Just resolved a defrost cycle issue on a Lennox heat pump system in Aubrey. Diagnosed failed defrost control board and faulty temperature sensor causing incomplete defrost cycles. Replaced the original Y7761 control board with updated model and installed new 10K outdoor coil temperature sensor. System now properly entering defrost cycle at 31°F with correct timing sequence. Heat pump operating at full efficiency. Available for heat pump diagnostics and repairs throughout the Denton County area. Licensed and insured professional.