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How To Troubleshoot an Inoperable Enphase Microinverter

A flashing red LED indicates the AC grid is either not present or not within specification. The microinverter does not sense that the utility grid is within voltage/frequency specifications, and cannot produce power until this is resolved. To troubleshoot an inoperable Enphase microinverter, follow the steps in the order shown to diagnose your solar system. 

* WARNING: Risk of electric shock. Always de-energize the AC branch circuit before servicing. Never disconnect the DC connectors under load.

* WARNING: The Enphase Microinverters are powered by DC power from the PV modules. Make sure you disconnect the DC connections and reconnect DC power and then watch for the solid green about six seconds after connection to DC power. 

Troubleshooting an Enphase System - 15 Steps:

1. Make sure AC breakers and disconnects are closed.

2. Check the connection to the utility grid and verify that the utility voltage is within allowable ranges.

3. Verify that AC line voltages at all solar power circuit breakers at the load center and subpanels are within the ranges shown in the following table.

4. Verify that AC line voltage at the junction box for each AC branch circuit is within the ranges shown in the following table:

240 Volt AC, Single Phase

208 Volt AC, Three Phase

L1 to L2

211 to 264 VAC

L1 to L2 to L3

183 to 229 VAC

L1, L2 to neutral

106 to 132 VAC

L1, L2, L3 to neutral

106 to 132 VAC

5. Using an Enphase disconnect tool, disconnect the AC cable for the microinverter in question from the Engage Cable. 

6. Verify that utility power is present at the microinverter by measuring line to line and line to neutral at the Engage Cable connector.

7. Visually check that the AC branch circuit connections (Engage Cable and AC connections) are properly seated. Reseat if necessary. Check also for damage, such as rodent damage.

8. Make sure that any upstream AC disconnects, as well as the dedicated circuit breakers for each AC branch circuit, are functioning properly and are closed.

9. Disconnect and re-connect the DC PV module connectors. The Status LED of each microinverter will light solid green a few seconds after connection to DC power and then blink green six times to indicate normal start-up operation about two minutes after connecting to DC power. The LED subsequently resumes normal operation if the grid is present. See page 27 of the Installation and Operation Manual for normal LED operation

10. Attach an ammeter clamp to one conductor of the DC cables from the PV module to measure microinverter current. This will be under one Amp if AC is disconnected.

11. Verify the PV module DC voltage is within the allowable range shown in “Specifications” on page 38 of the manual

12. Swap DC leads with a known good, adjacent PV module. If after checking Enlighten periodically (this may take up to 30 minutes), the problem moves to the adjacent module, this indicates that the PV module isn’t functioning correctly. If it stays in place, the problem is with the microinverter. Call Enphase Customer Support for help in reading the microinverter data and for help in obtaining a replacement microinverter, if needed.

13. Check the DC connections between the microinverter and the PV module. The connection may need to be tightened or reseated. If the connection is worn or damaged, it may need replacement.

14. Verify with your utility that line frequency is within range.

15. If the problem persists, contact Customer Support at enphase.com/en-us/support/contact.