e5
Moderate
Rheem · HVAC Systems & Water Heaters
Sensor Failure (Tankless Water Heater)
Quick Answer
Error code E5 on your Rheem HVAC Systems & Water Heaters means: Sensor Failure (Tankless Water Heater). This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Access the tankless unit control board and locate the temperature sensors
2
Measure each sensor's resistance and compare to the manufacturer's specification chart
3
Check sensor connectors for corrosion or loose connections
4
Verify the correct sensor type is installed for the specific model
5
Replace any sensor that reads out of specification
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Water temperature sensor (inlet or outlet)
Sensor gasket
Wire connectors
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