Swimming Pool pumps can sometimes give you problems. In fact, one of the broadest questions we're asked is "how do I get my pump to work again? It's not sucking water." If your pump isn't working you've got to go step by step in order to diagnose it. There are 2 general reasons for these problems: Mechanical or Physical.
The Mechanical reasons are pretty simple to diagnose. Does the pump turn on? If no, it could be one of several reasons. First make sure it's plugged in. Make sure the circuit breaker is turned on and if you have a timer attached (good idea in order to save money), make sure that you are currently in the "ON" zone.
Next, check the wiring. If the wiring is somehow defective due to age improper installation, the pump & motor will not turn on. It would be well worth your while having a local pool service technician or electrician diagnose the problem. If the pump is more than 5 to 7 years old, it is coming to the end of its useful life and may need to be replaced. Electric motors do not last forever.
CAUTION! Whenever working on or examining the electric motor, be sure that it is UNPLUGGED and not just shut-off. You don't want to be injured with an electrical shock.
If you turn the motor on and it hums, there are a couple of things to check. First off, when starting in the spring, it's very possible that a little bit of corrosion has formed on the magnetic wiring. In this case, usually a simple turn of the motor shaft by either turning the impeller directly (motor unplugged with no electricity) or by removing the back plate of the electric motor and turning the shaft. After you have made sure it is moving freely and smoothly, plug the motor back in and turn it on. This cures 95% - 99% of this type of problem.
The Physical reasons are sometimes a little more time consuming to diagnose. Here the questions center around, "the pump won't prime" or "the motor runs but the basket doesn't fill up with water" or "the pump is operating but it's not pulling anything."
All of these issues can be relatively simple to fix and will most likely NOT require a professional service call. Follow the following steps:
Make sure there is enough water in the pool. If the water isn't high, a "whirlpool" will form in the skimmer and air will be drawn into the system. While you're in the skimmer, make sure the basket is free of leaves and debris.
Is the filter dirty or otherwise clogged? If so, backwash the sand, change the DE or clean the cartridge. If water cannot flow through the filter, the pump will not be able to draw water.
On aboveground pools utilizing blow molded hose, be sure there are no kinks in the hose.
On inground pools, it is possible that a larger object such as an acorn or wad of leaves or dead frog or mouse, has gotten past the skimmer basket and is clogging an underground pipe. In this case a pipe snake may be needed to remove the object (the most unlikely cause of all on this list).
Make sure the pump basket gasket is clean & well lubricated with a good quality silicone lube. Clean off any dirt or leaf particle. DO NOT use vaseline or petroleum jelly; either product will shorten the life of the gasket or O ring.
Make sure the pump basket cover is not cracked or misshaped. If so, it will not seal.
Make sure the clamps on the hoses are properly tightened (mostly on aboveground pools). Too loose & air will be allowed in plus you'll notice leakage. Too tight & the hose will be pinched with the same problems.
Check any valves for leaks in general - air leaks in particular. On the suction side of the pump you will NOT have any water leaks when the pump is operating; when turned off, there may be a few drips. Change or replace any valve gaskets. At the beginning of each swimming season, be sure to lubricate the gaskets & O rings.
Put a bead of silicone calk around each pipe connection. Over time, some of the glued pipe connections can degrade allowing air to get into the system.
Take the pump apart & check to see if the impeller or diffuse (or both) are worn. Impellers and diffusers will wear due to normal erosion over time. Worn out impeller blades or veins will dramatically reduce the amount of water that a pump is able move.
While the pump is apart, remove any accumulations of debris from the impeller. Use a wire to clean out the areas between the impeller blades. Bits of leaves, twigs, acorns and seeds, as well as hair will clog the impeller impeding the flow of water; even a couple of tablespoonfuls of debris will make all the difference. Do this check mid-season and at closing for continued good performance.
The most likely causes? Worn or dried out gaskets & O rings and clogged impellers.