Heat Pump Error Codes

An error code alone isn't a diagnosis — it's a direction in which to look for the cause. The same code from two different manufacturers can mean a similar, but not identical, problem. However, knowing how a code is structured and its general meaning lets you quickly decide whether a simple restart is enough or whether a technician is needed.

What heat pump error codes mean

Heat pump error codes are an expression of the unit's control board self-diagnostic system. The control board continuously monitors sensors — temperature, pressure, flow, voltage and current. When a value exceeds allowed limits or a sensor doesn't respond, the board registers an error and displays a code on the indoor unit's display, the remote control panel, or in an app.

The code helps the technician save diagnostic time. That's why, when requesting a repair, always state the specific code — the technician can prepare, bring likely spare parts, and complete the repair in one visit. This also reduces the risk of a wrong conclusion and avoids the cost of repeat diagnostics.

Different manufacturers use different coding systems. Daikin, Mitsubishi, Panasonic, Nibe and Thermia each apply their own code logic, although the underlying pattern is broadly similar letters-and-numbers. These differences are important to keep in mind when comparing information from different sources.

Most common error codes

Here's a general overview of the most commonly encountered error code patterns in modern heat pumps. These are general patterns — always check the exact meaning of your specific unit's code in its user or service documentation.

Some codes appear in combination — for example, "E3 + P2" indicates a simultaneous refrigerant and pressure problem, which strongly points to a leak. A technician uses such code combinations to narrow down the diagnosis faster. This information is also useful for you, as it helps you better understand whether the situation is urgent.

What to do when an error code appears

In most cases there's no need to urgently shut down the unit, but it's important to respond correctly. A sequence that works for most manufacturers:

Don't ignore error codes that return or don't clear. They warn of problems that can gradually worsen and affect other system components — and the repair will become much more expensive.

Manufacturer-specific codes

Each manufacturer uses its own error-coding system, and in some cases this even differs across model lines from the same manufacturer. That's why it's important for the technician to know which system they're working with, to avoid drawing the wrong conclusions.

• Daikin — uses alphanumeric codes (e.g. E01, A1), often with additional sub-codes.
• Mitsubishi — two- or three-character codes shown on the control panel, considered one of the more detailed systems.
• Panasonic — a code series that differs depending on whether it concerns heating, cooling or hot water.
• Nibe — numeric codes, also with an LED indicator blink pattern in older models.
• Thermia — a combination of color and error code on floor-standing and compact units.

The technician needs not only the manufacturer and model, but also the year, commissioning date and, if available, the current software version. All of this information is resolved in the request — so it's worth writing down what you know before filling in the form. A detailed request lets the specialist prepare and resolve the problem in a single visit, which might otherwise require repeat intervention.

Request a repair through the heat pump repair page if you'd like to be matched with a suitable specialist in your region who services your manufacturer's units.

When an error code requires urgent repair

Some error codes are warnings intended for preventive action — such as a filter-cleaning reminder or a seasonal maintenance reminder. You can keep using the unit with these, but maintenance should be scheduled promptly.

Other codes indicate a problem that can lead to further damage or even a hazardous condition. Be especially cautious with these patterns:

• Compressor-related codes (e.g. E2, P1, P2) — continuing operation can cause the compressor to burn out completely, which is the most expensive component of the unit.
• Refrigerant pressure codes (E3, P1, P2) — indicate a leak. Prolonged operation with low refrigerant damages the compressor and increases electricity consumption.
• Electrical codes (U1, U2) — a voltage or power supply fault can damage the control board, which is a costly repair item.
• Sensor codes that don't clear after a restart — indicate a mechanical sensor fault that won't disappear without repair.

When you request a repair through this platform, we will contact you for your region. and the chosen system type. The specialist will contact you within 5 minutes to clarify the nature of the problem and arrange a visit. This is the only transfer of information that takes place, apart from the contact method you provide yourself.