How to Prime a Pool Pump: a Step-by-Step Guide

By
Ralph Tarulli
Ralph Tarulli
Ralph Tarulli
Ralph Tarulli is a pools and construction expert with 7+ years' experience working on pools, and 10+ years' experience in commercial construction. He has 15 professional certifications and is pursuing a career in building engineering.
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Published on 03/31/23
how to prime a pool pump

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Project Overview
  • Working Time: 2 - 30 mins
  • Total Time: 2 - 30 mins
  • Skill Level: Beginner
  • Estimated Cost: $0

Priming a pool pump involves getting watering flowing through the pump in advance of turning it on. It is important for a pump to always have water in it while working because the pool pump uses the water to cool it during normal operation. Without water in your pump or if you run your pump while it is not fully primed, you could potentially damage your motor or melt your pump housing leading to costly repairs.

A pool pump needs to be primed anytime it is emptied. This can mean at the beginning of pool season, after a repair, or any other time air is introduced into the system. Here's our easy guide to priming a pool pump.

What Is a Pool Pump?

A pool pump is a pump that pulls water from your pool and forces the pool water out towards the filter to be cleaned and returned to your pool.

Assess the Water Level Before Priming

The difficulty of priming a pump depends on its location in relation to the water level of the pool. Your pool pump sucks water from one location and forces it to another location under pressure. This means that the inlet side is under a vacuum (i.e., it sucks water in) and the outlet side is under pressure (i.e., it pushes water out). This is why if you have an air hole or leak in the inlet side between your pump and skimmers you will see air bubbles in the motor basket and your pump will most likely make a noise similar to rocks rolling around inside, meaning that it's not fully primed.

Check the height of the water relative to the pool pump. If your pool pump is below the water level, it should be able to prime itself with minimal effort because gravity will do the work for you. When priming below the water level, the water will flow to the lowest point and go to the pump naturally.

A trickier situation is if your pump is higher than your water level. This is more challenging because in order for the pump to suck the water it will need help grabbing it. Poop pumps are not very good at sucking up water through the air. The solution is to introduce water where there is air so the pump can grab the water and suck it into the impeller to prime itself.

Warning

Above all, never stick your hands in the impeller no matter what when working with any kind of pump. If you absolutely have to, be sure that the pump is physically disconnected from its power source so there is no chance of it starting up while your hand is inside.

What You'll Need

Equipment / Tools

  • Bucket

Materials

  • Water

Instructions

How to Prime a Pool Pump

  1. Fill the Housing

    • Valve off your pump if you can. The inlet side is more important since this is where the water will go once you put water in the pump basket to help prime it.
    • If done correctly, the pump housing should be filled and the lid should be on tightly.

    Remember that you are introducing water to where air is so the pump can grab the water and pull it. This is a lot easier with a valve because it will stop the water from flowing back into your pool.

    Tip

    If your pool setup does not have a valve before the pump, put water into the pump basket and shut the lid tight immediately after. This will stop the water you just put in from spilling down the inlet pipe and leveling out with the water level of your pool. In effect, you are raising your water level inside the pipe and shortening the distance your pump has to pull the water to get into the pump housing.

  2. Set the Multi-Port and

    • Set the multi-port to filter and check that all valves are open to allow water flow.

  3. Run the Pump and Watch

    • Turn on the pump and watch for water to come out of the inlet side and spill into your pump housing. This can be seen through the clear lid on most pumps. Initially you will see the water in the basket get sucked out quickly — this is normal.
    • Once the initial water gets sucked out, look for water to come through the inlet side of the pump into the pump housing. This will indicate if it is working or not.

    Tip

    If you have a valve before your pump and the pump is higher than your water level, you can crack your valve open slightly and use it as a throttle. This will limit the amount of air your pump will suck up at once and will hold its prime for longer until gets to 100% prime.

  4. Watch the Pump Fill With More Water

    • If you see a small trickle of water come from the inlet side into your basket this means that the pump is able to grab the water slightly. Most of the time if the pump is left on it will gradually be able to overcome the air in the system and will prime itself.
    • You will know when your pump is fully primed when you see what is called a “double cyclone” in the clear lid and there is no more air coming out of your return.

  5. Repeat As Necessary Until Water Comes Out of Inlet

    • If the pump doesn't start sending out water after 10 seconds or you do not see any water entering from the inlet side after the initial basket of water gets sucked out, turn the pump off and close all valves, and refill the pump housing. Don't let the pump run while dry.
    • Repeat the first four steps until you get water to come out of the inlet side.

When to Call a Professional

If you cannot get your pump primed at all or it loses its prime, it is best to call a professional. Either of these situations would indicate that you have air coming into your lines somewhere and it will have to be traced out and repaired.

FAQ
  • How long does it take for a pool pump to prime?

    It should take a pool pump from one second to 20 seconds to prime. If it does not prime in this time, there is still air in the line.

  • What should you do if your pool pump won't prime?

    If your pool pump will not prime, try adding water to your system. If it still does not prime, it means that air is getting into your piping somehow. If there is no evidence of a leak or crack, you will need to call a professional.

  • How do you get air out of a pool pump?

    To get air out of the pool pump, open the pump housing and fill the basket area with water. Then quickly close the lid to catch as much water as possible before it flows into the pool. There is also often a bleed valve on top of the filter that can help remove air from the filter and aid in priming the pump.