Free diagnostic tool

Solar Inverter Fault Checker

Answer 5 quick questions to find out whether your solar inverter has likely failed — or if the problem is something else entirely.

Published August 2026. Updated quarterly. Source: MCS installation standards, manufacturer fault-code databases.

Quick check (no JavaScript needed)

Display blank? → Check DC isolator is ON. If ON and still blank: likely inverter fault.
No lights at all? → Check AC isolator + consumer unit MCB + DC isolator. If all ON: likely inverter fault.
Display on but 0W in daylight? → Inverter powered but not converting. Likely inverter fault.
Error code showing? → Confirmed fault. Note the code for diagnosis.
Generation meter still counting up? → Inverter IS working. Problem is likely monitoring/meter, NOT inverter.

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Energy advisors, housing associations and solar blogs — you are welcome to link to or embed this checker. Please use the following attribution:

<a href="https://inverterreplacementscotland.co.uk/inverter-fault-checker">Solar Inverter Fault Checker by Scottish Energy Efficiency</a>

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