Gas Fitter Practice Test

What monitors water flow in a pool heater?

1. Aquastat

2. Low water cut off

3. Pressure switch

4. Flow switch

The correct answer is: Pressure switch

The correct choice for monitoring water flow in a pool heater is the flow switch. A flow switch is specifically designed to detect the movement of water within the system. When water flows through the heater, it activates the flow switch, which can then signal the heater to operate. This mechanism ensures that the heater runs only when there is adequate water flow, preventing potential damage to the unit, such as overheating or burning out, which could occur if the heater were running without sufficient water to circulate. In contrast, the other options serve different functions. An aquastat typically monitors and regulates the temperature of the water rather than the flow. A low water cut-off is designed to shut off the system when water levels are too low, ensuring safety and preventing damage. A pressure switch measures the pressure of the water but does not directly monitor its flow. Therefore, while pressure and temperature are important aspects of a pool heating system, the flow switch is uniquely responsible for directly monitoring the flow of water in a pool heater.