If your YeloDeer thermostat displays E1 or E2, it’s a built-in safety feature alerting you to a sensor issue. Understanding these codes can help you (or your electrician) fix the problem quickly.
What Does E1 Mean? (Internal Sensor)
E1 indicates a failure with the Internal Room Sensor. This sensor is built into the thermostat unit to measure air temperature. If E1 persists after a restart, the internal component may be damaged. Please contact our support team for a replacement.
What Does E2 Mean? (External Floor Sensor)
E2 is much more common and refers to the External Floor Sensor installed under your flooring. An E2 code doesn't always mean the thermostat is broken; usually, it’s a connection or compatibility issue.
Common Causes of E2:
Loose Wiring: The wires may have slipped out of the terminal.
Insulation Clamping: The terminal screw is clamping down on the plastic insulation rather than the copper conductor.
Mismatched Settings: You have a 10K sensor but the thermostat is set to 15K.
Physical Damage: The sensor wire was pinched or cut during floor installation.
How to Test with a Multimeter
A multimeter is the best tool for diagnosing the system. Always turn off the power at the breaker before testing.
1. Testing the Floor Sensor
Set your multimeter to Ohms (Ω) and measure across the two sensor wires:
Reading near 0Ω: Indicates a short circuit (crushed wire).
OL or Infinite: Indicates an open circuit (broken or disconnected wire).
Expected Range: Should show a steady resistance (e.g., around 10k-15k ohms depending on temperature).
2. Testing the Heating Cable
Measure the resistance between the two power conductors of the heating cable. Compare this reading to the specification table in your manual. A reading far outside the range suggests a damaged heating cable.
Why Proper Wire Stripping is Critical
When inserting wires into the thermostat terminals, ensure the insulation is stripped back cleanly. If the terminal clamps onto the plastic jacket, it creates a "dead" connection, leading to an E2 error or, even worse, excessive heat at the terminal for power wires.