On the covered Rheem tankless gas water heater, 24 means error: the remote control buttons were pressed for more than 20 seconds. First, release the buttons and operate the unit. Then: Rheem's pocket manual says to release the buttons and operate the unit, and that if code 24 appears again, to continue to remote control diagnostics. Rheem's steps when a code shows: turn on a hot water faucet and recheck the remote control display.
If the code stays, turn off the faucet and the water heater, unplug the water heater for about 30 seconds and plug it back in, follow the chart for your code, restart the water heater and recheck. If the code is still shown, turn off the faucet and the water heater, note the code and call for service. If a code is not in the chart, turn the water heater off immediately and call for service.
Try in this order
0 of 17 completedWhat to do first
ReversibleRelease the buttons and operate the unit.
Correct only the documented fault domain
ReversibleRheem's pocket manual says to release the buttons and operate the unit, and that if code 24 appears again, to continue to remote control diagnostics. Rheem's steps when a code shows: turn on a hot water faucet and recheck the remote control display. If the code stays, turn off the faucet and the water heater, unplug the water heater for about 30 seconds and plug it back in, follow the chart for your code, restart the water heater and recheck. If the code is still shown, turn off the faucet and the water heater, note the code and call for service. If a code is not in the chart, turn the water heater off immediately and call for service.
Disconnect the remote controller
ReversibleRheem's first check for code 24 is to unplug the remote control and try again; a stuck button on it shows as an operational switch fault.
Check the grounding
ReversibleMake sure the unit is properly grounded and is not on a 2-prong adapter; Rheem's manual lists it alongside code 24.
Check whether anyone is leaning on the remote
ReversibleCode 24 means the remote control's buttons stayed pressed for more than 20 seconds, so look for something resting on them, such as a child's hand or an object leaning against the remote.
Disconnect the remote to test
ReversibleRheem's first check is to unplug the remote control and try again. A stuck button on the remote reads as a switch fault, so if the code disappears with the remote disconnected the remote is the part to replace.
Look for moisture or damage on the remote
ReversibleWipe off any condensation, dust or cooking residue and check the cable for pinching, since a damp keypad can read as a held button.
Release the buttons
ReversibleCode 24 means that a button on the remote control has been pressed for more than twenty seconds. Take your fingers off the controller and wait a moment. Rheem's pocket manual says to release the buttons and operate the unit.
Check for a stuck key
ReversibleA key that is jammed by dirt, a cable pinch or a damaged membrane can look like a held button. Press each key gently and see whether any feel stuck or fail to spring back.
Look at the controller cable
ReversibleA cable that is pinched or has a damaged insulation can short two contacts, which the heater reads as a held button. Look along the cable for a crushed section and straighten it.
Run remote control diagnostics
ReversibleIf code 24 appears again, Rheem says to continue to the remote control diagnostics in the manual. These steps test each button and the cable, and they are a way of telling whether the controller or the heater is at fault.
Replace the controller if it is faulty
ReversibleA controller with a stuck key or a bad cable can be replaced without replacing the heater. Ask the technician to test it first, and quote the model number from the heater's label.
Record when the code appeared
ReversibleNote whether it appeared after someone used the controller, after cleaning near it or after a power cut. The timing helps decide if the controller is at fault.
Check for a wet or dirty controller
ReversibleMoisture or grease under the keys can make them stick. Wipe the controller with a dry cloth. Do not spray cleaner on it.
Look at the cable run
ReversibleA cable that has been pinched in a door, bent sharply or chewed can short. Follow the cable to the heater and straighten it.
Try disconnecting the controller if the manual allows
ReversibleRheem's diagnostics tell you how to test the controller on its own. Follow the manual's order and do not open the heater.
Replace the controller
ReversibleIf the controller is faulty, a replacement restores normal operation. Quote the heater's model number so that the right controller is supplied.
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Exact questions
Common questions about “Rheem tankless gas water heater code 24”
What does 24 mean on a Rheem tankless gas water heater?+
Error: the remote control buttons were pressed for more than 20 seconds.
Can a stuck button on the Rheem controller cause code 24?+
Yes, code 24 is an operational switch fault and a controller button that is held down reads as one. Disconnect the remote to test.
Does code 24 mean the water heater itself is faulty?+
Not usually. It points at the remote control, which is a separate, replaceable part, so a stuck button is far more likely than a failure in the heater.
Will the heater still make hot water with code 24 showing?+
Release the buttons and operate the unit as Rheem says; if hot water still does not run, follow the general code steps and call for service.
Is the heater faulty?+
Often the controller or its cable is at fault.
What does Rheem say to do?+
Release the buttons and operate the unit, then run the diagnostics if it repeats.
Can the controller be replaced alone?+
Yes, in most cases.
Why does code 24 appear without anyone pressing buttons?+
A stuck key or a shorted cable can look like a held button.
Can I clean the controller?+
Wipe it with a dry cloth.
Is the heater safe meanwhile?+
Yes, if it makes hot water normally.