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Pool Pump Plumbing Connections

The plumbing connections on a new pool pump installation must be done correctly to ensure proper operation of the pump. If there is any air leaks in the connections to your pump then the system will not function properly or cause premature failure of the pump shortly in the future.

Starting with the basics, the suction side of the pump is the port directly next to the strainer lid and strainer basket where the water enters into the pump. The top port of the pump which is usually located about in the middle of the pump, usually pointed upwards, is the discharge port of the pump. This is the port that will connect to your filter.

The first connection that you should make when hooking up the pump is the suction port. It is very important not to interrupt the flow for the pump by putting fittings or valves directly in front of the ports. Follow the guidelines in the video above to make sure you do not starve the pump or cause it to work harder than it should be as this will cause early failure.

Pool Pump Sizing

When you install a pool pump you need to be sure that the pump is sized properly for the specifications of the pool and the plumbing system configuration. The pool pump and filter needs to turn over the entire volume of water a minimum of 2 times every 24 hours and ideally 3 or 4 times every 24 hours.

Minimum turnover rates are not hard for an average pool pump to meet and exceed. A common problem is to have a pool pump that is too powerful. Turning over the water too much is not the problem. The problem is that if the pump is too powerful for the supply plumbing lines this will result in cavitation of the pump.

Pool Pump Cavitation

Cavitation is a complicated fluid process that happens in centrafugal pumps like swimming pool pumps. Simplified, the speed that the water enters into the pump is different than the speed of the water adjacent to the center of the impeller. This speed differential creates a pressure differential that results in air bubble formation as the water is turned to vapor. The vapor bubbles are then sent towards the outside edge of the impeller where it loses its stability and suddenly collapses.

This vapor bubble collapsing causes microscopic damage to the impeller of the pump as well as cause a violent shaking / surging reaction in the pump. Even this simplified description is too complicated for most pool pump installers. Cavitation happens when the pump is pulling in water faster than water can be supplied by the system. When the pump cavitates it will rock or shake abruptly followed by a loud hissing / shaking noise.

If you have cavitation in your pump then you have either installed a pump that is too large for your plumbing lines or filter, have a blocked or partially blocked suction line, or have the isolation valves on either the suction or return lines closed. A pump can not sustain long periods of cavitation without causing damage or total failure to the pump internals.

Learn more about Pool Pump Priming for both above grade and below grade installations. There is also more information on Pool Pump Plumbing connections on the home page.

Pump Fact

Most pump leaks develop from improper installation - Tighten only hand tight plus 1/4 turn for threaded pool pump connections to avoid cracking the pump housing.