Rheem · HB Duct Ready Series (touchscreen)
Rheem HB Duct Ready Series (touchscreen) error code A903
Controller Fault.
What it means
Controller Malfuntion. Heater disabled. [sic]
What Rheem says to do
Call Tech Support at 1-800-995-0982 (number as printed in the 2018 manual).
Last checked 2026-10-03.
Safety first
- CAUTION: For your safety DO NOT attempt repair of electrical wiring, thermostats, heating elements or other safety devices. Refer repairs to qualified service personnel. (p.27)
- WARNING: If the water heater has been subjected to fire, flood or physical damage, disconnect all power to water heater, and DO NOT operate the water heater again until it has been checked by a qualified service technician. (p.16)
From the manufacturer's manual for this series.
The same code on other models
Codes mean different things on different heaters. Match the series to the model number on your rating label.
Other HB Duct Ready Series (touchscreen) codes
- A004 (Compressor Shutdown: Discharge-Suction Trip.)
- T005 (Compressor Shutdown: Discharge Temp High.)
- A006 (Suction Temperature Too Low.)
- T007 (Compressor Shutdown: Comp.Feedback Failure)
- A007 (Compressor Shutdown: Comp.Feedback Failure.)
- A008 (Detected Dry Fire Condition.)
- T009 (Compressor wiring may be faulty.)
- A101 (Suction Temperature Sensor Failure.)
- A102 (Ambient Temperature Sensor Failure.)
- A103 (Lower Heater Temp Sensor Failure.)
- A104 (Upper Heater Temp Sensor Failure.)
- A105 (Evaporator Temp Sensor Failure.)
- A106 (Discharge Temp Sensor Failure.)
- A107 (Water Detected on Floor: Check for Leaks.)
- A108 (Condensate Blocked: Unclog Line.)
- A125 (Lower Element Error or Relay Stuck Closed.)
- A126 (Upper Element Error or Relay Stuck Closed.)
- A127 (Element Wire Routing Error .)
- A128 (Lower Element Relay Failure to Close Error.)
- A129 (Upper Element Relay Failure to Close Error.)
- A130 (Unit Off/Air Temp Freezing: Enable Unit.)
- T131 (Clean Filter Reminder)
- T132 (Water Heater difficulty satisfying demand.)
- A200 (High Water Temp! [ECO].)
- T300 (Water Leak Sensor Not Installed.)
- A900 (Controller Fault.)
- T901 (Controller Fault.)
- A902 (Controller Fault.)
- A904 (Controller Fault.)
- A905 (Controller Fault.)