Ask The General: How Do You Prime the Pool Pump?

The General tells you how to prime the pool pump Dear General;

Everyone keeps telling me I have to prime the pump for my fiberglass pool. That’s all well and good. My question to you is, how in the heck am I supposed to do it? And how do I know when it’s done?

Signed– In a Perplexed Pool Pump Priming Pickle in Peru.

Dear Perplexed;

No need to be in a pool priming pickle. Honestly, I get this question all the time. You’re not alone. Let’s break this down together.

First of all… Let’s take a look at how water circulation systems work.

The key, believe it or not, is atmospheric pressure. There are approximately 14 pounds of air pushing down on all of us all the time. That means there’s the same amount of pressure pushing down on the surface of your fiberglass pool water. Your pool pump has a something called an “impeller” that creates a low pressure area by spinning. It pulls water into it, and pumps it back into the pool.

A “closed system” means NO AIR

Here’s the secret that explains it all. Your pool needs to be a CLOSED system to operate. Your pump, all your piping and everything that’s involved with the transferring of water from the pool into the pump, to the filter and back into the pool has to be full of water with NO AIR. A closed system is one that has NO AIR in it. All you have to do is stop and think “Where can air be introduced into the system?” (Did I mention NO AIR?)  

Pool Pump Priming Checklist

Once we’re sure we have a closed system, check the following things:

  1. Check your water level. If there’s air coming through the skimmers (Remember NO AIR?) it will make you lose prime, so you need to ensure you have proper water levels. Normally, the ideal water level is about halfway up the middle of your fiberglass pool’s skimmer or a little higher.
  2. Check the skimmer’s “weir door”. The weir door is the little flapper in the mouth of the skimmer. If you see a clogged, full skimmer basket, clean it out.
  3. Clear debris from main drain and check the piping at the equipment area. Make sure there is nothing that can allow air in, even things like the cap on the pipe used for winterization. It may need to be re-Teflon taped. Unions and ball valves may also need to be tightened.
  4. Check the pump itself. Make sure pump is turned off, then take the lid off the pump basket, clean the pump basket and return it to the pump. Fill the basket with water and securely close the lid on the pump. Open the ball valves in front of the pump. (Before turning the pump on, I normally check the rest of the system to make sure the water can run through it.)
  5. Check the valves. Make sure the valves are in the positions recommended by the manufacturer (usually instructions are on the filter.) Some filters (such as cartridge filters) don’t have veriflow valves, but they all have starting instructions. If you can’t find the instructions, look online. 

Show time!

Once you’ve made sure everything is tightened, the return eyeballs (inlets) can allow water into your fiberglass pool, the drain plugs are secure, and the pump basket has been filled, it’s show time. Flip the pump switch. Did it start? If no, don’t despair, and don’t say bad words. It’s going to be okay.

Try this little trick:

Turn the switch off and check the GFI breaker in the electrical panel that controls the pump. Is it tripped? Flip the switch again. Are you in business now? Hallelujah!

Time to enjoy!

Now follow the manufacturer’s directions to put the system in “filter” mode. You will see the filter gauge rise to normal pressure. Water will be flowing into the pool, water will be spinning over the weir door into a full skimmer, no air will be coming out of the inlets, the pump basket will be clear of air, and you will have successfully primed the pool pump.

Now it’s time to grab a float and your beverage of choice and enjoy the pool.

Until next time…

The General


Who is The General?

The man, the myth, the legend….we just call him The General. His organized, systematic approach to pool installations over the years had his crew members calling him “The General” and it stuck. The General has over 30 years’ experience in the pool and spa industry, working for one of Pool and Spa News’ Top 50 Pool Builders.”

Over that time, he designed, sold, project-managed and installed over a thousand inground swimming pools. As a pool owner himself, he’s the perfect authority to give you the inside scoop, with amazing tips and tricks to make pool ownership a breeze!