text: GW in line circulation heaters also come with the choice of horizontal or vertical mounting depending on your application. Applications involve using a pump that flows the liquid through a closed pipe circuit (IE. water or glycol solution) that is reheated. A major consideration for this application is viscosity. Heat that is generated by the oil heater allows the liquid to be viscous enough to pass through the circuit of pipes. Circulation heaters come in a range of watt densities that are specifically designed for the medium that is heated. The required wattage to heat the oil or water is highly correlated to the flow rate (in GPM). The oil or water enters through an inlet (the inlet closest to the flange heater) and gets heat applied to it as it flows within a vessel chamber and exits the outlet nozzle (or flange) where it circulates throughout the piping circuit. Insulation is often required for vessels in order to preserve the heat to be applied within the vessel. Efficient heat application can often reduce unnecessary costs through heat loss.