Error code
Baxi Boiler E20 — Meaning and Safe Advice
The applicable Baxi table describes a short or open circuit at the central-heating temperature sensor. Use the applicable boiler-range table on the Baxi reference. An E-prefixed code is not interchangeable with every similar numeric display.
Quick answer
E20: Central-heating NTC sensor circuit fault
Meaning
Central-heating NTC sensor circuit fault
First safe check
Record the full model number and complete displayed code before attempting a remedy.
Stop if
The warning is active or recurring and the next step would require internal access.
Who to call
Contact a Gas Safe registered engineer qualified for the boiler with the model and full code. The display identifies a reported condition, not a confirmed replacement part.
Internal diagnosis and repair require a qualified professional. Follow only the model-approved user actions described below. Keep checks outside the casing and use only a manufacturer-approved reset where the manual allows it.
What does this error code mean?
The applicable Baxi table describes a short or open circuit at the central-heating temperature sensor.
An NTC circuit warning is not proof that the sensor alone needs replacement.
Use the applicable boiler-range table on the Baxi reference. An E-prefixed code is not interchangeable with every similar numeric display.
Why is this happening?
- The manufacturer-reported condition is: central-heating ntc sensor circuit fault. An engineer must establish the underlying cause on the actual model.
Safe next steps
- Record the full model number and complete displayed code before attempting a remedy.
- Confirm that the manufacturer guidance below applies to that model. Do not use instructions for a different appliance or code suffix.
- Contact a Gas Safe registered engineer qualified for the boiler for diagnosis if the warning is active or recurring.
Can I fix this myself?
NoLimit your actions to the external checks and model guidance described here; internal diagnosis requires a professional.
Safety boundary: Do not remove the boiler casing or work on gas, combustion, flue components or internal wiring.
What not to do
- Do not remove the boiler casing or work on gas, combustion, flue components or internal wiring.
- Do not order replacement parts solely from the code or repeat resets to suppress a returning warning.
Common misdiagnoses
- An NTC circuit warning is not proof that the sensor alone needs replacement.
When to call a heating professional
Contact a Gas Safe registered engineer qualified for the boiler with the model and full code. The display identifies a reported condition, not a confirmed replacement part.
Safety warning
Do not remove the boiler casing or work on gas, combustion, flue components or internal wiring.
Useful hub links
Other Baxi boiler codes
Baxi Boiler E28 — Code Meaning
Flue-temperature NTC circuit fault in the applicable Baxi table
Baxi Boiler E1 — Check the Model
Meaning unconfirmed; exact model evidence required
Baxi Boiler E10 — Meaning and Safe Advice
External-probe fault in the applicable Baxi table
Baxi Boiler E53 — Code Meaning
Flue obstruction in the cited DUO-TEC fault table
Relevant guide
Frequently asked questions
Does E20 prove that a part needs replacement?+
No. Match the model and full code first. The manufacturer definition describes the reported condition; diagnosis establishes whether a repair is needed.
Does this definition apply to every model?+
Use the applicable boiler-range table on the Baxi reference. An E-prefixed code is not interchangeable with every similar numeric display.
Sources and review status
Model dependent · Last reviewed 21 September 2026
- Baxi professional error-code reference
manufacturer support · UK · checked 21 September 2026
The code definition and stated model/region scope. An NTC circuit warning is not proof that the sensor alone needs replacement.