What is an E2 fault in heater? - Water Heaters

An E2 code is often an indicator of an electrical problem inside the water heater. The most common problem is with the inlet water temperature sensor. Often a reset will fix the problem. To achieve the reset unplug the unit. Open the unit being careful of fragile electrical wires. Next remove the computer board and then disconnect each plug in wire and reseat them one at a time. Reassemble the unit and plug it in. It should be in working condition, without the E2 code.

Ahhhhh..try contacting the Avinditi tankless water heater people, or see if there's water getting to the unit if not it'll show and no water code good luck

If you read the manual, this is the code that the cooker has overheated ... let it cool for 15mins or so and switch it back on, it'll be fine!

E2 is a cold water inlet temp sensor. Has your unit experienced any freezing conditions? If it senses below 36 degrees or above 90 degrees it will show this error.

If its normal temp, and you still get this error...check your sensor. Its an 8(kohm) sensor. Make sure its not open. If it reads ok and your temp is not an issue, then you probably have a bad control board

E2 is a cold water inlet temp sensor. Has your unit experienced any freezing conditions? If it senses below 36 degrees or above 90 degrees it will show this error.

If its normal temp, and you still get this error...check your sensor. Its an 8(kohm) sensor. Make sure its not open. If it reads ok and your temp is not an issue, then you probably have a bad control board

e2 is not shown among common error codes:
Error e2 might be: Brownout condition or too low of voltage to thermostat. Double check wiring and check for 24 vac between R and C. E2 will clear 15 sec after proper voltage is restored.

Before calling service technician, open following link for Rheem troubleshoot resources including Rheem chat and typical generic manuals and common error codes:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

Model number and serial number are required for Rheem contact, and then they tell you what error code means without saying how to fix it, and then tell you to call service technician.

Tankless water heater manuals each say to have qualified technician perform yearly service. Most causes for common error codes are covered by yearly service.

Yearly service is fairly standard in the HVAC and water heater industry with advancement of high-tech 'energy' saving appliances. Of course all costs are energy, and the service call probably costs more that the 'energy' saved by energy-saving appliance. But with high tech stuff like tankless, it is good to have a reliable service guy who knows your machine.
http://waterheatertimer.org/images/Tankless-wiring-1200.jpg

Before calling service technician, open following link for Bosch troubleshooting resources, including error codes, manual, Bosch contact info, and service bulletins.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Error codes are starting point for troubleshoot.
e2 is cold water temperature sensor fault.
Bosch error code says: 1) Check connector on wires coming from top of water valve for a secure connection.
2) Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions Any damage due to freezing conditions is not covered under warranty.

Another contributing cause can be temperature thermostat set very high and tankless sensor is going bad, and very cold incoming water, or combination of factors above.

Also read manual for advisories and required maintenance. Some units require water filter be cleaned monthly.

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You posted under Rheem water heater
E2 sounds like a Bosch error code: E2: Cold water temperature sensor fault.
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ESTechSupport/Troubleshooting/tabid/1295/Default.aspx

it sounds like your flu pipe may be clogged,, they just snap together or have little screws holding them together,, take the sections apart and make sure nothing is is the line reinstall and try it out