Immergas boiler error 01: what to do if it will not ignite

Error 01 on an Immergas boiler indicates an ignition failure lockout: the appliance receives a demand for heating or hot water but does not complete ignition within the allowed time. On models such as the Victrix 26 2 I and Victrix EXA 32 ErP, the user can attempt a reset using the Reset control, following the model manual. If the lockout returns, do not keep trying: the boiler needs a professional diagnosis, not speculative replacement parts.

If you have a problem with your boiler, you can use our free error code finder. It can help you identify errors and find clear, practical troubleshooting information.

The lockout identifies failed ignition, not a broken part

The boiler must complete an operating sequence before it can keep the burner alight. When that sequence does not finish correctly, the system stops the attempt and displays the warning. The number identifies the outcome detected by the control system, but not the exact underlying cause. Two appliances showing the same 01 code may therefore need different repairs, or neither may need a replacement component.

The reference manuals for the Victrix 26 2 I and Victrix EXA 32 ErP acknowledge that this lockout may occur during initial startup or after an extended period without use. In those circumstances, the user reset described in the manual can be attempted. However, automatically blaming summer inactivity would be premature: that explanation is no longer sufficient when the fault keeps returning on subsequent starts.

The term code 1 is often used to mean 01, with the initial zero omitted. Even so, it is important to record the complete display indication and the exact appliance name. Do not use another brand’s code chart or assume that every Immergas range shares every warning. Identifying the model, using the documentation or an accessible external label, is the starting point for interpreting the display correctly.

A reset is a test, not a substitute for repair

If there is no smell of gas, no sign of abnormal combustion and no other unsafe condition, you can perform the reset described in the model manual. On the reference Victrix models, this uses the Reset control on the panel. It does not require removing the casing or accessing internal parts. Control layouts can differ between versions, so do not copy a button combination intended for another appliance.

There is no universal button-hold duration that applies to every Immergas boiler. Nor is there any need to repeatedly switch the main power off and on, unplug the appliance or access engineer menus. The reasonable approach is to use the user control as instructed and check whether the boiler responds to demand again. Resetting does not repair a fault that is still present; it simply allows another operating attempt.

If 01 appears again, stop trying and arrange an inspection by an appropriately qualified engineer. Repeated resets do not provide a diagnosis and may obscure the pattern that helps locate the problem. An isolated lockout after months of inactivity is not the same as one occurring every morning or whenever a tap opens: frequency changes the assessment, even when the displayed number remains identical.

If the reset succeeds and the appliance continues working normally, its performance can be monitored without assuming any part is defective. However, getting hot water for a few minutes does not, by itself, prove that the problem is resolved. If it locks out again, do not keep it running through repeated resets. A temporary recovery is also useful information for the engineer, particularly if you note the circumstances in which it happens.

Check supply information without working on the gas system

A supply interruption can prevent ignition even when the boiler has electrical power and its display is working. Before blaming an internal component, check whether the gas network operator has reported an incident and whether the property has an active supply. For cylinder or tank installations, possible fuel depletion should be checked through the normal supply indicators, without dismantling connections or regulators.

Gas being available at the property does not guarantee that it reaches the burner under the required conditions. Pressure, regulation and gas valve operation require professional checks. Users must not purge pipework, loosen a fitting to see whether gas escapes or adjust components. Those actions involve the fuel supply circuit and are outside the scope of household checks, even when they appear quick or straightforward.

If you smell gas, do not press Reset, operate electrical switches or light a flame to test the supply. Avoid ignition sources, leave the area and contact the appropriate gas emergency service from a safe location. In that situation, resetting the boiler is not the priority. The display warning becomes secondary to the possibility of a gas leak.

Internal faults need testing, not speculative replacement parts

Possible causes for an engineer to assess include ignition and flame detection components, gas delivery to the burner and combustion conditions. A damaged electrode or gas valve problem may contribute to a failed start, but 01 does not confirm either diagnosis. Verification must come before replacement, using the checks appropriate to the exact boiler version.

Electrodes are not a user-accessible cleaning area. Reaching them may require opening combustion-related assemblies, and their position affects operation. Adjusting the burner, injectors or air-to-gas mixture is also not a user task. Even if an online description presents the job as simply cleaning or realigning something, it requires a qualified professional and subsequent checks that cannot be replaced by a visual inspection.

The air intake and flue system may also form part of the diagnosis where the circumstances warrant it. From a safe position, you can look for an obvious obstruction at an accessible external terminal, but do not dismantle ducts or insert objects into them. If the check requires climbing onto a roof, removing a system grille or reaching a high location, the user check ends there and professional work begins.

Erratic starting does not, on its own, prove that the electronic control board has failed. The electronics receive signals from other components, and an incorrect signal can create symptoms resembling a control fault. Buying a board because the behaviour seems unpredictable may add expense without solving anything. What matters is checking the ignition sequence, not choosing the most expensive part or the one a shop associates with the code.

