Ruud R96T fault 58: open water-sensor circuit

What Does Error 58 Mean?

On the documented Ruud R96T, fault 58 means the water-sensor circuit is open. Depending on the installed configuration, that path can include a water sensor or a required jumper plus its wiring and control input. It is not the same as the combustion pressure-switch codes and does not prove water is present. Applies to: R96T two-stage communicating condensing furnaces This definition is limited to the R96T manual cited here. Rheem and Ruud share some platforms, but model suffix, control generation, optional sensor configuration, and the exact code table still govern the diagnosis. Owner-safe checks: Keep panels closed, photograph fault 58 and the rating plate, and observe only external water or recent drain work from a safe position. Qualified technician: Configuration verification, sensor and jumper access, continuity tests, condensate diagnosis, wiring repair, and control-input checks require qualified furnace service.