Rheem Furnace Code 26: Line and neutral reversed
If you smell gas or a CO alarm sounds, leave the home and call the gas utility or 911 from outside.
Rheem furnace code 26 indicates line and neutral reversed. The (-)801T upflow/horizontal and (-)(-)80MSX manual lists 26 as “LINEAND NEUTRAL REVERSED”. Match the full model to this manual before requesting a diagnosis. Give the contractor the displayed signal, the furnace model, and the point in the heating cycle when it appeared.
Talk to a contractor about your Rheem furnace code 26
Call (877) 565-3062One call reaches a contractor registered for your ZIP; ask the fee and the arrival window.
HVAC Responder is an independent referral service and is not affiliated with or authorized by Rheem.
HVAC Responder Editorial Team · Reviewed 2026-11-01 · Facts quoted from manufacturer documentation
What the Rheem manual says
(-)801T upflow/horizontal and (-)(-)80MSX; 92-24161-144-09 · PDF page 39.
According to Rheem (-)801T installation instructions (92-24161-144-09):
LINEAND NEUTRAL REVERSED
Discuss your Rheem furnace code 26 with a contractor
Call (877) 565-3062One call reaches a contractor registered for your ZIP; ask the fee and the arrival window.
How to describe the 26 condition
The table identifies reversed line and neutral. Supply-polarity investigation is electrical work inside the installation, not a thermostat setting to change. Mention a recent electrical alteration only if one occurred, and ask the service provider to verify the wiring condition.
Code family and related symptoms
What happens when you call about your Rheem furnace code 26
- Your call routes to an independent local contractor registered for your ZIP code.
- Ask the fee and the arrival window.
- The decision to hire stays with you.
One call reaches a contractor registered for your ZIP; ask the fee and the arrival window.
Sources and review date
- Rheem (-)801T installation instructions (92-24161-144-09), PDF · Read 2026-11-01
- CPSC Carbon Monoxide Fact Sheet · Read 2026-11-01