Baxi E20 fault code: what it means and what to do

Baxi fault code E20 means the boiler has detected a problem with the central-heating NTC temperature sensor. Baxi describes it as a short-circuit or open-circuit fault.

The code is listed for several Baxi ranges, including the Platinum Compact, Duo-tec Compact, 600, 800, Assure, Platinum, Megaflo and EcoBlue families. Always check the user guide for your exact model because controls and reset methods differ.

What is the central-heating NTC sensor?

The NTC sensor measures heating-water temperature so the boiler can control the burner safely and efficiently. “NTC” describes the type of temperature-sensitive component used.

An open-circuit or short-circuit reading means the boiler is not receiving a believable temperature signal. It may stop heating rather than run without reliable temperature information.

What can cause Baxi code E20?

The fault can involve the temperature sensor itself, its electrical connection, associated wiring or the boiler control electronics. The display code cannot tell you which of these is responsible.

Those parts are inside the appliance. Do not remove the boiler casing, unplug sensor leads, test resistance or attempt to bridge a connection. Internal boiler and gas-appliance work should be carried out by a suitably qualified Gas Safe registered engineer.

What can you check safely?

You can check that the boiler has power, that normal heating controls are calling for heat and that no unrelated power cut or tripped external switch is affecting the appliance. Note whether the code appeared suddenly, after a power interruption or after previous intermittent heating problems; that information can help the engineer.

Keep the front casing closed. E20 is not caused by a room thermostat setting, so repeatedly turning the thermostat up will not correct it.

Can I reset a Baxi boiler showing E20?

Baxi publishes different reset methods for different controls. Follow only the user instructions for your exact boiler. You may try one reset if your model guide permits it.

If E20 remains, returns or the boiler repeatedly locks out, stop resetting it and book a repair. Baxi advises that frequent lockout indicates a fault requiring an installer or service engineer.

Will E20 affect heating and hot water?

Because the boiler cannot rely on its central-heating temperature reading, it may stop central heating and, depending on the appliance design and fault state, hot water may also be unavailable. Do not assume that temporary operation means the fault has repaired itself if E20 has been recurring.

What will an engineer do?

The engineer will confirm the full model, read the fault history and follow Baxi’s instructions for testing the sensor circuit, connections and controls. The correct repair depends on those results rather than replacing a sensor solely because E20 is displayed.

Quick answer

Baxi E20 means a central-heating NTC sensor open-circuit or short-circuit fault. Keep the casing closed, use one model-approved reset at most, and arrange a repair if the code remains or returns.