Solar & Electrical | Services & Systems

ABB / Power One Aurora Solar Inverter Faults and Repairs

Power One, at one point were the second ranked solar PV inverter manufacturer in the world and there are many Power One Aurora solar Inverters installed in the UK. The most popular models being the Uno PVI-3.0-TL-OUTD and the Uno PVI-3.6-TL-OUTD. Power One was purchased by electrical equipment giants ABB in 2013. As part of their purchase ABB took over the guarantee responsibilities from Power One.

As a result of their popularity we have become very familiar with diagnosing faults with Power One solar Inverters. Power One Aurora inverters, both single phase (Uno) and three phase (Trio) have an LCD display on the front of the chassis. Identifying error codes shown on the display (assuming the display is working) is usually the best place to start in diagnosing the fault and getting systems using Power One solar inverters up and running again.

NB: "E031 - Error Read V" or "Int.Error E031" This is a common error found with Power One Aurora Inverters. This is an error inside the inverter relating to damaged external relays. This error is often accompanied by a humming noise when the inverter tries to start up and presents itself just before you would typically expect the inverter to connect to the grid and start generating. Damaged relays can be replaced, however, given the age of the units that usually demonstrate this fault and the comparitively low cost of a replacement, when Power One Aurora units are out of warranty and have E031 relay failures, we recommend that the inverter is replaced.

All Solar Inverter Faults and Repairs

Solar Power System Repairs

How to Restart an ABB / Power One Aurora Solar Inverter:

Leave everything near the supply meters turned on. At the inverter there will be an AC isolator, this is used to isolate the mains/grid supply from the inverter and to prevent the inverter from feeding solar power into the electrical system. Switch the AC isolator 'off', if the inverter is running correctly you will hear a clunk inside the machine and after a while a 'no-grid', 'missing grid' warning or similar on the LCD display.

AC Isolator

Near to and or built into the solar inverter will be a method of isolating the solar (DC) supply from the inverter. Often these are black and grey and will be labelled 'DC isolator' or similar. There might be two or more of these if the system is fed by multiple strings. If there isn't a seperate DC isolation device, there will be a way to isolate the DC supply built-in to the inverter itself (often a rotary style switch underneath), turn this 'off'. When all of the lights on the solar inverter have gone out, reintroduce the AC/mains supply by turning the AC isolator 'on'. Introduce the DC supply by turning all DC isolators 'on'. This will restart the solar inverter, on the display it might show you progress during it's startup procedure. During startup is when the solar inverter carries out all of the tests needed before being able to connect the solar supply to the electrical system. If errors are found during testing they will be displayed on the screen or an indication light might come on. Make a note of any warning messages, warning lights and fault codes.

If the restart is succesful a green light will come on, sometimes flashing at first but once connected to the mains/AC supply remaining permenantly on. The LCD display will show how much power the solar PV system is generating. The solar PV system can be verified as working at the solar generation / Feed in Tariff (FIT) meter which will count on the display, the red light will pulse as it counts.

ABB / PowerOne Solar Inverter: No lights, No Display

ABB / PowerOne solar inverters are powered by the solar panels (the DC supply) and will startup at sunrise each day and shutdown at night. If you find the inverter with no lights or display working during the day, there is either a problem with the solar panels or with the inverter. Follow the shutdown and restart procedure outlined above and if the problem persists Contact us to discuss the next steps.

ABB / Power One Aurora Solar Inverter Fault Codes and Explanations:

• W001 - Sun Low - The inverter is measuring low DC voltage that it believes is due to low solar irradiance. Low irradiance (sunlight) is to be expected in the mornings and evenings and on cloudy days and the inverter, if the fault passes on it's own relatively quickly might simply be acknowledging this.

  However should there be plenty of sunlight and assuming that this is an existing installation that has been specified correctly, no changes near the installation area have been made and the system has operated before without problems. This could indicate either a problem with the solar panels or with the inverter. If you are concerned and or the fault doesn't clear itself, then we would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.

• W002 - Input UV - The inverter is measuring low DC voltage. Assuming that this is an existing installation that has been specified correctly, no changes near the installation area have been carried out and the system has operated before without problems. Anything other than a brief warning on the display at startup or shutown with this error code could indicate either a problem with the solar panels or with the inverter. If you are concerned and or the fault doesn't clear itself, then we would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.


