In referencing a cooling tower, why does the drain continuously bleed water out of the pan?

In referencing a cooling tower, why does the drain continuously bleed water out of the pan?

• A. To Prevent Corrosion
• B. To Equalize Pressure
• C. To Keep Water Hardness To A Minimum
• D. To Vent Air

Answer: (C)

In a cooling tower, water evaporates and leaves dissolved minerals behind, so the remaining water becomes more concentrated over time. If you don’t remove some of that water, minerals like calcium and magnesium build up, causing scale that reduces heat transfer efficiency and can lead to fouling. Continuously bleeding water from the pan purge these dissolved solids, lowering the hardness and total dissolved solids to maintain proper concentration and keep the system running efficiently. Makeup water then replaces what evaporates and what is bled, keeping the balance. The other options aren’t the primary purpose: the bleed isn’t mainly to prevent corrosion, to equalize pressure, or to vent air.

In a cooling tower, water evaporates and leaves dissolved minerals behind, so the remaining water becomes more concentrated over time. If you don’t remove some of that water, minerals like calcium and magnesium build up, causing scale that reduces heat transfer efficiency and can lead to fouling. Continuously bleeding water from the pan purge these dissolved solids, lowering the hardness and total dissolved solids to maintain proper concentration and keep the system running efficiently. Makeup water then replaces what evaporates and what is bled, keeping the balance. The other options aren’t the primary purpose: the bleed isn’t mainly to prevent corrosion, to equalize pressure, or to vent air.