Baxi Short Cycling / Poor Heat Transfer

Furnace frequently short-cycles, turning on and off every few minutes without reaching set temperature

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

Oversized furnace relative to system, Blocked or partially blocked primary heat exchanger, Faulty temperature sensor causing premature shutdown, Low system water volume

How to Fix / Troubleshooting

Safety: Turn off power before removing covers.

Check system pressure and volume: Ensure the system is properly filled and all radiators/loops are open to increase water volume.
Bleed air: Remove air from radiators and high points to improve heat transfer.
Clean filters: Clean any system filters or strainers to improve flow through the Baxi heat exchanger.
Professional assessment: A heating engineer can check for scaling in the primary heat exchanger and adjust control parameters if available.

Repair Difficulty

Medium 3/5

Required Part

Primary Heat Exchanger

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