• W003 - Grid Fail - The inverter is measuring grid (mains power) characteristics outside of it's pre-set safe operating parameters. If the situation persits then the inverter will not startup. We would advise that you Book an Engineer to identify whether the issue is with the inverter or with the mains supply.


• W010 - Fan Broken - This error indicates an internal fan failure within the inverter.


• W011 - Bulk UV - The inverter is measuring under voltage. Assuming that this is an existing installation that has been specified correctly and has operated before without problems. This could mean either a problem with the solar panels or with the inverter. We would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.


• W012 - Batt. Flat - The inverter is stating that the buffer battery inside the inverter is flat i.e. is not charging due to either a faulty battery or an internal charging error. To ensure that this is the case safely isolate the inverter and then restart it, if the time and date has reset itself to it's factory default time, reset the date and time to the correct date, then restart the system again. If the time again resets to the factory default time and date then there is either an issue with the battery which should be replaced or an internal fault within the inverter preventing the battery from being charged. Contact us to discuss how to proceed with this fault.


• E001 - Input OC - The inverter is measuring too much current from the solar panels. Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems. This could mean either a problem with the solar panels or with the inverter. We would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.


• E002 - Input OV - The inverter is measuring too much voltage from the solar panels. Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems. This could mean either a problem with the solar panels or with the inverter. We would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.


• E003 - No Parameters - This is an internal error related to the main microcontroller and communications within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E004 - Bulk Overvoltage - The inverter is measuring too much voltage from either the solar panels or the mains. Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems. This could mean either a problem with the solar panels, the mains or with the inverter. We would advise that you Book an Engineer to test the whole system AC and DC as well as the inverter.


• E005 - Comms. Error - There is a communications error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E006 - Output OC - Output Overcurrent, this fault/warning occurs when the output current exceeds the threshold that the inverter has been designed for. Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems. This fault would suggest that there is a fault within the inverter. We would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.


• E007 - IGBT SAT - This fault is an indication that the IGBT components within the inverter have become saturated. There are many factors that could contribute to this such as rapidly changing AC voltages from the grid or changing DC voltages from the solar panels. If the fault doesn't clear itself and the measured (excluding the inverter) conditions are stable it would most likely indicate an internal fault within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E009 - Internal Error - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E010 - Bulk Low - The inverter is measuring low voltage. Assuming that this is an existing installation that has been specified correctly and has operated before without problems. This could mean either a problem with the solar panels or with the inverter. We would advise that Contact us to discuss how to proceed with this fault.


• E011 - Ramp Low - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E012 - DcDc Fail - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E014 - Over Temp - The temperature inside the inverter is too hot, over the safe 60 degree limit. This could be due to a number of factors, for example 1) If the inverter is exposed to direct sunlight 2) If the inverter has been installed without adequate ventilation around the chassis which would allow excess heat to dissipate 3) The inverters components are getting too hot due to an internal component fault. If the unit isn't running hot and if after the system has been safely shutdown and restarted this condition persists then contact us


• E015 - Bulk Cap Fail - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E016 - Inverter Fail - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E017 - Start Timeout - This error might present itself when startup voltages are hovering around the threshold required to fully start the inverter in conditions of low irradiance. Low irradiance (sunlight) is to be expected in the mornings and evenings and on cloudy days and the inverter, if the fault passes on it's own relatively quickly might simply be acknowledging that power is present but not at a level sufficient enough to fully power the inverter.

  However should there be plenty of sunlight and assuming that this is an existing installation that has been specified correctly, no changes near the installation area have been made and the system has operated before without problems. This could indicate either a problem with the solar panels or with the inverter. If you are concerned and or the fault doesn't clear itself, We would advise that you Book an Engineer to test the DC side of the system including and excluding the inverter.



• E018 - Ground Fault - This error is generated when during normal operation of the inverter, a leakage current to ground/earth is detected on the DC side of the system, although it is also possible that the inverter generates the alarm E018 message due to AC leakage currents connected to the capacitive nature of the photovoltaic generator compared to ground/earth.

  For as long as the situation persits then the inverter will not startup. Earth / Ground Faults (also called Iso or Isolation Faults) often present themselves when it is raining or at times of high humidity when moisture can enter the system. These faults often clear when conditions improve but they will not get better by themselves, potentially becoming more dangerous over time.

