E07 displayed and thermostat shows battery icon with a cross or low level (for battery‑assisted or wireless models).

Safety first: For wireless room units, there is no mains voltage inside the device, but keep away from children when handling batteries.

• Step 1 – Replace batteries: Open the battery compartment and replace all cells with new, high‑quality alkaline batteries of the specified type. Do not mix old and new batteries.
• Step 2 – Clean contacts: If there is white or green corrosion on the contacts, gently clean with a cotton swab lightly moistened with isopropyl alcohol. Allow to dry completely before inserting new batteries.
• Step 3 – Check polarity: Ensure batteries are inserted with correct +/− orientation as indicated in the compartment.
• Step 4 – Reset pairing: After battery replacement, some Atlantic wireless thermostats require re‑pairing with the receiver module. Follow the pairing procedure in the manual (usually pressing a link button on the receiver and then on the thermostat).
• Step 5 – Internal fault: If E07 persists immediately after installing known‑good batteries and the contacts are clean, the battery sensing circuit on the PCB may be faulty. In that case, replace the wireless room unit.