In an Air Handler, which component controls the flow rate of water through the heating coil?

In an air handler, the balancing valve on the heating loop is the component responsible for controlling the flow rate of water through the heating coil. This valve is designed to adjust the amount of water that circulates through the heating coil, ensuring that the correct flow rate is maintained for effective heating.

By managing the flow, the balancing valve helps to achieve the desired temperature and efficiency of the heating system. It allows for proper distribution of the heated water, which is critical in maintaining a consistent and comfortable indoor environment.

While the thermostat plays a role in indicating demand for heat by signaling when the heating system should be activated, it does not directly control the flow rate of water. The relief valve is related to safety and prevents overpressure in the system, but it does not regulate flow. The circulator pump moves the water through the system but also does not control the flow rate. Thus, the balancing valve is key in manipulating thermal comfort and system performance in an air handler.