Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU INVERTER BOARD FAIL Error Fix: Inverter Board Failure

The inverter/IPM board in outdoor unit has failed. Converts AC to variable-frequency DC for compressor. Symptoms: H6 error, outdoor unit not starting. Fails due to power surges, voltage irregularities, or moisture. Costly repair — boards $200–$600. Consider surge protector.

critical2 fixes available✨ Free fix available

Quick Answer

Error INVERTER BOARD FAIL on the Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU means: Inverter Board Failure. The top-ranked community fix is “Replace the Inverter Board with Surge Protection Installation” (hard difficulty, ~150 min, DIY cost: $20-$30). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · mini split

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many mini split repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $400-$600.

Other Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU Error Codes

CONDENSATE DRAIN BLOCK

Condensate Drain Blockage / Water Leak

2 fixes

Compressor High Pressure Protection

2 fixes

Indoor Coil Anti-Freeze Protection

2 fixes

Compressor Low Pressure Protection

2 fixes

Compressor Discharge Temperature Protection

2 fixes

Compressor Overcurrent Protection

2 fixes

Communication Error — Indoor/Outdoor

2 fixes

Indoor Fan Motor Fault

2 fixes

People Also Ask About Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU Error INVERTER BOARD FAIL

What does error code INVERTER BOARD FAIL mean on a Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU?

Error code INVERTER BOARD FAIL on the Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU means: Inverter Board Failure. The inverter/IPM board in outdoor unit has failed. Converts AC to variable-frequency DC for compressor. Symptoms: H6 error, outdoor unit not starting. Fails due to power surges, voltage irregularities, or moisture. Costly repair — boards $200–$600. Consider surge protector.

How do I fix error code INVERTER BOARD FAIL on my Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU?

The most successful fix is "Replace the Inverter Board with Surge Protection Installation" (hard difficulty, ~150 minutes). Estimated DIY cost: $20-$30. HomeMD has 2 community-ranked fixes for this error.

Is error code INVERTER BOARD FAIL on a Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU serious?

This error is rated critical severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Can I fix Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU error INVERTER BOARD FAIL myself?

Yes — the top-ranked community fix ("Replace the Inverter Board with Surge Protection Installation") is rated hard difficulty and takes about 150 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Label maker, Wire stripper.

How much does it cost to repair Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU error INVERTER BOARD FAIL?

DIY cost: $20-$30. Professional repair typically costs $400-$600. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU have?

The Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU has 8 other known error codes, including: CONDENSATE DRAIN BLOCK (Condensate Drain Blockage / Water Leak), E1 (Compressor High Pressure Protection), E2 (Indoor Coil Anti-Freeze Protection), E3 (Compressor Low Pressure Protection), E4 (Compressor Discharge Temperature Protection), and 3 more.

What other error codes does the Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU have?

The Lennox MPA012S4S Lennox Mini-Split Heat Pump System 12,000 BTU has 8 other known error codes:

CONDENSATE DRAIN BLOCK — Condensate Drain Blockage / Water Leak (2 fixes)
E1 — Compressor High Pressure Protection (2 fixes)
E2 — Indoor Coil Anti-Freeze Protection (2 fixes)
E3 — Compressor Low Pressure Protection (2 fixes)
E4 — Compressor Discharge Temperature Protection (2 fixes)
E5 — Compressor Overcurrent Protection (2 fixes)
E6 — Communication Error — Indoor/Outdoor (2 fixes)
E8 — Indoor Fan Motor Fault (2 fixes)

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