How to release an air lock in your spa

Massachusetts Coleman Hot Tub Dealer

Todays post is a follow up to last weeks spa start up article where i briefly mentioned the possibility of a spa air lock. Today we will look at 2 ways you can release an air lock in your spa.

One of the more frustrating problems you can face when trying to start up your hot tub after a fresh fill is an air lock. You’ve spent all that time cleaning out the tub and waiting for it to fill up and when you finally go turn turn the jets on you get nothing. You can hear the jet motors coming on but there’s no flow coming through the system.

Video: How To Avoid an Air Lock In Your Spa

Spa air locks come in varying severities and there are a couple of ways to remedy this issue. One preventitive method I talked about in my last post on spa start-up involved putting the hose into the filter well as you re-fill the tub allowing water to fill the spa plumbing easier. This way we can take to try an avoid the hassle of an air locked hot tub in the first place.

Yet even when we try to prevent the dreaded air lock it still happens. Here are a couple ways to release the air lock and get on with enjoying the hot bubbly goodness!

Burp the spa like a baby:

Remove spa jets to clean

  1. open all jets by turning the faceplates counter-clockwise
  2. Turn down heat so heater does not try and fire
  3. Press jet to turn on jets, twice for high speed, let run for 10-15 seconds
  4. Repeat step 3 a total of 3 times increasing run time by 10-15 seconds each time
  5. Once you see air bubble starting to be released from the jets leave jets running until all air is released

If the air lock is not severe you can sometimes release it by simply “burping” the system. Before you do this you want to make sure all of the individual jets are completely open by turning the jet faceplate clockwise as far as they will go. This will make sure there is no added resistance on the system and the air and water can escape from the jets uninterrupted.

One more thing before we start turning the jets on is to make sure the heat is off, either by turning the heat off at the control panel or turning the temperature down as far as it will go, this way the heater wont try to kick on when there is no water flow as that can damage the heater.

How to burp a spa to release air lock

To burp the system all you are going to do is quickly turn the jets on high for 10 seconds and then turn them off, if you have two jet buttons make sure you do this with each jet zone. Do this 3 times and you should see the amount of air bubbles coming out increase each time you turn them on. Keep burping the jets increasing the length of time you hold the jets on by 10 seconds each time. Eventually the whole system will burp and a huge blast of air bubbles will rush out of the jets. If this happens, congratulations you have released the air lock the easy way!

Now if during your initial attempts you see no increase in the amount of air bubbles coming out of the jets or worse no air bubbles at all coming out of the jets you have a severe air lock and you should STOP the “burping” process. The reason you need to stop burping the system if this happens is because if you continue to run the pumps dry you could damage them. This is when we move on to the next method for releasing an air locked hot tub.

Releasing an Air Lock From The Pump Area

bullfrog spa pack releasing and air locked hot tub

  1. Remove front panel of spa (usually philips head screwdriver is needed)
  2. Locate large union nut connecting spa plumbing to motor
  3. Loosen nut on pump by hand or using a large set of channel lock pipe grips
  4. Once water starts leaking out all air has been released, you can now re-tighten the union nut
  5. Turn on jets and see if problem has been resolved

If the burping procedure above is not working we need to release the air lock at its source, for that we need to remove the front panel of the spa. Behind the front panel is where all of your spa equipment is located as seen above in this Bullfrog Spa, most spa cabinets just use 4 Philips head screws.

Air locks happen when we fill the hot tub from inside the tub and water falls into the plumbing from the jets, this pushes all the air that is in those lines back to the spa equipment. This air is then trapped between the suction and pressure sides of the system on either side of the jet motor. Therefore the easiest way to release this air pocket is to crack open the union nuts on the spa motor itself.

Where the plumbing connects to the spa pump will be a big white union nut threaded onto the wet end of the motor. You will probably need a good size pair of pipe grips to loosen the union nut, but sometimes you can loosen them by hand. When you loosen the union nut enough you should hear the air escaping.

Once all the air has escaped out of that union water should leak out and you should be able to start the jets right up without any further problems.

If you have any questions regarding these spa air lock solutions please feel free to leave a question in the comments below or email me directly at: Thanks for reading and don’t forget to subscribe to the blog on the top right of this page.

About the Author


Jay is the retail sales manager at Precision Pool Construction and has been running the store for the past 9 years. He has been in the pool and spa industry for the last 15 years and is CPO certified by the National Swimming Pool Foundation.In addition to his pool and spa experience, Jay is an accomplished solo singer/songwriter who has been featured on various Boston radio stations and has played in some of the areas best music venues. Check out the tunes hereConnect with Jay on Google +


  1. thank you for the help you have to provide for me. i would like some more information about hottubs. some have speakers and subwoofers and the one i have wont work i have tryed many types of i-pods and mp-3 players, the wires are all hooked up, i also would like to get a layout of the hot tubs you sell on pipes, wires and more thank you very much. just please send that to my e-mail

  2. Frustrated with an air lock and unable to loosen the union nut so I tried your burping method; it worked! Thanks so much. You saved me from an expensive service call.

