Thermostat shows E15 and cannot complete firmware update via the Wiser app.

Safety first: Ensure devices remain powered and do not remove batteries during firmware operations.

• Stabilise connection: Move closer to the router/HubR to ensure strong signal. Avoid updating during known power interruptions.
• Retry update: Use the Wiser app to retry the firmware update. Follow any on-screen guidance from Drayton.
• Power-cycle devices: Reboot the Wiser HubR and thermostat, then attempt the update again.
• Factory reset if stuck: If the thermostat is stuck in a boot loop with E15, perform a factory reset as per Drayton instructions and then re-add it to the system.
• Replace if bricked: If the device cannot recover from E15 and will not pair or operate, it may be bricked. Replace the thermostat or HubR.