What is the primary function of Pump 5 in a heating system?

The primary function of Pump 5 in a heating system as indicated by the correct choice is to circulate water in the heat recovery piping system. This process is essential for ensuring that the heat extracted from wastewater or other heat sources is efficiently transferred and utilized within the system.

In a heat recovery system, the primary goal is to reclaim energy that would otherwise be wasted and use it to preheat water or for other heating purposes. The pump plays a vital role in facilitating this by maintaining the necessary flow rate of water within the heat recovery piping, enabling optimal heat transfer efficiency. It ensures that the water carrying the recovered heat moves throughout the system effectively, maximizing the use of the energy recovered.

Options that reference other functions, such as supplying water to the boiler or increasing pressure, represent different roles that pumps can have in a heating system but do not align with the specific purpose of Pump 5 as identified in the context of the heat recovery process. Cooling functions also deviate from the primary intent of a pump dedicated to heat circulation. Therefore, understanding the specific role in relation to heat recovery is key to recognizing why circulating water is the primary function of Pump 5.