Immergas boiler error codes: meanings and safe solutions

Error 01 on an Immergas boiler usually indicates an ignition failure; 10 means insufficient pressure; and 27 points to inadequate water circulation. These are different conditions and need different responses. Before pressing Reset, note the number and model: the code identifies an abnormal condition, not a confirmed faulty part. If you smell gas, see fumes indoors or notice signs of unsafe combustion, do not reset the boiler. Seek emergency assistance from a safe location.

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

The model matters as much as the number on the display

Immergas uses numerical codes on many boilers, but that does not make its fault listings universal. Victrix Tera, Maior TT, Omnia and the different Eolo boilers share some warnings and differ on others. Always check the meaning against the manual for the exact version, including its full model designation. Similar names do not guarantee identical controls, accessories or reset procedures.

You can find the model in the installation documents or on an accessible external label. There is no need to remove the casing. A photograph of the display and identification label helps explain the problem, particularly if the warning later disappears. It also matters whether you have lost heating, hot water or both: the boiler’s behaviour provides context for the code and helps narrow down the diagnosis.

The tables below separate warnings associated with Victrix Maior TT and Tera from differences documented for Omnia and Eolo. They provide a reference, not confirmation that every generation supports every code. Any cause shown is a possibility that needs checking: no table entry justifies replacing parts by trial and error or working inside the boiler.

Warnings on Victrix Maior TT and Tera boilers

These ranges can report ignition lockouts, circulation problems, sensor faults and communication failures. Their effects vary: some stop the appliance, while others reduce output or clear when normal conditions return. The appropriate response depends on whether it is a lockout, warning or automatically clearing condition, as well as the instructions for the specific boiler.

The cause listed is not necessarily the only one. Loss of flame signal, for example, may involve the supply, flame detection or combustion; a sensor warning can also arise from its connection. The action column distinguishes what the user can observe safely from checks that need a qualified professional, without dismantling components or taking electrical measurements at home.

Omnia and Eolo differences can change the interpretation

The Victrix Omnia includes warnings that should not automatically be applied to every Tera or Maior TT. These include keypad problems, sensor consistency issues and combustion operating limits. Eolo boilers also include variants with different monitoring systems. That is why the same brand does not guarantee the same diagnosis, especially for codes involving flue systems or electronics.

Code 11, associated with the flue pressure switch on certain Eolo models, is not equivalent to fan code 16 on other ranges. It does not prove that the pressure switch has failed, either: the boiler may be detecting an unsafe flue condition. For code 28, described as leak detection on certain Eolo models, confirm the exact scope of the warning in that version’s manual rather than applying it to every Immergas boiler.

The available information about P07 mixes a requested-speed description with generic fault claims. That combination does not establish that it is a lockout on every model. A parameter screen can display operating information without reporting a defective part. Do not change settings or buy a fan because of P07 before identifying the appliance and the screen displaying it.

Error 01 may allow one reset, not repeated attempts

Code 01 appears when ignition does not complete correctly. It may occur after a long period without use, but supply, ignition, flame detection and combustion problems can also cause it. If there are no danger signs and the manual permits it, you can try one reset using the control panel. The control may be a button or a selector; there is no single action that applies to every boiler.

If the lockout returns, that result is useful: the reset did not resolve the underlying condition. Pressing again does not distinguish between an electrode, valve, supply or control problem. Some versions display 08 after five resets within one hour and prevent further attempts for 60 minutes. That limit is a safeguard, not a number of attempts to work through.

Codes 38 and 43 describe isolated or repeated losses of flame signal, while 20 indicates a flame signal when none should be present. They are not interchangeable versions of 01. If they recur, or occur alongside harsh ignition or abnormal noises, stop trying to start the boiler. The inspection needs to cover combustion and its monitoring, rather than assuming that cleaning or replacing an electrode will be enough.

Low pressure and poor circulation are different problems

For error 10, the accessible check is to read the pressure gauge when the system is cold. Many boilers in these ranges use between 1 and 1.5 bar when cold as a reference, but the manual and the particular installation take precedence. The documentation reviewed also mentions narrower ranges of 1 to 1.2 bar; these should not be treated as a universal rule.

A low reading suggests insufficient pressure but does not explain why it has fallen. There may be a visible leak, an internal loss or a problem elsewhere in the installation. If the gauge appears normal but the code remains, that does not prove the pressure sensor is faulty: the gauge reading and pressure detection need professional comparison. Do not buy a sensor simply because the needle appears to be in the right place.

