Thermostat displays 'LOW BAT', battery icon, or flashes a battery symbol; heating may become intermittent or RF range reduced.

Safety first: No mains work is required; just handle batteries safely.

Steps to check:

• Replace batteries: Open the battery compartment on the Salus thermostat (e.g. RT510RF, RT310i, RT305). Fit new, high-quality alkaline AA or AAA cells as specified. Do not mix old and new batteries.
• Inspect contacts: Check the metal contacts for corrosion or rust. Clean gently with a dry cloth or a pencil eraser. Do not use liquids inside the thermostat.
• Check orientation: Ensure batteries are inserted with correct polarity (+ and −) as marked.
• Test operation: After replacement, confirm that the low battery icon disappears and that the thermostat can communicate with the receiver.

Resolution: If low battery warnings persist with new batteries and clean contacts, the battery sensing circuit may be faulty. Replace the thermostat head.