Other Victrix Omnia warnings help distinguish different faults

Code 01 should not be confused with every problem that leaves a home without heating. The Victrix Omnia, for example, has specific warnings for low system pressure, circulation and combustion-related anomalies. This table provides a selection of codes for that range to distinguish related situations. It does not replace the complete manual and must not be automatically applied to an Eolo or another Victrix model.

The distinction between 01 and 10 is particularly important: ignition and pressure have separate warnings. Seeing 01 is not a reason to open the filling valve. You can read the pressure gauge and report its reading, but adding water unnecessarily introduces another variable and does not, by itself, solve an ignition problem. Any work on the circuit must follow the appliance-specific instructions and remain within safe limits.

Be cautious with charts that combine different models without distinguishing them. Some assign several meanings to the same number because they mix generations or configurations. That discrepancy cannot be resolved by choosing whichever description sounds closest to the symptoms: the documentation for the exact version takes precedence. A fan, sensor or flue warning from another range does not allow you to reinterpret 01 on the boiler in front of you.

If it happens only when a tap opens, the context matters

A combination boiler may receive demand from the heating system or the domestic hot water supply. If the lockout occurs with only one function, report that accurately. Working radiators alongside failed hot water, or the reverse, helps define the circumstances of the problem. However, it does not automatically identify a component or turn the fault into a suitable do-it-yourself repair.

When behaviour differs between taps, it is also useful to distinguish inadequate flow from an actual boiler lockout. An accessible tap aerator can be checked and cleaned according to its instructions, without dismantling the installation. That household cleaning task is not equivalent to clearing a heat exchanger and does not necessarily explain 01. If the code remains, the investigation must continue into the appliance and operating conditions, with a qualified professional.

Do not try to solve the problem by raising storage tanks, installing booster pumps or adding descaling chemicals to the circuit. These are alterations or maintenance tasks requiring an assessment of the installation; they cannot be justified by this code alone. In particular, using household acids inside the boiler can damage materials and create hazards. Cleaning an accessible tap fitting and treating an internal heat exchanger are entirely different jobs.

Cold weather and extended shutdowns need careful interpretation

After a long shutdown, a lockout may occur and clear following the permitted reset. That context matters, but it does not mean there is always air in the gas pipework or authorise the user to purge gas. The safe check remains the same: use the user control and observe the result. If the appliance fails again, inactivity is not a sufficient explanation for continuing to operate it through repeated resets.

In very cold locations, protection depends on the model and installation. The reference documentation for the Victrix 26 2 I describes frost protection down to approximately −5°C and an optional specific kit for conditions down to −15°C. These are limits for that configuration, not guaranteed temperatures for every Immergas boiler. Protection also depends on meeting the operating conditions specified by the manufacturer.

A locked-out boiler, or one without the required supplies, may not provide the protection expected. If freezing is suspected, do not heat pipes with a flame, force valves or add antifreeze yourself. An installer must assess the appropriate protection and product compatibility. Code 01 during freezing weather does not by itself prove that ice is present, just as a low outdoor temperature does not rule out a different fault.

The cost depends on the diagnosis, not the display number

There is no single reliable price for resolving this lockout. It may be a one-off incident that clears after a reset, or a fault requiring tests, professional cleaning or component replacement. Prices advertised for individual parts from other versions do not represent the final repair bill. Part compatibility and labour, among other items, affect the total cost of the work.

Before authorising a repair, the estimate should clarify the diagnosis, the work included and how the callout and initial assessment are charged. Do not assume the visit charge will be deducted later: that depends on the provider’s terms. A clear estimate distinguishes the cost of finding the cause from the cost of fixing it, avoiding a decision based solely on a part advertised as the solution to 01.

The code alone is also insufficient grounds for replacing the boiler. Its age, overall condition, fault history, parts availability and the extent of the repair offer a stronger basis for deciding. If warranty or maintenance cover may apply, check the terms before commissioning work or opening the appliance. An isolated ignition lockout does not demonstrate that the boiler has reached the end of its useful life.

A recurring fault marks the limit of household checks

A precise description is more useful for an inspection than a series of repeated attempts. Recording the full model name, the displayed 01 and whether it appeared during heating or hot water demand lets you explain the problem without opening anything. It also helps to note whether it followed a supply interruption or a long shutdown. The aim is to preserve the circumstances of the fault, not to trigger further lockouts to gather information.

If there are unusual ignition bangs, smoke, a combustion smell or a carbon monoxide alarm, further testing is not appropriate. If a carbon monoxide alarm sounds or compatible symptoms occur, go outside and seek emergency assistance. The absence of a smell does not rule out this gas. In these circumstances, do not use the boiler until the situation has been assessed and its safety confirmed.

Without signs of danger, the user’s role remains specific: interpret the warning for the model, check external supply information and perform the permitted reset. If 01 persists or returns, the next step is diagnosis by an appropriately qualified engineer. The purpose of the lockout is precisely to stop operation when the expected conditions are not met; respecting that protection prevents an ignition incident from becoming a chain of unnecessary experiments.