Oso water heater shows E15; unit may not respond to Wi‑Fi or remote app control (on connected models).

Safety first: Isolate power before unplugging or replacing any communication modules.

• Power cycle: Turn off power for a few minutes, then restore and see if communication resumes.
• Check module connections: Remove the cover and verify that the communication module is firmly seated in its slot and that any data cables are fully inserted.
• Relocate router/antenna: For Wi‑Fi issues, ensure the router is within range and not heavily shielded by metal structures.
• Update firmware: If Oso provides firmware updates, ensure both the main PCB and module are on compatible versions.
• Replace module: If E15 persists and local control works fine, replace the Oso communication/Wi‑Fi module.