Rheem Tankless Water Heater Error Code 17: Water Leak Detected (Meaning, Causes, Fixes)

What the code means

Rheem's High and Super High Efficiency Tankless Troubleshooting Manual (AP21822) lists 17 as "Water leak detected." It explains that the code is displayed only when the WiFi controller is used on the water heater: if the water leak sensor detects a leak inside the unit, 17 shows on the built-in controller or the remote controller, and the water heater may have water leaking from somewhere. The diagnostic check items are the heat exchanger and the water valve. Rheem adds that the sensor can also be triggered by causes that aren't internal components, so check whether condensation is building up in the cabinet or entering through the intake venting. The same manual lists two related warning codes: 48 means leak detection has been disabled through the WiFi app (Rheem allows disabling code 17 for 24 hours, after which 48 is shown), and 49 means the leak sensor is not installed on a unit using the WiFi controller. Rheem's wiring diagrams show the water leak sensor as a WiFi-model part. This page covers Rheem gas tankless models; other Rheem water heaters may use different code numbers.

Likely causes

• A leak from the water valve inside the unit (one of Rheem's two diagnostic check items)
• A leak from the outside piping of the heat exchanger (Rheem's other check item)
• Condensation building up inside the cabinet, which Rheem says can trigger the sensor without any component leaking
• Rain or condensation entering through the intake venting
• An outside source of water reaching the sensor, such as a dripping fitting, valve or pipe above or beside the heater

Safe DIY checks

1. Turn off all hot water faucets, then turn off the water heater with its power button.
2. Look under and around the heater for water on the floor or in the drain pan, and check the gas, water and relief valve fittings outside the cabinet for drips. Fix any outside source first.
3. Look at the intake vent and the termination outside. If rain or condensation is getting into the intake, the vent installation needs to be checked by the installer.
4. Only a qualified person should remove the front cover; Rheem's warning is to make sure power is off first. With the cover off and water flowing, Rheem's check is to look for a leak from the water valve and from the outside pipe of the heat exchanger.
5. If there's no leak from either part, Rheem says to dry off the leak sensor and look for external sources of the leak.
6. Clear the code the way the manual says: turn the heater off, wait about 5 minutes, turn it back on and run a hot faucet. If the code remains, unplug the heater for 30 seconds, plug it back in and try again.
7. Rheem's WiFi app can disable code 17 for 24 hours, after which the unit shows warning 48. Use that only to get hot water while you arrange a repair, not as a fix.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• 10 Rheem Tankless Water Heater 10
• 12 Rheem Tankless Water Heater 12
• 13 Rheem Tankless Water Heater 13
• 14 Rheem Tankless Water Heater 14
• 29 Rheem Tankless Water Heater 29

All Rheem codes →

Sources

1. Rheem High and Super High Efficiency Tankless Troubleshooting Manual AP21822, p.62 (17 Error Code: Water leak detected, WiFi models only; heat exchanger and water valve checks; condensation and intake-vent note; warning codes 48 and 49)
2. Rheem Tankless Easy Installation Guide (clearing alarms: 5-minute restart, then 30-second unplug)
3. Rheem Eagle Tankless Use and Care Manual AP22009 (wiring diagram showing the WiFi-model water leak sensor; error code reset steps)