Smart thermostat loses Wi-Fi

Controls / thermostat

AirCompDX - Field Reference for Air Compressor Techs
All HVAC symptoms
1

Weak signal / 5 GHz-only network

low
CheckMost stats need 2.4 GHz.
FixEnable 2.4 GHz SSID; move router or add mesh node.
2

No C-wire (using power-stealing)

med
CheckBattery drains; drops offline hourly.
FixPull a C-wire or install fast-stat add-a-wire adapter.
Safety

Pull the disconnect and lock out before opening HVAC equipment. Discharge dual-run capacitors before handling. Refrigerant recovery and brazing require EPA 608 certification and proper PPE.