If the pressure in your swimming pool filter looks correct, but the water doesn’t seem to be moving through it very quickly, it could be that your pool pump’s impeller is clogged.
The easy way to determine if the water is moving slowly is to take a look at your skimmer: the water should be gushing into it. If it’s sluggish, chances are pretty high there’s an issue with your impeller.
This procedure is performed on an A.O. Smith Century series pump. Pool pump manufacturers vary, and their methods of attaching the pump to the filter system can also be quite different. But, this should give you at least an overview of how to clear the impeller.
Turn Off Pool Power
First, turn off the power supply to pump. Don’t just turn off the timer – turn off the circuit breaker (1) that powers the timer. You don’t want the pump turning on while your fingers are in it. If you don’t know which breaker is which, turn them all off. Better to be safe than sorry.
Disconnect the Pump
Next, disconnect the pump from the filter system. To do it, you will need to release some sort of clamp – this pump has a band clamp (1). Use a socket wrench (2) to release the nut (3) on the clamp, and split it open. Water will gush out from both the filter side and the pool side of the pump.
Remove the Band Clamp
You many need to use a flat-bladed screwdriver (1) to gently push the band (2) away from the pump. Don’t push too hard, but work the blade under the clamp until it pops up. Do this for the other side of the clamp, too.
Remove the Impeller Cover
Pull the pump away from the filter flange, and turn it so that the impeller cover (1) points directly up at you. You can rest the back end of the pump motor on the ground. Use your screwdriver (2) to remove the screws (3) from the impeller cover. Don’t unscrew the screws completely, just enough so that the cover comes loose from the pump. Lift the cover off of the impeller and set it aside.
Clean the Impeller
The impeller blade (1) is typically clear so that you can see if the vanes are plugged. This pump has a thick wad of leaves and twigs wound up in it. Use a pair of needle nose pliers (2) to remove the blockage. Keep working at it until you get all of the debris out of the impeller.
Check Pump Bearings
Turn the impeller blade with your hand. It should turn freely. If it doesn’t, you have an issue with your pump motor and need to consult a professional.
Install Impeller Cover
Put the plastic cover over the impeller blade, and align the screw holes. Put the screws into the holes, and tighten them down. Now, this is important: don’t tighten down the screws in series, one after the other. Tighten one (1), then tighten the screw on the opposite side (2). Skip the screw to the left of that, and then reach back across to tighten another screw (3). Go around the pattern (4, 5) until all of the screws are tight. This is described as tightening in a star pattern, and it reduces stress on the plastic cover and helps to keep from breaking it.
Examine the O-Rings
Take a look at the O-ring (1) on the impeller’s tip. It should be smooth, with no gaps or breakages.
Check the O-Ring (1) on the filter’s flange. This one is a compression ring – it’s tightly compressed to fit into the flange. It should be clean and smooth, without any cracks or breaks. Make sure to clean away any debris from these O-rings.
Reconnect the Pump
Slide the pump (1) into the flange (2), pushing it as tightly as it will go.
Install the Band Clamp
Fit the band clamp (1) around the outside of both the pump and the flange, and tighten the nut.
The band clamp has a v-shaped inner side (2). As you tighten the nut, the faces of the vee push against the flange and pump (3), forcing them together.
Use a piece of wood (1) and a hammer (2) to gently tap the band clamp (3). Put the wood against the clamp near the bottom of the pump and gently tap it with the hammer. Don’t hit it hard – just be gentle. Don’t strike the pump, and don’t strike the band clamp with the hammer. Gently tap the wood, driving any looseness in the clamp towards the buckle. This helps the band clamp tighten more completely, and equalizes the pressure it exerts around the circumference of the flange.
Use your socket wrench (1) to tighten the nut (2) as far as it will go: be careful not to tighten it so far as to strip it. If that does happen, take the nut with you to your home improvement center, and compare it to fine-threaded nuts – it’s important to use fine-thread. This pump uses a 28 pitch nut.
Prime the Pump
Prime the pump by adding water to the secondary filter to replace the water that was lost. Now, with that done, turn on the breaker and start the pump.
If the impeller was clogged, you’ll see an immediate improvement to your water flow.
Congratulations! You did it!