Rheem R96VA0702317MSA Error Code 26: Line and Neutral Reversed or Poor Ground
What Does Code 26 Mean?
A code 26 on the Rheem R96VA0702317MSA is a critical fault indicating the line voltage and neutral wires feeding the furnace are interchanged, or the furnace control board cannot properly sense its ground connection. Correct electrical polarity is essential for the flame sensing circuit, which uses the electrical difference between the hot conductor and the grounded system to detect burner flames. With reversed polarity or an absent ground, flame detection is compromised, so the IFC refuses to allow any operation — no heating, cooling, or fan-only modes will function.
This condition typically results from incorrect wiring at the furnace disconnect switch, junction box, or circuit breaker panel — most commonly when the hot (line) and neutral wires were installed in the wrong terminals. It can also occur if the furnace was incorrectly wired during original installation or after a recent repair. A missing or inadequate ground connection can trigger the same code because the IFC cannot complete its reference path for flame detection.
Because this involves 115-volt AC line wiring, it must be repaired by a qualified electrician or HVAC technician. The technician should turn off the circuit breaker, verify the wiring at the furnace disconnect and breaker panel, correct any reversed conductors, and verify the ground connection is solid before restoring power.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a qualified electrician or HVAC technician to check and correct the 115-volt wiring polarity at the furnace, disconnect switch, and circuit breaker panel — do not work on line voltage wiring yourself
- The technician should also verify the furnace ground connection is intact and properly bonded, as a poor ground can trigger code 26 independently of polarity
✓ Verified against manufacturer service manual — March 2026