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How To Fix a Hot Tub Air Lock

By Matt Giovanisci | Updated: January 19, 2021

Have you ever turned on your hot tub and the jets refused to, well, jet? There’s nothing coming out. No water, no air, no nuthin’. A hot tub without working jets is basically a very expensive bathtub, so you’ll no doubt want to fix this right away. But just what the heck is going on?

Sounds like a hot tub air lock. And no, we’re not talking about the air lock you’d find on a spaceship. You’ve got air in the plumbing lines. But that’s OK, because we’ve got a line on how to fix it so you can get back to soaking without all the swearing.

What Is a Hot Tub Air Lock?

To understand why your spa isn’t working, you first need to understand how it’s supposed to work. Very simply:

  • The tub is full of water, and the water line is above the skimmer.
  • The pump is on.
  • The part of the hot tub pump called the impeller pulls water from the tub via the skimmer.
  • The water passes through the filter and on to the pump.
  • The water passes through the pump and is pushed into lines that lead to the hot tub jets.
  • Water is pushed back into the hot tub via the jets, and continues to circulate through this process, as long as the pump is running.

If you turn on the pump, but little to no water comes out of the jets, you have a hot tub air lock.

The most likely time for this to happen is when you drain and clean your hot tub every quarter. You do, right? Right.

When you drain the spa, water doesn’t just come out of the tub. It also drains from the pump and the plumbing lines, which power the jets.

Then you refill the tub. As the water rises and reaches the jets, theoretically, it should run into the jets and refill the lines as well. But that doesn’t always happen.

Instead, the air that has replaced the water in the pump and jet lines creates a block, preventing the water from running into the lines. It’s a power struggle between air and water, and air often wins this one.

Once the hot tub is refilled and you turn the jets on, there’s no water in the pump or the lines, so there’s no water for the jets to push into the tub. This is bad because the water isn’t circulating the way it should.

But it’s really bad because you never want to run a pump with no water in it. Pumps are made to function with water. Without it, the pump’s motor could burn up, and it’ll cost you money to either repair or replace it.

But before it even gets to that point, you can easily fix a hot tub air lock yourself. All you have to do is prime the pump.

1. Burp Your Hot Tub Jets

Let’s start with the easiest of two methods. With just a few pushes of a few buttons, you can quickly fix a hot tub air lock. You won’t even need any tools for this one.

  1. Find the priming mode on the control panel if your spa has one. If it doesn’t, that’s OK; you can still use this method.
  2. Turn the jets on low for 10 to 20 seconds.
  3. Switch the jets to high for another 10 to 20 seconds.
  4. Repeat until the jets are working without any gurgling or air bubbles.

This is an easy fix, but it doesn’t always work. If, after trying this three or four times, the air lock still isn’t resolved, stop the procedure to avoid damaging the pump, and try the next fix.

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2. Expel The Air Directly From Your Hot Tub Pump

If burping the spa didn’t work, you can use the pump’s bleeder valve to expel the air and relieve the hot tub air lock.

You may need a couple of tools for this one:

  1. Turn off the hot tub GFCI breaker. You don’t want to make accidental contact with electricity from your pump. Like we always say, electricity and water do not mix.
  2. Open the access panel in the hot tub’s cabinet. You may need the screwdriver for this.
  3. Locate the pump, and close the gate valve on the discharge side.
  4. Slowly turn the bleeder valve until you hear air hissing out. You may need the pliers for this.
  5. Once the sound stops, tighten the valve. If you don’t tighten it, water can leak from it and cause problems, so be sure to replace it properly. Note: A little bit of water may leak from the valve when you do this. That’s OK. This actually tells you all the air has been released. Just tighten the valve so no more water can escape.
  6. Turn the breaker and spa back on to check the jets.

More Hot Tub Air Lock Tips

If you’re still having problems after priming the pump, you can try a few other hot tub air lock remedies.

  • Maybe it’s not air in the lines. Check for other things that can affect water flow such as clogs or leaks.
  • Clean the filter. If it’s filled with gunk, water will have a hard time passing through it.
  • Check the water level to make sure the tub is full. If the water level is below the skimmer, the pump may not be getting enough water.
  • Don’t give up after one try. Sometimes it takes multiple attempts to clear a hot tub air lock.
  • Never run the pump for more than 2 minutes if you aren’t absolutely positive it’s filled with water. If you see smoke, it’s too late. Don’t let it get to that point.

That oughta do it! But it still might not. In that case …

Call a Professional

So this is actually the easiest method, but it’s also the most expensive one. But if nothing you’ve tried has fixed the hot tub air lock, or you’re just not comfortable doing it yourself, don’t hesitate to call in a pro.

Unlock More Hot Tub Enjoyment

We wish we could tell you how to keep a hot tub air lock from happening in the first place. But it’s just physics, and there’s no way around that. It will definitely happen to your spa at one time or another, or many times.

But now you know how to handle it so it won’t be so frustrating when it does occur. And as for the other possible water flow issues, just keep your hot tub clean and well maintained, and those things you should be able to avoid.

Happy Soaking!

Matt Giovanisci is the founder of Swim University® and has been in the pool and spa industry since 1995. Since then, his mission is to make pool and hot tub care easy for everyone. And each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
A Cheat Sheet For Balanced Hot Tub Water and Crystal Clear Soaking.
Download this FREE printable cheat sheet to keep your hot tub clean and clear. You’ll never worry about your hot tub again with this easy-to-use guide.
Click Here For The FREE Cheat Sheet