Upon arrival spoke with customer. Customer recently had thermostat replaced. All thermostat were upgraded to google nest 4th gen. After master bedroom system was located. Had thermostat call for heat. Hydro lines are getting hot but system would not engage to active blower motor. Humming noise could be heard @ general relay. Check general relay and all fan relays. When terminal block was bypassed to run fan. Fan would engage. Thermostat setting was not allowing system to operate properly. Needed to reconfigure 4th gen. Google nest thermostat to active fan blower for older version of Unico air handler. Once thermostat was reconfigured. System began to operate normally. Took temperature rise/ temperature split @ master bedroom outlet. System is operating normally @ this time. Recommending to customer to schedule heating maintenance. View visual findings from this job here - https://visionshare.xoi.io/?id=XA-A243-477CDB48F3C446CAAFF894D43E6C9EA9