IVGM5-8K LP2G1 hybrid inverters (fault code list, solid fault LED)
Felicity 74 error code
INV relay self-check fault: an inverter-side safety relay failed its self-check.
Likely causes
- Failed output relay
- Relay driver or control-board fault
- Welded relay contact after a surge
- Damage after repeated short-circuit trips
Checks to run, in order
- 1Restart 2-3 times and note whether the self-check passes
- 2Disconnect the backup load and retry
- 3Check the output wiring for a short
- 4Do not bypass or force the relay
Fixes
- Restart as the manual directs
- If the self-check still fails, remove the unit from service
- Book relay or control-board service
When to escalate
Code 74 is a safety-relay failure - escalate to the distributor; do not bypass the relay.
Fix it with the right tools
Check the system around the fault before replacing parts: load, battery bank, PV string and commissioning settings. If you need a second opinion, send the code and your inverter model to our team.
Before you open the inverter
- Isolate both the AC and DC sides, then confirm the display is dead before touching terminals.
- Use insulated tools and one hand where possible. DC arcs do not self-extinguish like AC.
- If you see burnt terminals, swollen cells, leaking electrolyte or a burning smell, stop and escalate instead of resetting the fault.
Questions installers ask
What does Felicity 74 mean?
INV relay self-check fault: an inverter-side safety relay failed its self-check.
How do I fix Felicity 74?
Restart as the manual directs If the self-check still fails, remove the unit from service Book relay or control-board service
When should I escalate Felicity 74?
Code 74 is a safety-relay failure - escalate to the distributor; do not bypass the relay.
Can I reset Felicity 74 myself?
Only after isolating the AC and DC sides and running the checks above. If Felicity 74 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show Felicity 74?
Felicity 74 is documented for IVGM5-8K LP2G1 hybrid inverters (fault code list, solid fault LED). Confirm the code on your own unit's display or manual before ordering parts.
More Felicity error codes
- Felicity 04Low cell voltage / over-discharge protection.
- Felicity 05PV over-current fault: the PV input current exceeded the inverter's PV input limit.
- Felicity 18PV short-circuit fault on the PV input; in the warning list the same number means battery under-voltage alarm.
- Felicity 19Battery open-circuit alarm: the inverter no longer detects a battery on its terminals.
- Felicity 20Battery SOC low alarm: the battery's state of charge has fallen to the low-SOC warning threshold.
- Felicity 21BMS communication alarm: abnormal communication between battery and inverter in non-SOC mode.
Guidance reviewed 17 October 2026 by the Mishka Energy installer team. Error codes vary by brand, model family and firmware; confirm against the manufacturer manual.
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