Hitachi Water Heater Error 3

⚡ Quick Answer: The Hitachi water heater error code 3 (Er03) indicates an abnormality in the 150L tank temperature sensor, which can lead to issues such as improper w... ⚠️ Difficulty Varies

What Does Error 3 Mean?

The Hitachi water heater error code 3 (Er03) indicates an abnormality in the 150L tank temperature sensor, which can lead to issues such as improper water temperature regulation and unusual clicking noises. The system may stop heating entirely if the sensor readings are faulty, requiring attention to ensure consistent hot water supply.

Common Symptoms:

  • Error code Er03 displayed on the unit/control
  • Possible incorrect water temperature or inability to properly regulate tank temperature
  • System may shut down or stop heating due to abnormal sensor reading

Possible Causes

  • Temperature sensor (150 L section) fault (medium)
  • Temperature sensor wiring issue (open circuit, short, connector problem) (medium)
  • Control board misinterpreting temperature sensor signal (low)

How to Fix Error 3

DIY Fix Power cycle and basic check

  1. Turn off the main breaker or power switch to the water heater.
  2. Wait at least 10 seconds and then restore power.
  3. Check whether the error code clears upon restart.

Technician Only Inspect and test temperature sensor and wiring

  1. Disconnect power to the unit.
  2. Access the 150 L tank temperature sensor location per service manual.
  3. Measure resistance of the temperature sensor and compare with manufacturer specs.
  4. Inspect wiring harness and connectors to the sensor for continuity and secure contact.
  5. Replace the temperature sensor or repair wiring as needed.

Parts needed: 150 L tank temperature sensor, Wiring harness/connectors

🛑 When to Call a Pro:
  • Error persists after power cycling
  • Sensor tests show out‑of‑range resistance or open circuit
  • Wiring appears damaged and beyond simple reconnection

Technical Specifications

wattage 4500W
component Heating Element
resistance 10-30 ohms
part_number HE-12345
voltage_rating 240V AC

Common Questions

What does 3 error mean on hitachi water heater?

Error 3 indicates a malfunction in the temperature sensor for the 150L tank, causing heating issues.

Can I fix hitachi water heater 3 error myself?

You can try power cycling the unit. If the error persists, further inspection is needed.

How much does it cost to fix 3 error?

Repair costs for the 3 error range from ¥5,000 to ¥20,000, depending on parts and labor.

When should I call a technician for 3?

Call a technician if the error remains after power cycling or if sensor tests show faulty readings.

Data last verified: 2026-07-01

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