Solar Inverter Faults

Almost all inverters have some sort of on board diagnostics and show a fault code or illuminate a series LED lights to indicate there is a problem with the system.  If you suspect, there is a problem with your system then give us a call and we will happily talk you through the most basic checks and reommend a solar inverter repair or replacement if necessary.  It is always helpful but not essential for us to have the following information to hand when assessing a system over the phone:

  • Information from the inverter display, i.e. fault code, LED’s flashing
  • The make and model of inverter
  • The quantity and size in Watts of each panel

Common Reasons for Premature failure of a Solar PV/Panel Inverter

Solar inverters are routinely very reliable pieces of mainly electronic equipment with design lives of 10 years and beyond.  However, due to many reasons the service life of a solar PV inverter can be reduced significantly.  Here are some common reasons a solar inverter may fail prematurely:

Poor Selection

Load, by sizing the inverter incorrectly the inverter may have to work harder than it was designed to.  This heats up delicate electronic components and can stress them beyond the designer’s intentions which would result in an early failure.  Some studies show that heat accounts for over 50% of premature failures in electronics.


By installing a solar inverter in an unvented location with high temperatures the inverter can be exposed to unhealthy levels of heat.

Some inverters have on board fans to aid in the cooling process.  These fans can become stressed as they are overworked and again fail prematurely as a result, this has the cascading effect of shutting down or de-rating the inverter.

Blocking air circulation to the inverter or its cooling channels can have the same results as above.  Commonly Solar Inverters are located in hot loft/roof voids where summer temperatures can be significant.  Whilst most inverters can cope with these temperatures, what they can’t cope with is their cooling mechanisms being impaired.  Solar inverters require a free flow of air around the units in order to keep them cool and operating within their design parameters.  Blocking these channels of air can have a significant effect on both yield and service life due to the inverter shutting down or reducing its output by dropping into a de-rate mode.

Water and Dust Ingress.  I f your inverter is located outside, in a dirty dusty environment or worse a moist and humid area of a building then it should be rated for that location.  Humidity has been shown to contribute to around 20% of electronic failures.  Most manufacturers cater for such locations by producing an inverter which is capable of dealing with these harsh environments.  If an inverter designed for dry clean environments has been installed in an environment described above, then expect problems.  Not only may the inverter fail early it may contribute towards a dangerous situation from fire or shock risk.  Water damage can also create corrosion.  Where electronics are exposed to both hot and humid conditions 70% premature failure rates can be expected.

Agricultural Environments.  Where an inverter has been installed on or in an agricultural environment due considerations should have been made to the ability of the inverter to withstand the chemical effects of such locations.  Animals can generate large amounts of corrosive substances such as Ammonia.  Ammonia can have the effect of corroding copper alloys.  It also stands to reason that any environment with a greater than normal background of any chemical should be checked against the system components and materials to be used.  The most obvious signs of corrosion are the ones we see regularly in the form of rust.  The less obvious ones are chemically corrosive and may not be seen from a courser glance at the external case of an item and may only be visible from an internal inspection.

Overvoltage – A/C

It is quite common in the UK to see high grid voltages way in excess of the perceived 240V line voltage we have historically transmitted.  This is mainly due to weak networks with settings on sub station transformers turned up to maximum to hold voltages within the grid defined limits at the far end of a long cable run.  This means that supplies nearer to the sub station transformer can expect high grid voltages, in particular at times of low local usage as the voltage rises with low demand.  This can result in Solar inverters regularly dropping out on their over voltage settings which they must have ironically to stop the grid voltage rising above the grid upper limits.  This has two effects on the Solar Inverter, firstly there can be significant losses due to the inverter being off line until the grid voltage drops back into limits and secondly the inverter is being over stressed by high grid voltages.  This can show up as early failures of the over voltage relay on board the inverter.  Some inverters such as the later Fronius and SMA items can have their settings altered by the use of a manufacturer specific piece of software or by accessing the inverters on board settings and raising the threshold.  This must only be carried out by a competent person and in some cases may require approval from the local District Network Operator, (DNO).  C Gascoigne Ltd. have access to most solar inverter software and the relevant consents required to access such settings.

Mechanical Damage

Mechanical damage can sometimes be quite obvious, especially where significant impact damage has taken place.  Sometimes though what can seem like a small none relevant indent can have pronounced effects on such items as seals designed to keep out moisture and gasses.  Where equipment is located in areas with increased risk from mechanical stresses such as where fork trucks and machinery is in operation then it is advised that regular inspection of these items is carried out.


Failure rates of electronics due to vibrations has been proven to be significantly greater than those which are not exposed to such conditions.  Surveys show that around 20% of failure rates of electronics is down to excessive vibrations.  Any surface where a Solar inverter is mounted should be free from vibrations.


Any solar inverter mounted at ground level is at risk from vandalism.  As a rule of thumb, all solar systems should be kept away from public areas.  Where vandalism is a real threat then precautionary measures should be put in place.