Thermor heat pump errors: Áurea and Aeromax fault codes

A G11 alert on a Thermor Áurea means the water pressure is too low; W.7 on an Aeromax VM R290 indicates no water in the tank or an open connection in the corrosion protection system. These are not equivalent faults and require different responses. Interpreting an alert starts with identifying the model and complete error code: you can check the display, scheduling and accessible air openings, but internal electrical, hydraulic and refrigerant work must be left to a qualified technician.

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

Áurea and Aeromax require different diagnoses

Thermor sells appliances with different functions and control systems. The Áurea, Áurea Duo and Áurea Compact models covered here belong to a heat pump family designed for space heating and, depending on configuration, domestic hot water. The Aeromax VM R290 is a wall-mounted heat pump water heater. This matters because each family has its own code table, even though both extract energy from the air.

The Áurea codes below apply only to the R32 configuration associated with hydraulic module 024252 and outdoor units 750761, 750795, 750762 and 750763. The Aeromax codes apply specifically to the VM R290 version. They must not be extended without checking to Aeromax 4, Aeromax 5, Concept, Split, Alféa or Aerolia Duo. The product name alone may not be enough: the reference on the rating plate helps identify the exact version.

A photograph of the display preserves information that is lost when only the number is written down. On Áurea, G6.17 does not mean the same as G6.27; on Aeromax, P.30.1 and P.30.2 are not interchangeable either. Keep the letters, dots and suffixes when reporting an alert. Generic tables that automatically assign numbers 01, 02 or 03 to sensors cannot diagnose every Thermor appliance and may lead to buying the wrong replacement part.

Áurea alerts from the hydraulic module

The hydraulic module monitors temperatures, pressure, water circulation and communication between components. Its messages may indicate an operating condition or a measurement problem. For example, G11 reports low pressure, whereas G9 indicates a fault with the sensor that measures it. This distinction prevents a faulty reading being mistaken for low water and avoids work on the circuit without an adequate diagnosis.

The table separates the meaning of each message from its possible causes. A sensor error or interrupted communication does not prove that the main component has failed: a connection problem may also be responsible. Checking this requires access to the appliance and is a professional task. From outside, the useful information is the alert and accompanying symptoms, such as no heating, no hot water or visible water leakage.

Communication messages call for an additional precaution: they do not prove a circuit board has failed. An illuminated display showing G29 or G46 does not establish which board needs replacing, just as a phone with no signal is not necessarily broken. Buying electronics before checking the power supply, connections and associated components can add expense without resolving the lockout.

G6.XX identifies an outdoor unit issue

On these Áurea models, G6.XX is a family of messages rather than a single diagnosis. The characters after the dot identify the specific issue: it may involve a sensor, fan, compressor, pump or water flow. It is therefore essential to record the complete suffix, particularly when the appliance alternates between screens or displays the message after attempting to start.

Some codes describe an activated protection function, not a component that automatically needs replacing. G6.18 indicates discharge temperature protection, while G6.20 indicates abnormally low refrigerant circuit pressure. The latter is not the water pressure referred to by G11. Adding water to the heating circuit does not resolve a low refrigerant pressure protection event and may create a second problem.

The emergency mode provided for this family allows heating through the electric backup when the outdoor unit fails. Activate it only through the designated user controls, following the model instructions and without accessing technical menus. It does not repair the fault or make continued operation acceptable if there are leaks, burning smells, electrical trips or abnormal noises.

Aeromax VM R290 separates water, heat pump and scheduling alerts

The Aeromax VM R290 displays messages with letters and numbers, usually accompanied by Err. W alerts concern the tank, its measurements or power supply; P alerts relate to the heat pump, and H.15 concerns the clock. This classification is useful, but the letter does not determine severity: some messages stop all heating, while others allow the electric backup to operate.

W.7 needs particular care because it can mean no water in the tank or an open connection in the ACI corrosion protection system. It does not prove on its own that the tank is empty. Nor does water flowing from a tap rule out an ACI fault. With this alert, do not force the heater to run or interfere with the anode, its wiring or the tank connections.

The −40 °C and 125 °C limits associated with P.21 and P.22 are thresholds for detecting an abnormal reading, not permitted ambient operating temperatures. P.40 should not be interpreted using a generic range taken from another Aeromax either. The valid range depends on the version and installation conditions; a cold room or unsuitable air intake may explain the alert without proving a component has failed.