Code 27 means insufficient circulation; 60 indicates a blocked circulation pump; and 61 reports air in it. The system can have pressure without water moving as the boiler needs it to. You can observe which radiators stay cold and whether there are gurgling noises, but do not open the pump or try to free it. Filling and bleeding procedures are not included here either: they involve working on a pressurised water circuit.

Repeated topping up does not resolve an ongoing loss, even if the warning temporarily disappears. Before approving a repair, it is worth establishing whether the cause lies in the boiler or the heating installation. That distinction helps avoid paying for a part that will not solve the problem. Pressure changes between cold and hot conditions, recorded without adjusting anything, are more informative than a series of restarts.

Flue, fan and combustion warnings mark the limit of home checks

Warnings 03, 16, 29 and 96, alongside 11 on certain Eolo models and 92 on Omnia, involve air, ventilation or flue functions. An obstruction and a sensor fault can cause similar symptoms. From ground level, without any risk of falling, you can look at the external terminal and report a visible object, ice or damage. Do not dismantle it, insert tools or access roofs.

Codes 77, 78, 79, 84, 87 and 88, along with Omnia combustion warnings, require specialist instruments and expertise. A reference to valve control on the display does not prove the valve is the sole cause. Do not adjust parameters, alter the supply or test components. Gas circuit work and calibration belong to a qualified technician, even when the boiler still produces hot water.

The reduced output associated with 47 or 84 is not permission to keep using the appliance indefinitely. It may be a protective response from the control system. Persistent limitation needs investigation, even if the shower still works. If you smell gas, avoid flames and electrical switches, move to safety and contact the appropriate emergency service. If symptoms suggest exposure to combustion gases, leave the premises and seek urgent help.

Sensors, controllers and power supply need different interpretations

Codes 05, 06, 23 and 29 refer to temperature sensors at different points. In simple terms, an NTC sensor changes its electrical behaviour with temperature. The warning may involve the sensor or its connection, so a sensor fault does not automatically identify the replacement part. Measurements and wiring inspections are outside the scope of household checks.

Code 06 deserves attention if the water becomes excessively hot or its temperature fluctuates. Some versions may continue with reduced performance and altered protection functions. Do not repeatedly test the temperature with your hand or dismiss fluctuations because water is still flowing: the risk of scalding means that use should stop until operation has been checked.

Warnings 31, 36 and 51 concern communication, not necessarily the burner. It is reasonable to see whether the controller display is working, check batteries that users are allowed to replace and observe whether the boiler panel responds. Do not open receivers or alter electrical connections. For errors 37 or 59, power supply quality also needs consideration; tell a qualified electrician if other appliances are affected.

A calibration request does not prove the board has failed

Warnings 62 and 72 request full or quick calibration. They can appear after changes to electronics or parameters and require a professional procedure. If the boiler worked before an intervention and the warning appeared immediately afterwards, tell the person who carried out the work. Buying another board before checking calibration is not justified; the configuration required by that model needs checking too.

A similar principle applies to Omnia code 70, associated with interchanged flow and return sensors: appearing after a repair points the inspection towards the recent work, without proving the sensors are damaged. Codes 80, 98 and 99 do not justify electronic replacement on their own either. A general lockout provides little localisation; diagnosis needs history and testing, not just the last number displayed.

Opening the casing to find a part number adds unnecessary risk and can complicate the assessment of earlier work or contractual cover. If the appliance is under warranty or a maintenance agreement, check the conditions before commissioning outside work. External identification is usually enough to start an enquiry; the professional can verify internal references when appropriate.

Repair decisions should follow the cause, not the code

Before an inspection, keep a photograph of the warning, the full model name, the observed pressure and when the fault occurs: when a tap opens, when heating is requested or after several minutes. A recent power cut, repair or long period without use is also relevant. This context helps distinguish a one-off incident from a recurring pattern without carrying out tests that could make the problem worse.

The display cannot tell you the repair cost. The same warning may lead to a configuration correction, a connection repair or component replacement. Before accepting the work, the quotation should distinguish diagnosis, call-out charges, labour and materials, and explain whether the visit charge is credited against the repair. The price of a spare part is not the repair price, particularly when calibration and combustion checks are required.

Whether to repair or replace depends on overall condition, previous faults, parts availability and the total cost compared with an equivalent installed appliance. One code cannot establish that a boiler has reached the end of its life, just as a successful reset does not prove a recurring cause has gone away. The soundest approach is to confirm the cause before spending money or continuing use: observe externally, respect safety protections and leave internal work to a qualified professional.