Baxi E.02-.21 Fault Code: Causes, Fixes & Repair Costs
What does the Baxi E.02-.21 fault code mean?
The E.02-.21 is a permanent lockout fault on Baxi boilers. The 'E.' prefix tells you straight away that this won't clear on its own — it signals a hardware configuration problem rather than a transient operational hiccup. Specifically, the boiler's PCB (Printed Circuit Board) has detected that Jumper 3 has been moved or is in an unexpected position. Jumpers are tiny physical connectors on a PCB that tell the board how the boiler is configured — for example, whether it's running as a combi, system, or regular (heat-only) unit. When the boiler's software sees that Jumper 3 no longer matches the expected setting, it raises this permanent fault and refuses to fire until the situation is corrected. The boiler will remain locked out until a Gas Safe engineer inspects the board, verifies the correct jumper position against Baxi's technical documentation, and resets the unit. Note: Baxi fault codes are displayed in two parts on the panel — always wait for the complete code to scroll through before diagnosing, as codes sharing an early sequence can indicate entirely different problems.
General guidance only — not a substitute for professional advice. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Jumper accidentally moved during a recent service or repair Common
The most common trigger. If your boiler has recently been serviced, had a component replaced, or had any engineer work inside the casing, Jumper 3 may have been nudged out of position inadvertently. Mention any recent work to your engineer — it's a strong clue.
- Incorrect jumper configuration after PCB replacement Common
When a PCB is replaced, the jumpers on the old board should be replicated exactly on the new one. If this step was overlooked or done incorrectly, the boiler will detect the mismatch and raise this fault the first time it runs.
- Wrong initial installation configuration Sometimes
If Jumper 3 was set incorrectly when the boiler was first installed — perhaps because the installer referenced the wrong model documentation or set it for a different system type — the fault may only surface after a firmware check or reset.
- Jumper worked loose due to vibration or age Sometimes
On older boilers, the physical connectors on the PCB can gradually loosen over years of normal operation and vibration. A jumper that was once secure may eventually lose contact or shift slightly, causing the boiler to register the change.
- PCB damage or corrosion Rare
Water ingress, condensation, or electrical damage to the PCB can affect the jumper connector or the surrounding circuitry, causing the board to misread the jumper state even if it hasn't physically moved.
How to fix it
- Check when the boiler was last serviced or had work done DIY safe
Think back — has an engineer been inside the boiler recently? A recent service, repair, or PCB replacement is the most likely trigger for this fault. Note this down before calling, as it will help your engineer diagnose faster and may affect warranty eligibility.
- Confirm the full fault code on the display DIY safe
Baxi boilers display fault codes in two parts. Wait for the complete sequence to scroll through and confirm you are seeing E.02-.21 in full. Codes that begin similarly can mean very different things, so accuracy here matters.
- Attempt a boiler reset (once or twice only) DIY safe
Locate the reset button on your boiler — usually a flame icon or a dedicated button on the control panel. Hold it for the required duration per your model's instructions. This will not fix the underlying jumper issue, but it confirms the fault is permanent and will not clear without intervention. Do not reset more than two or three times.
- Do not attempt to open the boiler casing or touch the PCB Gas Safe engineer
Moving jumpers on a PCB requires knowledge of the exact boiler model configuration, access to Baxi's technical wiring diagrams (available to professionals via the Baxi Works portal), and appropriate electrical safety precautions. Incorrect jumper positioning can cause further faults, damage the board, or invalidate your warranty. This is strictly engineer territory.
- Call a Gas Safe registered engineer to inspect and reposition Jumper 3 Gas Safe engineer
The engineer will open the casing, locate Jumper 3 on the PCB, and cross-reference the correct position against Baxi's model-specific documentation. If the jumper has simply been dislodged, repositioning it and resetting the boiler is typically a quick fix. If the PCB itself is damaged or the jumper connector is broken, a full board replacement may be needed. Always ask for a Gas Safe ID number before any work begins.
Parts you may need
- Baxi PCB (Printed Circuit Board) · from £180
- PCB jumper connector/header · from £8
- Boiler casing seal/gasket (if disturbed during repair) · from £15
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £100–£350, depending on the underlying cause.
Frequently asked questions
Can I fix the Baxi E.02-.21 fault myself?
No — this is not a homeowner repair. Moving or adjusting jumpers on a boiler PCB requires the correct Baxi technical documentation (accessible only to professionals via Baxi Works), electrical knowledge, and Gas Safe registration. Attempting it yourself risks further damage to the board, additional faults, and could void your warranty. The good news is that if the fix is simply repositioning a dislodged jumper, an engineer visit should be relatively quick and inexpensive.
How much does it cost to fix the E.02-.21 fault?
If the engineer only needs to reposition Jumper 3, you're likely looking at a standard call-out charge plus a small amount of labour — typically £100 to £200 in total. If the PCB itself is faulty or needs replacing, costs rise significantly: a full PCB replacement including parts and labour can run to £450–£700, with London and South East rates tending toward the top of that range. Always ask for a quote before authorising any parts.
Will my Baxi warranty cover the E.02-.21 fault?
It depends. Baxi boilers come with a standard 2-year warranty, extendable to up to 10 years if installed by a Baxi-accredited installer and serviced annually by a Gas Safe engineer. If your boiler is within warranty and has been properly maintained, this fault — particularly if triggered by a manufacturing or installation defect — may well be covered. Contact Baxi directly or check your warranty documentation before commissioning a private repair.
Why has this fault appeared after my boiler was recently serviced?
This is actually the most common scenario for E.02-.21. During a service or repair, an engineer working inside the casing may have accidentally disturbed Jumper 3 without realising. If the fault appeared shortly after a visit, contact the engineer or their company first — they should return to rectify it, ideally at no extra charge if the disturbance was accidental on their part.