Reset & cancel: Tankless Water Heater tips

Short, practical technician tips on reset & cancel for tankless water heater. Check each one against the manual for your exact model before acting.

Clear an error code with the ON/OFF key

Bosch · Greentherm T9800 SE 160/199 and T9900 SE 160/199 tankless water heaters

Holding ON/OFF for over 3 seconds clears an error code from the display; the appliance then runs its start-up sequence. If the error returns, call a licensed professional.

1. Touch and hold the ON/OFF key for more than 3 seconds
2. Wait for the start-up sequence

Cancel the cascade setting

Navien · NPN-160U/180U/199U, NPN-120E/160E/180E/199E

Undoes the main/sub pairing from the main heater.

1. On the main unit hold Diagnostic + Reset for 5 seconds.

Factory reset the panel and main controller

Navien · Navien NPE-A2 (built-in recirculation) and NPE-S2 condensing tankless water heaters: NPE-150S2, NPE-180A2/S2, NPE-210A2/S2, NPE-240A2/S2

Resets the panel and main controller parameters from the installer menu.

1. Hold Menu and Back together for 3 seconds.
2. Open 1. Installer Menu (password 1234).
3. Choose 6. Factory Reset.

Remove a cascade (Cascade System Removal)

Navien · NPE-A2, NPE-S2

Cascade removal is under the Cascade Status and Set menu of the hidden service menu.

1. Hold Menu and Back together for 3 seconds.
2. Open 2. Cascade Status and Set.
3. Choose 4. Cascade System Removal.

Reset one parameter to its default

Navien · Navien NPE-A2 (built-in recirculation) and NPE-S2 condensing tankless water heaters: NPE-150S2, NPE-180A2/S2, NPE-210A2/S2, NPE-240A2/S2

Returns a single installer parameter to its factory value without touching the others.

1. Open the parameter in edit mode (Menu + Back 3 s > 1. Installer Menu > 2. Parameter Settings).
2. Hold Back for 5 seconds while editing.

Reset the panel settings to defaults (Default Settings)

Noritz · Noritz EZ111/EZ98/EZ71 and NRCR111/NRCR92

Default Settings resets everything in Settings except Screen Lock.

1. Open Settings and choose Default Settings.
2. Hold OK for about 5 seconds.

Code 52 / 17 reset sequence on temperature controller

Rinnai · Code 52 and code 17 on SENSEI and Non-SENSEI series

Button sequence used to clear code 52 (and code 17) from the temperature controller. Disconnect power and gas before starting the work that leads to the reset.

1. Start with the controller off (blank display).
2. Press button B for 1 second until the display shows "t".
3. Press button B for 1 second until the display shows "F".
4. Press button B for 1 second until the display shows "S".
5. Press button B for 1 second until the display shows "E". Only do this step if code 17 or 52 is showing.
6. Press buttons A and B together for 10 seconds until the display shows "ECL". Reset is complete.

Controller reset sequence after venturi cleaning (code 17)

Rinnai · SENSEI Series, codes 17 and 52

Run this sequence after the venturi is cleaned and reinstalled to return the water heater to normal operation.

1. Start with the temperature controller off (blank display).
2. Press button B for 1 second until the display shows "t".
3. Press button B for 1 second until the display shows "F".
4. Press button B for 1 second until the display shows "S".
5. If code 17 or 52 is occurring, press button B for 1 second until the display shows "E".
6. Press buttons A and B together for 10 seconds. The display shows "ECL" when the reset is complete.

Reset after cleaning the venturi or replacing the gas valve (codes 17 / 52)

Rinnai · Rinnai SENSEI and SENSEI RX/CX tankless

Step through the reset screens with button B on the PC board, then finish with A and B together.

1. With the controller blank, press B for 1 second at a time to advance: SENSEI shows t, F, S, E; RX/CX shows dES, t, AdJ, F, A, E.
2. E appears only while code 17 or 52 is active.
3. Finish by pressing A and B together for 10 seconds until ECL shows.

Reset procedure for code 52 (and code 17)

Rinnai · Code 52 and code 17

Used to clear code 52, and code 17 when it is occurring. Start with the controller off (blank display). Use buttons on the PC board or temperature controller as shown in the manual. Shut off gas and water before service.

1. With the controller off (blank), press button B for 1 second. Display shows "t".
2. Press button B for 1 second. Display shows "F".
3. Press button B for 1 second. Display shows "S".
4. Press button B for 1 second. Display shows "E" (only needed if code 17 or 52 is occurring).
5. Press buttons A and B together for 10 seconds. Display shows "ECL" when reset is complete.

Reset the Service Soon (SS) reminder

Rinnai · RU199i/e, RU180i/e, RU160i/e, RU130i/e

Clears the Service Soon reminder on the residential, pump and commercial models.

1. Press On/Off 5 times.