Cooling towers, chillers and heat exchangers all depend on a circulation pump that runs for thousands of hours a year. A well-chosen pump saves electricity and rarely fails; a poorly chosen one wastes power and trips the plant. This guide covers the main choices.
What a cooling-tower pump does
It circulates water between the cooling tower and the equipment that needs cooling, such as a chiller condenser, a process heat exchanger or an industrial furnace. The duty is steady, the flow is large and the head is moderate, so single-stage pumps with efficient hydraulics are the best fit.
Work out flow and head
Flow is set by the heat load: the more heat to remove, the more water is circulated. Head is the sum of the pipe and fitting losses, the pressure drop through the condenser or heat exchanger, and the height of the tower distribution system. Include a small margin, but avoid heavy oversizing.
Vertical or horizontal layout?
- LLT / LLTS (vertical): a compact upright pump with horizontal inlet and outlet. It takes little floor area and suits tight plant rooms. The LLTS version has an extended shaft for easier service.
- WLT / WLTS / WLTSF (horizontal): axial suction and radial discharge, easy to maintain and to align. The WLTSF version has a stainless steel casing and cover for a smoother flow passage.
Choose the layout that matches your space and maintenance practice. Both are single-stage, single-suction, non-self-priming pumps designed for circulation duty.
Materials and water quality
Cooling water carries dissolved salts, treatment chemicals and sometimes sand. Check the casing material, the shaft and seal materials and the maximum liquid temperature against your water treatment. Stainless parts last longer in aggressive or treated water.
Installation tips
Keep the suction pipe short and straight, fit a strainer, and make sure the pump sits below the minimum tower basin level to avoid air entry. Use isolating and non-return valves on each pump, and consider a duty and standby pair so the plant never stops.
Frequently asked questions
How do I choose between LLT and WLT?
Use LLT when floor space is tight and a vertical pump fits. Use WLT when you prefer a horizontal pump that is easy to align and service.
Do I need a standby pump?
For critical cooling, yes. A duty and standby pair keeps the plant running during maintenance or a failure.
Can I run these pumps with variable speed?
Yes. A variable-frequency drive can match the flow to the load and cut power use, provided the minimum flow of the pump is respected.
Talk to CNP Pumps Pakistan
Compare LLT and WLT models, or send us your flow and head.
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