  3. Thanks Diana,

    I am glad that we could help you out with that and thank you very much for taking the time to post about your experience.


  4. Thank-you for posting this information and including pictures. I was able to find my Union nut and burp my spa successfully! And I’m a girl!

  5. Our circulation pump is not really moving water so the heater shuts down. It tries the first 10 sec. or so, then silent. It sounded like there’s air, bubbles or debris trapped in there. Is this an airlock issue and should we try as you suggested?

  6. Hi Kay,

    I apologize for the delay I have been away.

    Sounds like you might have debris that got sucked into the circ pump, I have seen that happen. You really need to open up the wet end of the circ pump and see if you can get rid of some of that.


  7. Hi, I Have a Cal spa 2006 Model # M-06-v800-42. Like Kay, When my circulation pump tries to kick on, it only hum’s for a few seconds, then shuts off.
    What’s different is, if I’m at my hottub controls when then happens, I can hit the high (jets) button, and it takes right off. I can leave it on high for only a split second, then back to low (circulate) and it works just fine until the next time it tries to automatically circulate.
    Is it a debris problem for me as well??
    THANKS in advance!

  8. We have tried burping and leaking the water from the union nut. The most we get may be some gurgling. It ran a long time before we noticed the jets on one side wasn’t working. Is there permanent damage? What now?

  9. Did you just re-fill the spa and that pump has not worked yet or did that pump just start having problems out of the blue? If you have tried all of those things you could have a bad pump.

  10. Hi! We have a FLO error. Our repair guy has replaced the circ pump, flow switch, and control panel. It works after each repair for about 10 minutes and FLO comes back on. It comes on for it’s four cleaning cycles and FLO comes back on. If we turn it off at the box and turn it back on we can then hit the jets and enjoy it for it’s 20 minute cycle and then FLO comes back on when the cycle if finished. Any ideas?

  11. Have you tried running the spa without the filters in it and seeing if the FLO error comes on? If it does it sounds like the flo switch relay on the pc board is bad and may need a new pc board as you have changed everything else.

    Try running it without the filters could be the answer a new set of filters could be the answer.

  12. I have a leisure bay G-3 series hut tub. When I turn on the tub, all jets are working but after a couple of minutes the tub shuts down and I get a dr display. What could be the problem and how do I fix it? Thanks!

  13. I have a Sundance Altamar hot tub. It has FLO on screen. I have replaced the FLO switch replaced the filters and it is still on any sugestions

  14. Hi Janis,

    Pumps are running as normal? DO you check that the 24 hour circ pump is running and running properly.


  15. I just filled my 2000 whirlpool Jaquzzi and jet pump works but I’m getting a LF and not circulating well. I tried loosing the the nuts on both pumps and still nothing. Could it be debri? The circulation pump is working,

  16. I had to burp my spa last year and recently I noticed the water level dropping. I’ve isolated a leak at the union nut shown in the center of the picture you have above. I’ve hand tightened it as much as I can. Do I just need to keep trying to tighten it to stop the leak, or is there another solution?

  17. CLose your slice valves and undo the union completely. There is a gasket inside the union, go to your local pool store and ask for jacks lube, or silocone lubricant. Grease up that gasket and then tighten it making sure not to cross thread. It should be a quarter turn past hand tight.


  18. We just filled our hot tub and the jets were working at first and now we can’t get them to work. We tried unscrewing the screw on top of the filter and turning on drain valve which has no pressure by the way. What else can we do? Thank you in advance.

  19. Hi Tracey,

    If the jets were working when you first filled the spa and they stopped working, that is not an air lock that is something wrong with the spa. Could be overheating. Are there any error messages on the board?

    Do you hear the motors turn on when you hit the jet buttons, but now water comes out? Or do you hit the jet buttons and nothing happens at all? No sound, nothing?

    This might be something you will need to troubleshoot

  20. I hope u can offer some insight. We have a 2009 hot springs spa, envoy kk, we knew the original owner who took care of his things. He moved and we were happy to get it from the new owner. Moved it a half mile, placed it, wired it, filled it, getting power to where it should b. I have circulation pump and ozone. Not sure about heat. Obvious problem is the jet pumps do not work. They don’t run, hum, get warm….nothing. I have power coming through the control board and up to the 2hp pump motors. Contacted spa service company who said it may be an air lock. Would an air lock stop a motor from turning on.? I can’t beleive two pumps would fail the exact same way at the same time. I’m frustrated and the service company cant get here for 3 weeks.

  21. If the motors are turning and huming but no flow is coming out of the jets it is most likely air locked. It is unlikely that both pumps would be siezed but I suppose it is possible. Crack the unions on the front of each pumpp until water comes out then screw the union back on and fire them on again and see what happens.

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