Tag: water-heater

All the articles with the tag "water-heater".

• Bosch E3 Error Code - Causes & Fix

  31 May, 2026

  E3 on Bosch tankless heaters signals a flue gas temperature sensor fault or overheating. Check sensor wiring, test the sensor, or descale.

• Bosch E1 Error Code - Causes & Fix

  31 May, 2026

  E1 means the hot water sensor detected over-temperature (above 185°F). Most often caused by scale buildup or a faulty sensor.

• A.O. Smith E21 Error Code - Causes & Fix

  31 May, 2026

  E21 means a shorted thermistor (TH-1 or T-Out). Most often the sensor itself has failed. Check wiring, then replace the thermistor.

• A.O. Smith Tankless E20 Error - Causes & Fix

  31 May, 2026

  E20 means the inlet thermistor is shorted. The fix is to replace the inlet temperature sensor or check its wiring and connections.

• A.O. Smith E10 Error Code - Causes & Fix

  31 May, 2026

  E10 means the inlet temperature sensor is open. Check the thermistor connection first, then replace the sensor if the code returns.

• A.O. Smith Tankless E06 Error - Causes & Fix

  31 May, 2026

  E06 on an A.O. Smith tankless heater means water temperature is too high. Run a hot tap for 5 minutes to clear the fault or check sensors.

• A.O. Smith Tankless E04 Error - Causes & Fix

  31 May, 2026

  E04 on an A.O. Smith electric tankless water heater means moisture or a leak is detected inside. Turn off power and water, then call support.

• A.O. Smith Tankless E02 Error - Causes & Fix

  31 May, 2026

  E02 means over-temperature: heated water exceeded the limit. Most often caused by low flow or a failing thermistor. Here's how to fix it.

• Rinnai LC Error Code - Causes & Fix

  31 May, 2026

  LC code means scale buildup in the heat exchanger. Flush the unit with descaling solution to clear the code and restore full operation.

• Navien E782 Error Code - Causes & Fix

  31 May, 2026

  E782 means abnormal main panel communication. Usually caused by a failed PCB or loose connector. Check wiring first, replace board if needed.

• Navien E777 Error Code - Causes & Fix

  31 May, 2026

  E777 means abnormal LWCO operation on Navien combi units. Most often it's a loose LWCO wire or low water level on the heating side.

• Navien E740 Error Code - Causes & Fix

  31 May, 2026

  E740 means outdoor temperature sensor failure. Check sensor wiring and outdoor reset configuration, or replace the sensor if damaged.

• Navien E615 Error Code - Causes & Fix

  31 May, 2026

  E615 signals an abnormal control-board or input/memory fault. Most likely fix is to power-cycle the unit and replace the PCB if it returns.

• Navien E594 Error Code - Causes & Fix

  31 May, 2026

  E594 means abnormal EEPROM operation on your Navien tankless heater. The main control board has failed or corrupted memory. Replace the PCB.

• Navien E030 Error Code - Causes & Fix

  31 May, 2026

  E030 means exhaust overheat on your Navien tankless water heater. Most often caused by blocked venting or a clogged inlet filter.

• Navien E110 Error Code - Causes & Fix

  30 May, 2026

  E110 means abnormal air pressure or blocked airflow. Most common fix: clean the internal air filter and check vents for blockages.

• Navien E009 Error Code - Causes & Fix

  30 May, 2026

  E009 means abnormal fan motor speed on your Navien tankless. Most often caused by blocked intake, dirty filter, or failed blower motor.

• Navien Alarm 438 - Causes & Fix

  30 May, 2026

  Alarm 438 means a recirculation system fault. Most often a closed valve, clogged filter, or failed circulation pump stops flow in the loop.

• Noritz F76 Error Code - Causes & Fix

  30 May, 2026

  F76 means communication lost between paired Noritz units. Most likely fix: power down, reseat the quick-connect cord, and restart.

• Navien Alarm 415 - Causes & Fix

  30 May, 2026

  Alarm 415 means the flow sensor isn't detecting water movement. Most often caused by debris or scale in the sensor. Clear the inlet filter first.

• Navien E515 Error Code - Causes & Fix

  30 May, 2026

  E515 signals an abnormal PCB condition on your Navien tankless. Most common fix is reseating connectors or replacing the main control board.

• Navien E038 Error Code - Causes & Fix

  30 May, 2026

  E038 means the flow sensor isn't spinning. Open and close the pressure relief valve to free debris, or replace the sensor if stuck.

• Navien E029 Error Code - Causes & Fix

  30 May, 2026

  E029 means air pressure sensor abnormality. Most common fix: check wiring, clear vent blockages, or replace the air pressure sensor.

• Navien E021 Error Code - Causes & Fix

  30 May, 2026

  E021 means the cold water inlet thermistor has an open circuit. Most common fix: replace the failed sensor or repair its wiring.