  We would advise that you Book an Engineers visit in order to carry out a full system test, identify the source and rectify the fault. We've written more about how to identify and repair Ground Faults here: Ground Faults, Isolation Faults, RISO Faults and Insulation Resistance Faults with Solar PV Systems

• E019 - Ileak.sense Fail - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E020 - Self Test Error 1 - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E021 - Self Test Error 2 - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E022 - Self Test Error 4 - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E023 - DC In Error - Rapidly changing DC voltages due to rapidly fluctuating irradiance levels or possibly grid disturbances might be the likely cause of an E023 error. If the fault doesn't clear itself and the measured (excluding the inverter) conditions are stable it would most likely indicate an internal fault within the inverter. If after the system has been safely shutdown and restarted this condition persists contact us.


• E024 - Internal Error - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E025 - Riso Low - This error is generated when during normal operation of the inverter, a leakage current to ground/earth is detected on the DC side of the system, although it is also possible that the inverter generates the alarm E018 message due to AC leakage currents connected to the capacitive nature of the photovoltaic generator compared to ground/earth.

  For as long as the situation persits then the inverter will not startup. Earth / Ground Faults (also called Iso or Isolation Faults) often present themselves when it is raining or at times of high humidity when moisture can enter the system.

  These faults often clear when conditions improve but they will not get better by themselves, potentially becoming more dangerous over time. We would advise that you Book an Engineers visit in order to carry out a full system test, identify the source and rectify the fault. We've written more about how to identify and repair RISO Low Faults here: Ground Faults, Isolation Faults, RISO Faults and Insulation Resistance Faults with Solar PV Systems



• E026 - Vref Error - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E027 - Error Meas V - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E028 - Error Meas F - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E029 - Mid Bulk OV - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E030 - IError Meas Ileak - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E031 - Error Read V - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us. (NB: Please see the note about this error in the introduction at the top of the page)


• E032 - Error Read I - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E033 - UTH - The ambient temperature outside the inverter is too cold, under the safe -25 degree limit. If the unit isn't in such a cold environment and if after the system has been safely shutdown and restarted this condition persists then contact us.


• E034 - Interlock Fail - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E036 - V Out Avg Error - The grid voltage as measured by the inverter is too high. This may be caused by too high a grid impedance. In the final stage of the timeout, the inverter limits the power to check whether the grid voltage has stabilised into regular parameters. If the situation persits then the inverter will not startup. We would advise that you Book an Engineers visit who will be able to identify whether the issue is with the inverter or with the mains supply.


• E049 - AC FF Error - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• E057 - Vbulk Reading Error - The inverter is measuring too much voltage from the solar panels. Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems. This could mean either a problem with the solar panels or with the inverter. We would advise that you Book an Engineer to test the DC side of the system including the inverter.


• E058 - Pin Vs Pout Check Error - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.

Solar Power System Repairs

Contact us

Solar Inverter Recycling: - Recycling ABB/PowerOne Inverters

ABB/PowerOne inverters contain valuable materials such as copper and aluminium, these materials are in high demand and recycling them is significantly less energy intensive than extracting them from ore.

If you find yourself with a damaged or faulty ABB/PowerOne inverter, we will be pleased to help you recycle it.

• There is no charge for this service but all costs involved with decommissioning and transportation are covered by you.
• If you're delivering an inverter to us in person, although it's usually no trouble to arrange other days, the most convenient time for us is between 9am and 2pm on a Saturday, please let us know of your visit with an approximate time in advance.
• We do not buy or sell used inverters or used inverter parts. For UK buyers and sellers, we've found ebay to be the best place for buying used inverters and inverter parts.
• We can accept deliveries by courier at all times throughout the week but please contact us before you arrange this.
• We can also help to recycle solar panels, solar batteries and solar mounting equipment.

Solar Power System Repairs

All services

Solar Power System Testing, Servicing & Maintenance

Regular solar PV system testing, servicing and maintenance will extend the life of a solar PV system and ensure that solar panels are always operating safely and at their best, whilst maximising yields.

We offer complete safety and performance testing for solar PV power systems of any size. Includes solar panels, cables, inverters, isolators and mains connections. We provide solar power system testing and maintenance services for residential, commercial, industrial and agricultural clients across Southern, South West England and the West Midlands, with specialist experience working with farmers, developers and commercial and industrial buildings owners.

