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Navien Tankless Water Heater: Cancel the cascade setting

Updated · by Aurora Star Tech Inc.

Cancel the cascade setting on a Navien tankless water heater: Undoes the main/sub pairing from the main heater.

Homeowner with a tankless water heater problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: NPN-160U/180U/199U, NPN-120E/160E/180E/199E

How to fix cancel the cascade setting: step by step

  1. On the main unit hold Diagnostic + Reset for 5 seconds.
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

If the unit shows an error code, look it up: Navien Tankless Water Heater codes

Models

NPN-120ENPN-160ENPN-160UNPN-180ENPN-180UNPN-199ENPN-199U

Source: Navien NPN-U/NPN-E Installation Manual, 5.2.1 Configuring the Communication Settings, p.58. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

© 2026 Aurora Star Tech Inc. All rights reserved. This page may not be copied, republished or used to train other systems without written permission.

Emergency HVAC Service

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