Hybrid Heater Codes

Rheem · ProTerra / Performance Platinum hybrid (Gen V, 240V)

Rheem ProTerra / Performance Platinum hybrid (Gen V, 240V) error code A103

Lower Heater Temp Sensor Failure

What it means

Lower tank temperature sensor malfunction. Heater disabled.

Source: Electric Residential Hybrid Water Heater Use & Care Manual With Installation Instructions for the Installer, AP23657 Rev 04, page 33

Also listed in: Electric Residential Hybrid Water Heater Use & Care Manual (earlier revision), AP23657 Rev 01, page 32

Also listed in: Electric Residential Hybrid Water Heater Use & Care Manual (earlier edition), AP21681, page 27

What Rheem says to do

These steps involve electrical testing or parts replacement. Rheem's manuals tell owners to leave that work to a qualified service technician.

1. Check connections of the wiring and sensors. 2. Get an Ohm reading on the thermistors (if multimeter is available) (See Ohm chart for correct readings based on ambient temperature). 3. Check on display by selecting Service-->Sensors-->If sensor shows - 40°F, the circuit is open. +250°F indicates the circuit has shorted. Note: To confirm reading, power down the unit and unplug the thermistor from the board. Check Ohm reading. (See ohms chart)

Last checked 2026-10-03.

Safety first

From the manufacturer's manual for this series.

The same code on other models

Codes mean different things on different heaters. Match the series to the model number on your rating label.

Other ProTerra / Performance Platinum hybrid (Gen V, 240V) codes