Rheem 24
Rheem code 24: remote or operational switch
Short answer
On current Rheem and Ruud models, code 24 means remote control buttons were pressed for more than 20 seconds; release them and operate the unit. If it returns, the remote and its wiring are checked. On earlier models, code 24 is an operational switch malfunction, reset by pressing the MAX and MIN buttons on the circuit board, and otherwise fixed by replacing the board.
Code 24 is usually one of the easiest Rheem codes to clear, but its meaning depends on the age of your unit.
This page uses two Rheem sources: the current Rheem and Ruud tankless troubleshooting manual, and Rheem's error code list for earlier tankless models. Codes can differ between generations, so the meaning for each is shown where they differ. Rheem technical support: (800) 432-8373.
What it means by model generation
| Rheem generation | Meaning |
|---|---|
| Current models | Remote control buttons pressed for more than 20 seconds |
| Earlier models | Malfunction of the operational switch on the control board |
Current models
- Release all buttons on the remote control.
- Operate the unit normally.
- If code 24 returns, check the remote for a stuck button and inspect its wiring for loose or damaged connections.
- A faulty remote is replaced.
Earlier models
Rheem's remedy is to press the MAX button and then the MIN button on the control board to reset it. If that does not work, the board is replaced. This is technician work, since it means opening the unit.
Before you call
Have the model and serial number from the rating label ready, and note whether your unit is a condensing (high-efficiency) or non-condensing model. Tell the technician the exact code, when it appears and any recent work on the gas, water, venting or electrical supply. That often saves a second visit.
See every code on our Rheem error codes page.
Common questions
Why does my Rheem show code 24 after cleaning the remote?
A button may have been held or stuck. Release all buttons and check for a stuck one.
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Other Rheem codes
| Code | Meaning |
|---|---|
| 00 | Continuous combustion for more than one hour |
| 03 | Communication failure between units, remote or manifold controller |
| 05 | Improper combustion detected by the flame rod (warning) |
| 10 | Air supply or exhaust blockage (hard lockout) |
| 11 | Ignition failure |
| 12 | Flame failure |
| 13 | Poor combustion detected by the flame rod (indoor units) |
| 14 | Overheat safety tripped |
| 15 | Heat exchanger or hot water temperature too high (boiling safety) |
| 16 | Outlet water temperature above the set point (over temperature warning) |
| 21 | Air intake filter switch fault (earlier models) |
| 24 | Remote control buttons held too long, or operational switch fault |
| 29 | Condensate not draining (condensing models) or heat exchanger temperature too low |
| 31 | Inlet water temperature sensor (thermistor) fault |
| 32 | Heat exchanger thermistor fault |
| 33 | Outlet (outgoing water) thermistor fault |
| 34 | Ambient or combustion air temperature sensor fault |
| 35 | Improper thermistor connection |
| 51 | Gas valve fault: flame detected after shutdown (current) / gas inlet solenoid valve fault (earlier) |
| 52 | Modulating gas valve (PGFR) fault |
| 61 | Blower (combustion fan) motor fault |
| 65 | Water volume control valve fault |
| 66 | Water bypass valve fault |
| 71 | Gas inlet solenoid valve fault |
| 72 | Flame rod fault: flame sensed before ignition |
| 76 | Remote control communication fault |
| 79 | Blower (fan) motor current fault |
| 80 | Gas cut-off failure: flame detected after the unit turned off |
| 82 | Control board program chip fault (current) / gas type data failure (earlier) |
| 90 | Vent blockage detected before ignition |
| 92 | Neutralizer needs replacing soon (warning, condensing models) |
| 93 | Neutralizer must be replaced; unit will not operate (condensing models) |
| 1L | Lime (scale) buildup detected in the heat exchanger |
| 99 | Vent blockage detected after shutdown / blocked flue (hard lockout) |
| P1 | Not enough water flow to fire the burner (warning) |