Solar Power System Testing, Servicing & Maintenance

Solar PV Inverter Replacement

If you have a faulty inverter, we offer an efficient, value for money, hassle free inverter replacement service. We offer good advice and install quality equipment with comprehensive warranty and support options. We will test the rest of the system as part of the service, take care of all hardware deliveries, record the new unit's serial number and confirm the warranty details with the manufacturer.

Our engineers work cleanly and will dispose of any unwanted boxes, faulty equipment and packaging. Many modern inverters can now use wireless home networks to transmit solar generation data to PCs, tablets and smartphones, so if you would like something like this, let us know and we will be happy to set it up as part of the installation.

Solar PV Inverter Replacement

Mains/Grid Isolation and Surge Protection

A whole house surge protector is installed to provide protection from transient overvoltages originating from the mains/grid. A whole house surge protector is installed directly inline and as close as possible to the incoming mains/grid supply meter, this allows for surge protection for all circuits and equipment including solar inverters, routers, stereos and other sensitive electrical equipment within the network. The addition of a 100Amp lockable isolator also allows for safe and convenient isolation of all electrical equipment within the network including consumer units, solar inverters, battery storage units and EV chargers from the mains/grid in one place. Surge protectors are in compliance with the recently updated 18th edition amendment 2 of BS7671.

Mains/Grid Isolation and Surge Protection

All services

Articles: Further Information, Calculators & Inverter Fault Codes

Lots of articles, calculators and technical information including links for further reading. Covering a range of topics related to the installation and maintenance of solar photovoltaic and electrical systems in the UK.

How to provide power to a house using a portable generator We look at changeover switches, the importance of earthing, generator loadings, isolating non essential loads. Where to locate the generator and how best to safely isolate the mains supply and switch to a generator supply. Solar PV, Safety & The Building Regulations Residential PV systems notifiable under Part P. Special consideration needed for Part A. A combination of serious risks for solar PV installers. Ground Faults, Isolation Faults, RISO Faults and Insulation Resistance Faults with Solar PV Systems After a number of years exposed to wind, rain, snow, ice and sometimes animals; solar panel systems can start to develop faults. The most common faults we find related to exposure are ground faults, isolation faults, RISO faults and insulation resistance faults. In this article we take a look at what these faults are, the possible causes and what steps are taken to identify and resolve them.

All articles

What Our Customers Say:

"Inverter broke down, contacted Glen, on his advice new inverter delivered within days. Glen then came and fitted new inverter within 90 mins, works perfectly. Glen is very friendly very efficient, really knows his work. Can highly recommend Glen, any other problems with solar system and Glen will be the one I call." - Carl Tyler, Salisbury

All testimonials

Case Studies

We've carried out Solar PV System design, installation, testing, repair and maintenance work on solar PV systems of all shapes and sizes all across the UK.

All case studies

We are located in Wanborough, very close to Swindon in Wiltshire, Southern England, UK. From here we service clients within a 90 minute driving radius including the towns, cities and regions below:

Swindon: Abingdon, Aldbourne, Andover, Banbury, Basingstoke, Bath, Berkshire, Bicester, Blunsdon, Box, Bracknell, Bradford on Avon, Bristol, Burford, Calne, Camberley, Carterton, Cheltenham, Chippenham, Chipping Norton, Chipping Sodbury, Cirencester, Corsham, Cricklade, Devizes, Didcot, Evesham, Faringdon, Fleet, Gloucester, Gloucestershire, Hampshire, Henley-on-Thames, Highclere, Highworth, Hook, Hungerford, Keynsham, Kingsclere, Lambourn, Lechlade, Lyneham, Maidenhead, Malmesbury, Marlborough, Marshfield, Melksham, Minety, Newbury, Oxford, Oxfordshire, Pewsey, Purton, Ramsbury, Reading, Royal Wootton Bassett, Salisbury, Shalbourne, Slough, Stow, Swindon, Tewkesbury, Thatcham, Trowbridge, Wanborough, Wantage, Warminster, Wiltshire, Winchester, Windsor, Witney, Wokingham, Worcester, Wroughton and Yate.

Contact us

Top of page

Residential - Commercial - Agricultural - Industrial