Air source heat pumps are popular for providing energy-efficient heating, but can experience error codes that require repair. In this article, we’ll discuss the 10 most common error codes for the three most popular air source heat pump models in the UK, with information on occurrence, cost to fix, and whether DIY or an engineer is required. We’ll also cover tips on preventing issues with regular maintenance and choosing a reputable installer and service provider.
10 most common error codes for air source heat pumps
Low pressure/loss of pressure in the refrigeration circuit
This error code indicates that there is low pressure or a loss of pressure in the refrigeration circuit, which can be caused by leaks, faulty valves, or other issues.
High pressure in the refrigeration circuit
This error code indicates that there is high pressure in the refrigeration circuit, which can be caused by a variety of issues such as a malfunctioning compressor or a blockage in the refrigeration circuit.
Malfunction of the compressor
This error code indicates that there is a malfunction in the compressor, which can be caused by a variety of issues such as electrical faults, mechanical issues, or refrigerant leaks.
Low pressure switch tripped
This error code indicates that the low pressure switch has been tripped, which can be caused by low refrigerant levels, leaks, or other issues.
High pressure switch tripped
This error code indicates that the high pressure switch has been tripped, which can be caused by issues such as a malfunctioning fan, a clogged air filter, or a blockage in the refrigeration circuit.
Malfunction of the fan motor
This error code indicates that there is a malfunction in the fan motor, which can be caused by a variety of issues such as electrical faults, mechanical issues, or a buildup of dirt or debris on the fan blades.
Malfunction of the expansion valve
This error code indicates that there is a malfunction in the expansion valve, which can be caused by issues such as a buildup of dirt or debris, or a malfunctioning solenoid valve.
Malfunction of the 4-way valve
This error code indicates that there is a malfunction in the 4-way valve, which can be caused by issues such as electrical faults or mechanical issues.
Malfunction of the reversing valve
This error code indicates that there is a malfunction in the reversing valve, which can be caused by issues such as electrical faults or mechanical issues.
Electrical supply voltage problems
This error code indicates that there is a problem with the electrical supply voltage, which can be caused by issues such as a faulty circuit breaker, loose wiring, or electrical interference.
ASHP Most common faults and cost to fix
| Error Code | Common Occurrence | Cost to Fix | DIY or Engineer Required |
|---|---|---|---|
| Low pressure/loss of pressure | Common | £100 – £500 | Engineer |
| High pressure | Common | £100 – £500 | Engineer |
| Malfunction of the compressor | Common | £200 – £1,500 | Engineer |
| Low pressure switch tripped | Common | £100 – £500 | Engineer |
| High pressure switch tripped | Common | £100 – £500 | Engineer |
| Malfunction of the fan motor | Common | £100 – £500 | Engineer |
| Malfunction of the expansion valve | Common | £100 – £500 | Engineer |
| Malfunction of the 4-way valve | Less Common | £100 – £500 | Engineer |
| Malfunction of the reversing valve | Less Common | £100 – £500 | Engineer |
| Electrical supply voltage problems | Less Common | £100 – £500 | Engineer |
the cost to fix may vary depending on the severity of the issue and the make and model of the air source heat pump. it is also important to note that attempting to fix an air source heat pump yourself can be dangerous and may cause further damage to the system. It’s recommended to contact a qualified engineer to diagnose and fix any issues with your air source heat pump. The cost to fix will depend on the severity of the issue and the type of repair required, and may vary based on your location and the service provider you choose.
Air source heat pump not heating water
If you have an air source heat pump and are experiencing a common issue of not heating water, there could be a few potential causes. One common cause is a faulty thermostat, which could be preventing the heat pump from turning on properly. Another possible cause could be a clogged filter or coil, which can prevent the heat pump from functioning efficiently. Additionally, low refrigerant levels or a malfunctioning compressor can also cause issues with water heating. If you’re experiencing any of these issues, it’s best to consult with a professional technician to diagnose and address the problem.
Mitsubishi ASHP error codes
Mitsubishi air source heat pumps are reliable and efficient, but like any complex system, they can experience errors from time to time. Some of the most common error codes that you may encounter with a Mitsubishi air source heat pump include E6, which indicates an issue with the indoor fan motor, and E7, which indicates a problem with the outdoor fan motor. Other common error codes include E9, which indicates a problem with the indoor heat exchanger sensor, and E0, which indicates a communication error between the indoor and outdoor units. Remember that each error code can have multiple potential causes, so it’s always best to consult with a professional to accurately diagnose and repair the issue.
Vaillant ASHP error codes
Vaillant are also a popular and reliable air source heat pump manufacturer. Some of the most common error codes that you may encounter with a Vaillant air source heat pump include F.28, which indicates an issue with the ignition or gas supply, and F.29, which indicates a problem with the flame sensor. Other common error codes include F.32, which indicates low water pressure, and F.33, which indicates a problem with the circulation pump
Remember that regular maintenance and servicing of your air source heat pump can help prevent these common error codes from occurring. Regular maintenance can include things like cleaning air filters, checking refrigerant levels, and inspecting the system for leaks or other issues. Many manufacturers recommend annual or bi-annual servicing to ensure the efficient and safe operation of the system.
Also, in the first place, choose a reputable and experienced installer and service provider for your air source heat pump. A qualified installer, who will be MCS certified, can ensure that the system is properly sized and installed, and can provide advice on the best practices for operating and maintaining the system. Similarly, a qualified service provider can diagnose and fix any issues that arise, and can provide advice on the best practices for maintaining the system over time.
