IQ8MC/IQ8AC/IQ8HC Installation and Operation Manual
20 © 2023 Enphase Energy Inc. All rights reserved. September 2023
IOM-00029-1.0
5. Troubleshooting
Follow all the safety measures described in this manual. Competent personnel can use the
following troubleshooting steps if the PV system does not operate correctly.
WARNING: Risk of electric shock. Do not attempt to repair the Enphase microinverter; it contains
no user-serviceable parts. If it fails, contact Enphase Support
to obtain a return merchandise
authorization (RMA) number and start the replacement process.
5.1 Status LED indications and error reporting
The following section describes LED indications.
LED operation
Flashing green
Normal operation. AC grid function is normal and there is communication with
the IQ Gateway
The AC grid is normal but there is no communication with the IQ Gateway
The AC grid is either not present or not within the specification
Solid red
There is an active DC Resistance Low, Power Off condition. To reset, refer to
the IQ Gateway Installation and Operation Manual at:
https://enphase.com/en-gb/installers/resources/documentation.
If the problem persists, measure resistance between PV+ to EARTH and then PV-
to EARTH on the PV module and then inverter. Anything less than ~7 kΩ will
trigger the DC Resistance Low, Power Off condition. Usually, the value is in MΩ
on the inverter or PV module. Swap out faulty PV module or microinverter
The status LED on each microinverter lights green about six seconds after DC power is applied. It remains
lit solid for two minutes, followed by six green flashes. After that, red blinks indicate that no grid is present
if the system is not yet energized.
Any short red blinks after DC power is first applied to the microinverter indicate a failure during
microinverter startup.
DC Resistance Low – Power Off condition
For all IQ8 Series Microinverters, a solid red status LED when DC power has been cycled indicates the
microinverter has detected a DC Resistance Low – Power Off event. The LED will remain red, and the
fault will continue to be reported by the gateway until the error has been cleared.
An insulation resistance (IR) sensor in the microinverter measures the resistance between the positive
and negative PV inputs to the ground. If either resistance drops below a threshold of 7kΩ, the
microinverter stops power production and raises this condition. This may indicate defective module
insulation, defective wiring or connectors, moisture ingress, or a similar problem. Although the cause
may be temporary, this microinverter condition persists until the sensor is manually reset.
An IQ Gateway is required to clear this condition. The condition clears on operator command unless its
cause is still present.
If a microinverter registers a DC Resistance Low-Power Off condition, you can attempt to clear this
condition. If the condition does not clear after you perform the following procedure,
contact Enphase Support
.
Follow the steps below to send a clear message to the microinverter. Note that the condition will not clear
after the sensor reset if the cause of the failure is still present. If the condition persists, contact your
installer.
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