Low pressure cannot be fixed by clearing the message

With G11, you can read the pressure shown by the appliance and look for visible damp patches or drips around pipes and heat emitters without dismantling anything. There is no single figure that applies to every installation: configuration and height both matter. Any adjustment must follow the pressure specified for that installation, not a value found in a table for another heat pump.

Restoring the water level or reducing excessive pressure means working on a pressurised circuit. Even when the message describes insufficient water, this is where household checks end: filling and draining are professional tasks. Do not open filling valves, air vents or safety valves to try to clear G11 or G12, especially if you do not know exactly which component you are operating.

If the pressure falls again after correction, that recurrence is important evidence. Each episode should not be treated as an unrelated event, nor should repeated topping up replace investigation of the cause. A leak or another hydraulic problem may need diagnosis. Recording when the pressure changes, with the system cold or running, is more useful than repeatedly resetting the appliance and losing the alert history.

Cold exhaust air and long heating times do not always mean a fault

A heat pump water heater extracts heat from the air and transfers it to the water. It may therefore discharge colder air while operating: this is a consequence of the process, not proof that it is cooling the tank. A fault becomes more likely when there is a persistent code or reduced performance, not simply because the outgoing airflow feels cool near the grille.

On an Aeromax, you can check whether objects or dust are blocking the external grilles and clean only surfaces or filters identified in the manual as user-accessible. The appliance must be stopped, and cleaning must follow its instructions. Do not put tools between the fan blades or remove covers to reach the evaporator. Internal cleaning, incorrectly configured ducts and structural vibration require installation or maintenance checks.

P.30.1 provides a specific piece of information: the appliance has detected a heating time exceeding 25 hours. This does not automatically mean the compressor has failed. Continuous water use, a leak or heat transfer problems can play a role. Noting repeated showers, a dripping tap or recent changes in usage helps diagnosis. Persistent ice or a stationary fan with an active alert, however, does not justify applying heat or moving the blades yourself.

Continued hot water can conceal a heat pump fault

The backup element may maintain hot water when the heat pump stops. On the Aeromax VM R290, several P alerts allow this alternative operation; Áurea offers emergency mode for certain outdoor unit problems. Therefore, hot water does not mean the fault is fixed. The appliance may continue meeting demand while no longer using the heat pump operation that normally reduces electricity consumption.

In practice, relying on electric backup for a long period can increase running costs compared with normal heat pump operation. A reliable amount cannot be calculated without knowing the power, running hours, demand and electricity tariff. It is important to distinguish continued service from efficient operation: having heating or hot water gives you time to arrange inspection, but does not turn a temporary workaround into a repair.

W.10 adds an important detail: on this Aeromax, emergency backup can heat to 62 °C while the display stops updating. Do not treat a frozen reading as confirmation of the actual water temperature. If this message appears, do not test the temperature with your hand, and have a professional check communication. Electric backup availability does not remove the risk of scalding or make a display reliable when it is no longer receiving information.

An accurate diagnosis avoids unnecessary parts and expense

H.15 is the clearest example of a check that can be resolved through the normal controls: setting the date and time restores scheduling after the clock setting is lost, including after a power cut lasting more than an hour. If the alert returns, the loss of the setting needs investigation. W.19, by contrast, is not necessarily resolved by setting a schedule: it indicates power interruptions affecting the ACI system, and electrical correction is a professional task.

Only reset the appliance when the model instructions provide for it. First, keep a photograph of the message and its context. Repeatedly cutting power to hide an alert does not establish that the appliance is working properly and may be counterproductive on an Aeromax with powered corrosion protection. Do not remove covers to reset thermostats or enter installer test menus: clearing the alert does not identify its cause.

A code alone cannot establish a repair price or determine whether replacing the appliance makes financial sense. A poor connection, a sensor fault and a compressor problem have different implications, even when their symptoms look similar. Before authorising a replacement part, the quote should identify the confirmed fault, the work included and whether diagnosis or a call-out is charged separately. Replacement decisions depend on overall condition and the confirmed repair, not age alone.

If the appliance may be under warranty, keep the paperwork and check the terms before commissioning work or buying parts. It is not accurate to say that opening a cover always invalidates every form of cover, but neither should intervention be assumed to have no consequences. A sound decision starts with the model, complete code and documented checks. These details help prevent a limited alert from turning into a repair based on guesswork, without taking risks or assuming a fault that has not yet been demonstrated.