Takagi Reset

How to Reset a Takagi Tankless Water Heater

Soft reset, hard reset on Takagi tankless and T-T commercial cascade. When to use each.

Updated May 2026 · Takagi Water Heaters

"Reset the unit" is the first instruction Takagi support gives for most issues. Three reset levels.

Level 1: error code reset

For any displayed error code, press the On/Off button on the controller for 3 seconds. The unit attempts to restart.

Level 2: power cycle

  1. Turn off the unit at the controller
  2. Turn off the breaker
  3. Wait 30 seconds
  4. Restore power and turn the unit back on

Level 3: service menu

Requires installer password. Don't attempt without installer guidance.

T-T cascade individual unit reset

For T-T cascade installs:

  1. Isolate the target unit via the cascade controller
  2. Reset that individual unit's controller
  3. Bring the unit back into the cascade
  4. Verify cascade rotation works correctly

When reset doesn't fix things

Three resets with immediate re-throw = real fault. Stop cycling and work through the specific code's diagnostic walkthrough.

Bottom line

Start with Level 1. For cascade, isolate individual units before resetting the whole array.