How to Clear Your Impeller

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 the pool timers before you do this job.

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.

Remove the nut from the band clamp.

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.

Use a screwdriver to gently pry the clamp open.

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.

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.

Needle-nosed pliers are great for dragging out the stuff stuck in your impeller.

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.

The impeller should turn freely.

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.

Tighten the screws in a star pattern.

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.

Check the o-ring.

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 compression gasket.

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.

Push the pump against the faring.

Reconnect the Pump

Slide the pump (1) into the flange (2), pushing it as tightly as it will go.

Attach the band clamp.

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 block of wood and a hammer to tap the spaces out of the clamp.

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.

TIghten the nut on the clamp.

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 pump.

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!

Back to How to Swimming

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