Baxi H.02-.02 Fault Code: Causes, Fixes & Repair Costs
What does the Baxi H.02-.02 fault code mean?
The H.02-.02 code is a temporary blocking fault indicating that the boiler's printed circuit board (PCB) has not received — or has lost — its essential configuration parameters, known internally as C1 and C2. These parameters are the stored instructions that tell the PCB exactly what type of appliance it is controlling and how it should behave. Without them, the boiler cannot operate safely, so it halts and displays this code. The fault typically surfaces on a brand-new installation that hasn't been fully commissioned, or after a PCB replacement where the new board hasn't yet been programmed. It can also appear if stored memory is lost following a power surge or prolonged power cut. Because it is a temporary (H-prefix) blocking code rather than a permanent lockout, the boiler may recover once the underlying configuration issue is resolved — but that resolution almost always requires an engineer's involvement. Note that this code sits within a small family of related parameter faults: H.02-.03 indicates that C1/C2 settings have been entered but are incorrect for the appliance, while H.02-.04 signals a broader parameter fault where values are present but invalid. If your display shows either of those variants, the diagnosis and remedy are very similar to H.02-.02.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. 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
- New boiler or new PCB not commissioned Common
By far the most frequent trigger. When a boiler is first installed, or when a replacement PCB is fitted, the engineer must enter the correct C1/C2 configuration values via the boiler's service menu to match the unit's specific model and output. If that step is skipped or interrupted, the boiler displays H.02-.02 immediately on first startup.
- PCB memory loss after power surge or outage Sometimes
A sudden loss of mains power or a voltage spike can wipe the stored configuration data from the PCB's non-volatile memory. The hardware itself may be undamaged, but the parameters need to be re-entered before normal operation can resume.
- Ageing or failing PCB Rare
As a PCB gets older, onboard memory chips and capacitors can degrade, making it unable to reliably hold configuration data. The code may reappear even after reconfiguration if the board is no longer functioning correctly, pointing to the need for repair or replacement.
How to fix it
- Attempt a single boiler reset DIY safe
Locate the reset button on the front panel — on most Baxi models it is clearly labelled. Press and hold it for around three to five seconds until the boiler attempts to restart. Only try this once. If the H.02-.02 code returns straight away, further resets will not resolve the issue and you should move on to the next step.
- Check for any obvious power supply issues DIY safe
Make sure the boiler's mains switch is on and that no fuses or circuit breakers related to the boiler have tripped. If there has been a recent power outage or electrical storm in your home, note this down — it is useful information for the engineer and may point to a memory-wipe rather than hardware failure.
- Call a Gas Safe registered engineer to reconfigure the PCB Gas Safe engineer
A qualified engineer will access the boiler's service or installer menu and re-enter the correct C1/C2 parameters for your specific model. On a new installation this is a standard commissioning task and should take no more than 30–60 minutes. If the boiler was recently commissioned by an installer, contact them first as this may be covered under their installation warranty or guarantee.
- Engineer to inspect and test the PCB if reconfiguration fails Gas Safe engineer
If the parameters cannot be saved, or if the fault returns shortly after reconfiguration, the PCB itself is likely damaged. The engineer will test the board and advise whether a repair is viable or whether a full PCB replacement is required. A replacement PCB must be correctly sourced for your exact Baxi model and then configured before the boiler is returned to service.
- Consider boiler age and overall repair cost DIY safe
If your boiler is under 10 years old, a PCB repair or replacement is almost always worthwhile. For boilers aged 12 years or more, particularly those with a history of recurring faults, it is worth asking your engineer to give an honest assessment of overall condition. If the repair cost approaches or exceeds half the price of a new boiler installation, replacement may be the more sensible long-term decision.
Parts you may need
- Baxi PCB (model-specific replacement board) · from £220
- PCB configuration / programming service (labour) · from £100
- Mains surge protection device (preventative) · from £35
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 £80–£350, depending on the underlying cause.
Frequently asked questions
Can I fix the H.02-.02 fault myself by resetting the boiler?
You can try a single reset — it costs nothing and occasionally clears a transient glitch. However, because this fault is specifically about missing or lost PCB configuration data, a reset alone will not fix it if the parameters have never been entered or have been wiped. You will need a Gas Safe registered engineer to access the service menu and programme the correct settings. Do not reset the boiler more than once or twice, as repeated resets without addressing the root cause can mask a developing fault.
How much does it cost to fix a Baxi H.02-.02 fault in the UK?
If the fix is simply reconfiguring the PCB — which is the most common scenario on a newly installed or recently serviced boiler — expect to pay roughly £80 to £150 covering the engineer's call-out and labour. If the PCB has failed and needs replacing, the total cost including parts and labour typically rises to £300–£500 for a Baxi model, since Baxi parts are widely stocked and generally well-priced. In exceptional cases where a high-specification or older board is involved, costs can exceed this range — always get two or three quotes from independent Gas Safe engineers, who tend to charge less than large national service providers.
Why does H.02-.02 appear on a brand-new Baxi boiler?
This is actually quite normal and not a sign that something is seriously wrong with the boiler. On a new installation, the PCB is supplied in an unconfigured state and must be programmed by the installing engineer using the model's specific C1/C2 parameters during commissioning. If the code appears immediately after installation it almost certainly means this step was missed or not completed properly. Contact your installer — reconfiguring the board should be covered as part of the installation work at no extra charge.
What is the difference between fault codes H.02-.02, H.02-.03, and H.02-.04?
All three relate to PCB configuration problems but at slightly different stages. H.02-.02 means no parameters have been entered at all — the board is completely unconfigured. H.02-.03 means parameters have been entered but the values are incorrect for the boiler model, which can happen if the wrong product code is used during programming. H.02-.04 is a broader parameter fault where values are present but invalid or corrupted. In practice the remedy for all three involves a Gas Safe engineer accessing the service menu to verify and correctly enter the configuration data, or replacing the PCB if the board cannot hold the settings.