What must be monitored to prevent a feed water pump from becoming steam bound?

To prevent a feed water pump from becoming steam-bound, it's essential to monitor the temperature in the open feedwater heater. If the feedwater temperature rises too high, it can lead to a situation where steam is mixed with the feedwater, causing the pump to become steam-bound. When this occurs, the pump can struggle to move water effectively because steam occupies space and creates vapor lock, which can prevent the pump from generating the necessary pressure to push water into the boiler.

By closely monitoring the temperature in the open feedwater heater, operators can ensure that the feedwater is at an appropriate temperature before it enters the pump. This helps maintain optimal conditions for pump operation, ensuring that it can properly handle the liquid feedwater without interruptions caused by steam formation. Keeping the temperature within the recommended limits directly correlates to the efficient operation of the feedwater system, which is crucial for overall boiler performance and safety.