Aprilaire HVAC Error Code E1

E1 indicates that the internal RH and temperature sensor is not sending a valid signal to the User Interface Assembly. The sensor circuit has either opened or shorted, meaning readings are unavailable. The control displays E1 to flag that humidity and temperature regulation cannot function correctly until the issue is resolved.

A simple power reset will not permanently clear E1 if the underlying sensor fault remains present. The code will return as soon as the control attempts to read the sensor again. The error will only clear once the connection is repaired or the faulty RH Sensor board is replaced.

If the issue is only a loose connector, there may be no parts cost, just a service call fee which typically ranges from $75 to $150 depending on your area. If the RH Sensor board (5460) needs replacement, parts and labor combined generally fall in the range of $100 to $250. Costs vary based on local labor rates and where the part is sourced.

A knowledgeable DIYer can attempt the first diagnostic step: turn off power to the unit, remove the User Interface Assembly, and inspect the connector between the sensor board and the control board. If the connector is simply loose, reseating it may clear the fault. If the sensor board itself has failed, replacing part 5460 requires basic disassembly skills but is generally within reach for experienced DIYers.

The E1 error means the Aprilaire humidity control cannot accurately measure or regulate humidity and temperature. The core HVAC system may continue to operate, but the humidity control will not function correctly with this fault active. Running the system without a functioning humidity sensor could result in uncontrolled indoor humidity levels, so addressing the fault promptly is recommended.