed or partially blocked, Motorised zone valve stuck closed, Airlocks in system

How to Fix / Troubleshooting

Safety first: Radiators and pipes can become hot; use caution when bleeding.

User checks:

Check that the room thermostat is set above room temperature and calling for heat.
Ensure all radiator valves (and any TRVs) are open.
Bleed radiators starting from the lowest to highest floors, topping up system pressure as needed.
Feel the pipes near the boiler: if the flow is hot but returns are cool, circulation may be restricted.

Professional actions:

An engineer can check pump performance, clean or replace motorised valves, and flush sludge from the system.

Repair Difficulty

Medium 3/5

Required Part

Circulation Pump

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