The Baxi A.02.06 code means low system pressure in the heating circuit. The sealed heating system does not have the pressure the boiler expects for normal operation. This is useful information, but the code does not tell you why the pressure is low.
Some pressure loss may be corrected through an approved homeowner control described in the exact model’s user guide. Pressure that keeps falling, will not rise correctly, or is accompanied by water around the boiler or radiators needs professional attention.
What does Baxi A.02.06 mean?
Baxi’s current error-code table defines A.02.06 as “Low system pressure in heating circuit.” The heating circuit is the closed loop of water that carries heat from the boiler to radiators or other emitters and back again.
The pressure reading helps the boiler confirm that this circuit contains enough water to operate as intended. When the reading drops below the level expected by the controls, the boiler can display A.02.06. Depending on the model and conditions, heating or hot water may be restricted until the pressure issue is dealt with.
Which Baxi boilers can show A.02.06?
Baxi currently lists A.02.06 for this Combi 2 and System 2 group:
- Baxi 200 Combi 2
- Baxi 400 Combi 2
- Baxi 600 Combi 2
- Baxi 800 Combi 2
- Baxi Assure 500 Combi 2
- Baxi 600 System 2
- Baxi 800 System 2
- Baxi Assure 500 System 2
Always confirm the complete model name from the outside of the appliance or its paperwork. Different Baxi ranges can use different code formats, pressure displays and approved user controls.
What pressure should a Baxi boiler have?
There is no single number that should be copied across every Baxi model and every operating condition. Use the pressure guidance, marked normal zone and approved procedure in the user guide for your exact appliance. The pressure can also look different when the heating is cold and when the system is warm.
If the pressure display or gauge is below the normal range stated for your model, A.02.06 is consistent with that low reading. Do not keep adding water in an attempt to reach a guessed target. Too much pressure creates a different problem.
Why might heating-system pressure fall?
The public code description confirms low pressure but does not identify the cause. Useful possibilities for an engineer to consider can include water having been released from the system, a visible or hidden leak, or a problem elsewhere in the sealed heating arrangement. The display cannot distinguish between them.
A one-off low reading and pressure that repeatedly falls are not the same situation. If you restore pressure using the model’s approved homeowner procedure and the reading soon drops again, make a note of how quickly it happened and book a repair. Repeated topping up is not a solution to continuing water loss.
What might you notice at home?
Alongside A.02.06, you may notice that the boiler has stopped responding to heating demand, radiators remain cold, or hot-water service is affected. You might also see a low reading on the boiler’s pressure display or external gauge.
Do not assume every cold radiator proves the same pressure problem. Controls, radiator valves and other system conditions can create similar symptoms. The combination of the exact code, model and pressure indication is the useful evidence.
What can you safely check?
Without opening the boiler or changing internal parts, you can:
- Write down A.02.06 exactly, including punctuation and leading zeros.
- Confirm the full Baxi model from the visible label or paperwork.
- Read the current pressure from the normal homeowner display or gauge.
- Compare it with the normal range shown in the exact model’s user guide.
- Look around accessible radiators, visible pipe joints and beneath the boiler for obvious water.
- Note whether the code appeared after a radiator was bled or other heating work was completed.
- Record whether pressure has dropped before and how quickly it changed.
- Check whether another code appears alongside or after A.02.06.
Never remove the boiler casing or reach into the appliance to look for a leak. Do not operate an unidentified valve, improvise a filling connection or dismantle radiator, pressure-sensor, expansion-vessel or relief-valve components.
Can you repressurise the boiler yourself?
Only use a homeowner repressurising method if it is clearly described for your exact boiler in the official user guide and you can identify every approved external control without doubt. Follow that guide exactly and stop at the specified normal range.
If the control arrangement does not match the manual, you cannot find the right guide, the filling control is inaccessible, water leaks, or pressure does not respond as described, stop and book a professional repair. Do not copy a video for a different boiler: filling arrangements vary, even between related models.
Should you reset after correcting low pressure?
Follow the sequence in the exact model’s user guide. Some appliances may resume after the pressure returns to the approved range; others may require the user action specified by Baxi. Do not keep resetting if A.02.06 remains or returns. Repeated resets will not correct ongoing pressure loss.
How is A.02.06 different from other Baxi pressure codes?
For the same current model group, Baxi lists H.02.07 as low pressure in the heating circuit “permanently”. It also lists E.02.39 as the minimum pressure not being reached after six minutes of automatic filling. These are separate displayed messages with different wording.
Record the exact code rather than describing it simply as “the low-pressure code”. That prevents advice for one condition being applied to another, particularly where an automatic-filling arrangement may be involved.
When does low pressure need a repair?
Arrange professional help when:
- A.02.06 remains after following the exact approved user instructions;
- pressure rises but soon falls again;
- you have to add water repeatedly;
- there is water beneath the boiler or around the heating system;
- the gauge behaves unexpectedly or does not respond;
- heating or hot water remains unavailable;
- another fault code appears.
A recurring pressure problem deserves attention even if the boiler temporarily starts again. Tell the engineer how often it happens, whether any water is visible, and what work was recently carried out. That history is more helpful than guessing at a particular part.
What if water is leaking?
Keep clear of hot water and electrical equipment. If water is near electrical fittings, the leak is significant, or the ceiling below is affected, treat it as urgent and seek professional help. Do not remove covers or tighten internal fittings.
Gas-appliance and casing-off work must be completed by an appropriately qualified Gas Safe registered engineer. If you smell gas or a carbon-monoxide alarm sounds, leave the appliance alone, open doors and windows, leave the property and call the National Gas Emergency Service on 0800 111 999 from a safe place.
Does Baxi A.02.06 keep returning?
Book a fixed-price boiler repair aimed at fixing the fault and restoring reliable pressure, without repeated topping up or opening the appliance.
Quick answers about Baxi A.02.06
What does A.02.06 mean on a Baxi boiler?
It means low system pressure in the heating circuit.
Can low pressure stop heating or hot water?
Yes. The boiler may restrict operation when the heating circuit does not have the pressure it expects.
What pressure should I add?
Use only the normal range and approved method in the user guide for your exact model. Do not rely on a number taken from another boiler.
Why does the pressure keep dropping?
The code does not identify the cause. If pressure falls again after the approved user action, book a repair rather than repeatedly adding water.
Is A.02.06 the same as H.02.07?
No. Baxi lists H.02.07 separately as low pressure in the heating circuit permanently. Record the exact code shown.
Can I open the boiler to find a leak?
No. Keep the casing closed. Check only accessible areas and use a suitably qualified professional for internal work.