e1
Moderate
Rheem · HVAC Systems & Water Heaters
Sensor Failure (Water Heater)
Quick Answer
Error code E1 on your Rheem HVAC Systems & Water Heaters means: Sensor Failure (Water Heater). This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Locate the thermistor sensors on the tank and check their connectors
2
Measure thermistor resistance and compare to the manufacturer's chart for current water temperature
3
Inspect sensor wiring for corrosion or moisture damage
4
Replace the faulty sensor if resistance is out of specification
5
If multiple sensors fail simultaneously, check the control board for damage
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 heater thermistor sensor
Wire connectors
Control board (if sensor circuit failed)
Related Error Codes