How much does it cost to fix Baxi error code 164?

Typical repair cost for the Baxi 164 fault is £120-240 including labour.

164 High

Baxi 164 Fault Code

Q: What does the Baxi 164 fault code mean?

Your boiler has detected a problem with the sensor or switch that monitors water movement, preventing the system from heating up properly.

The Baxi 164 fault code means: your boiler has detected a problem with the sensor or switch that monitors water movement, preventing the system from heating up properly.. It appears on 26 Baxi models in our database.

Technical description: Pressure Sensor Error (UK) – Heating flow switch error (Ireland)

What causes the Baxi 164 fault?

This fault occurs when the boiler detects a mismatch between the internal pump running and the actual movement of water through the system. The most common reason is a faulty pressure sensor or flow switch that is sending incorrect data to the control board, but it can also be caused by a blockage or trapped air preventing water from circulating freely.

This issue is often seen in autumn when the heating is turned on for the first time after summer, as internal parts can sometimes seize or stick during long periods of inactivity.

Typical repair cost £120-240 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Baxi models that show the 164 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi 164 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026