No hot water at any fixture; unit does not attempt to start (no fan or ignition sound)

Safety first: Do not open electrical panels unless you are comfortable working around electricity. Turn OFF the breaker before touching internal wiring.

Steps to check:

• Verify power source: Check the breaker feeding the Rinnai water heater and reset if tripped. Test the outlet (if corded) with another device.
• Check power switch: Some models have an external or internal power switch; ensure it is ON.
• Inspect power terminal: With power OFF, remove the front cover and verify wires are secure at the power terminal block.
• Controller display: If the remote controller is blank, power is likely missing or the control board has failed.

When to call a professional: If power is present at the outlet but the unit remains dead, a technician should test and possibly replace the main control board.