Thermostat or wiring centre makes a loud pop and stops working after a lightning storm or power surge.

Safety first: Immediately isolate power. Do not attempt to reuse any device that has suffered surge damage without inspection.

Steps to diagnose and fix:

• 1. Visual inspection: Look for burnt components, cracked ICs, or blown surge protectors inside the thermostat or wiring centre.
• 2. Test other devices: Check if other electronic devices on the same circuit are affected, indicating a broader surge event.
• 3. Replace damaged units: Surge-damaged PCBs are not economically repairable. Replace the thermostat, wiring centre, and any affected sensors or actuators.
• 4. Add surge protection: Install appropriate surge protection devices on the mains supply and, if recommended, on long sensor or bus cable runs.
• 5. Recommission system: After replacement, reconfigure all thermostats and verify correct operation of each zone.

When to call a professional: Surge assessment and protection design should be handled by an electrician or controls specialist.