Display shows “Err 7” and unit does not keep correct time or loses settings

Safety: Disconnect the power supply before servicing electrical components.

• Check transformer output: Measure the output of the Autotrol plug-in transformer (typically 24 VAC). If voltage is low or absent, replace the 24 VAC transformer.
• Inspect power connections: Ensure the low-voltage plug is fully inserted into the control and that there are no damaged wires or corroded terminals.
• Backup battery/capacitor: Some Autotrol controls use an internal battery or super-capacitor to maintain time and settings. If the unit loses time whenever power is interrupted, the backup component may have failed. Replace the control board (backup is usually not field-serviceable separately).
• Surge protection: If there is evidence of surge damage, install a surge protector and replace the electronic control board.
• Reprogram: After repairs, set the correct time, hardness, and regeneration parameters and monitor for several days to ensure settings are retained.