Thermostat shows E08 and battery icon flashes or device powers off intermittently

Safety first: Battery replacement is safe for users. If your thermostat is mains powered via a transformer, isolate power before inspecting wiring.

• Replace batteries: Use fresh, high-quality alkaline batteries of the specified type. Avoid mixing old and new cells or different brands.
• Clean contacts: Inspect the battery compartment for corrosion. Clean light corrosion with a cotton bud and isopropyl alcohol. If heavily corroded, the thermostat may need replacement.
• Check orientation: Ensure batteries are inserted with correct polarity as marked.
• For mains-powered units: Verify the correct power adapter is used and firmly connected. If using a 24V transformer, ensure its output is stable and correctly wired.
• If E08 persists: The internal power regulation circuit may be faulty. Replace the thermostat.