AZ ROC R-4R Boilers (Residential) Practice Questions - Arizona ROC R-4R Boilers (Residential) Examination Exam

On the boiler supply pipe where water is at its highest temperature and lowest static pressure relative to the pump. On the return main pipe right before the water enters the boiler bottom drain connection. At the furthest terminal baseboard heater unit at the highest floor level. On the cold water makeup feed line immediately upstream of the pressure reducing valve.