Question 159Steam Plants - Assistant Engineer

The correct answer is C) back to the suction side of the service pump. When preparing to light off a cold boiler with a return flow fuel oil system, the recirculating valve directs the flow of oil back to the suction side of the service pump. This allows the oil to be recirculated and further warmed up before being delivered to the fuel oil heater and the boiler. This ensures the proper viscosity of the fuel oil for efficient combustion. The other options are incorrect because: A) directly feeding the fuel oil heater inlet would not allow for proper warm-up of the oil, B) recirculating to the fuel oil settler would not provide the necessary warm-up, and D) directing the oil to the deep tanks would not serve the purpose of preparing the boiler for lighting off.