to replace the automatic air vent View visual findings from this job here - https://visionshare.xoi.io/?id=XA-90AE-1C123A619A594CCBA26982A51668D024 Arrived at 10 Sunnybtae Pl., Bronxville, NY as a courtesy call due to technician being there today and performed maintenance and homeowner has no hot water now check system hot water boiler Diagnosed it was off because the high limit aquastat was tripped. Further checks revealed manual. Reset aquastat set at 190 and boiler aquastat set at 190 recalibrate both aquastat and tested system upon system testing diagnosed. The automatic vent was defective replaced automatic air vent and purged air Out of system for heating zone and one domestic hot water zone for indirect tank, tested all systems, including domestic, hot water and left system working