What occurs to the flow rate at the nozzle when the temperature of the fuel decreases?

When the temperature of the fuel decreases, the flow rate at the nozzle can actually decrease rather than increase. This is because cooler fuel is denser than warmer fuel. As the density of the fuel increases, its viscosity can also change, making it more resistant to flow through the nozzle.

Fuel oil systems are designed to operate optimally within certain temperature ranges, and when the temperature drops, the physical properties of the oil can lead to a reduction in the flow rate. This reduction can also be influenced by how the fuel is heated or conditioned before reaching the nozzle. As such, it's critical for technicians to monitor fuel temperature and adjust heating systems accordingly to ensure optimal flow rates and efficient combustion in the heating system.