Lock key Controller locked (key symbol)

What the display is showing

While the controller is locked, the display alternates between the key/lock symbol and the set temperature (on RX/CX a key lights up on the controller). The set temperature cannot be changed until it is unlocked. Outdoor RX/CX units lock the controller by themselves after 30 minutes without use. The symbol itself did not come through the text export of the manual.

Applies to: Rinnai SENSEI tankless (RU, RUR, RSC, CU) and SENSEI RX/CX (RX, RXP, CX, CXP)

What to do

1. To lock press and hold Priority, then press Up as well until a beep sounds (about 5 seconds), and let go of both together.
2. To unlock repeat the same steps.

Settings for these units

RSC supply connection sizes · SENSEI

The PRV and its adapter come in the box; PRV must be rated 150 psi and at least the heater Btu/h.

Condensate drain line must stay at least 1/2 in. over its whole length.

RSC water quality limits · SENSEI

Damage from water above these limits is not covered by warranty.

Hard water should be treated; use the Service Soon (SS) reminder (parameter 03) for flushing intervals.

• RSC clearances to combustibles · SENSEI
• RSC temperature settings available · SENSEI
• RX supply connection sizes · SENSEI RX/CX
• RX water quality limits · SENSEI RX/CX
• RX water treatment and flushing by hardness · SENSEI RX/CX
• RX clearances to combustibles · SENSEI RX/CX

Models that show this code

30 models in SENSEI RX/CX, SENSEI

Other codes on the same units

• In Use fast flash In Use light rapid flash
• In Use slow flash In Use light slow flash
• In Use solid In Use light steady
• LC Scale build-up in heat exchanger (LC, LC0–LC9, 00)
• LPG Initial setting: propane (LPG)
• Mute Controller key beeps on/off
• Out Initial setting: outdoor installation
• Parameter mode Parameter settings menu