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Goodman · Furnace

EEA Reversed line polarity or grounding error

High severity Goodman/Amana GM9S96/AM9S96Goodman/Amana GM9S80/AM9S80Goodman/Amana GM9C96/AM9C96

What the control is telling you

The control detected that the 115 VAC hot and neutral are reversed, or the unit ground is poor. The furnace will not operate.

Applies to: Goodman/Amana/GMC gas furnaces, 9-speed ECM, 7-segment control. Two-stage 96%: AC9C96, AM9C96, GC9C96, GM9C96. Single stage 80%: VC9S80, VM9S80, AC9S80, AM9S80, GC9S80, GM9S80. Single stage 92/96%: VC9S96, VM9S96, AC9S96, AM9S96, AM9S92, GC9S96, GM9S96, GM9S92

Likely causes

  • Hot and neutral swapped at the furnace or panel
  • Poor or missing ground wire
  • Transformer primary/secondary out of phase

Test and repair steps

  1. Warning: line voltage present - use care when measuring.
  2. Check that the black (hot) and white (neutral) supply wires land on the correct terminals; correct the polarity.
  3. Confirm there is a ground wire from the furnace j-box right back to the panel. Gas pipe or conduit does not count as ground.
  4. Power off and measure resistance from the neutral (white) connection to the burner nearest the flame sensor - it should be very low (the manuals give less than 2 ohms and also 10 ohms or less).
  5. If an unmarked transformer was replaced, check phasing: about 96 VAC between the connected primary/secondary leads means in phase, about 144 VAC means out of phase - reverse the low voltage leads.

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Source: Goodman RS6612022r1 (GM9S92/GM9S96/GC9S96 service), 1 Stage Troubleshooting Codes, p.29-30; Goodman RS6621008r2 (GM9S80 service), p.32-33; Goodman RS6612020r1 (GM9C96 service), 2 Stage Troubleshooting Codes, p.35-36; Servicing - polarity and phasing p.15, Checking Integrated Ignition Control Boards p.25 (RS6612022r1). Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.