Why Does My Hot Tub Have a 'FLO' Error?

If your tub is displaying this message it simply means that there is an issue detecting water flow. This may occur for a number of reasons. On your spa’s heater, there are sensors that read water flow. These determine the error. The most common reasons for the FLO error message are dirty filters, a low water level,  clogged heater tube or inoperative spa pack.


How do I figure out what's wrong? 

1 - The first thing to do is to ensure your filtration pump is functioning normally.

First, power the tub off for 30 seconds and then back on. Self Cleaning tubs and Conventional tubs filter water differently, so choose the correct option below to verify your pump is functioning as intended. 

  • Self Cleaning Tubs: After waiting about 2 minutes, without turning on any of the jet pumps or touching anything on the keypad you should see small bubbles coming from the footwell of the tub. 

If you do see these bubbles, your circulation pump is functioning normally. Proceed to Step 2. 

If you do not see these bubbles, your circulation pump is not running and likely needs to be replaced. This is the cause of the FLO error.  Contact us to have the pump professionally replaced or for parts pricing and availability. See our guide on Replacing a Pump if you wish to replace it yourself. 

  • Conventional Hot Tubs (Serenity, Dreammaker, Sunrise): when approaching the tub, ensure all pumps are turned off. 

    • Press the Pump 1 button one time. You should have water moving inside the tub. Confirm water movement by placing your hand in front of some of the jets. 

    • Continue to press the Pump 1 once more. You should have water moving throughout the tub much more vigorously now. (high speed) 

    • Pressing the Pump 1 button once again should turn the pump off. Wait at least 10s before repeating these steps as pressing too quickly will skew your results. 

If the behaviour of the pump exactly follows the above,  move on to Step 2. 

If not, it is very likely that your pump is the cause of the FLO code. Most commonly, the pump will work only after the second press (high speed).  or the pump will not turn on at all. The FLO error occurs when the tub is trying to heat which happens on low speed only. The Pump 1 must be replaced. See Replacing a Pump for more information.  

2 - The second thing you should do is check your tub’s water level.

Top it off with water to bring the level to about 2 inches above the highest jet. Simultaneously, remove your hot tub's filter. After completing this, power the tub off and then back on and wait 15 minutes to see if the error reappears. 

If the error persists, continue to Step 3.

If not, it was likely the fault of a dirty filter or low water level. Maintain that water level and clean or replace your filter before installing to ensure the error message doesn’t pop up again. 

3 - The third thing to do is to inspect the heater tube sensors for a blockage.

Sometimes things such as leaves, hair and plastic can get caught on the sensors, causing faulty readings. To inspect the heater tube, the Spa Pack must be partially removed from the hot tub.


Step 3A - Stop the water 

Remove the safety clips and close the knife valves on each side of the spa pack.

Closing these valves will isolate the pump allowing you to disconnect the spa pack without draining the hot tub. Push the valves closed about 98% of the way.

If the valves are rather old, sometimes they can become stuck in the 'closed' position. You do not want it to become stuck as the only fix is to replace the valve. Therefore, it is better to lose a little bit of water instead.

Step 3B - Disconnect water connections from heater

xe5 spa pack

This is quite a simple task which may at first appear complicated. 

First, the two black split nuts on either side of the spa pack must be unscrewed from the coupling. (Don't remove the small philips screws from the split nuts unless absolutely necessary) The use of an oil filter wrench will make the process easier if connections are extremely tight.

Step 3C - Turn the spa pack to gain acess into the silver heater tube

flo code hydropool

Then proceed to remove the two screws in the base of the spa pack. 

Then carefully twist the spa pack, being careful not to pull or damage any wires, to an angle to where you can inspect the inside of the heater tube. Using a flashlight will make it much easier to spot any debris. 

If a blockage is found, a coat hangar bent into a hook can be extremely helpful in dislodging the debris. Ensure the heater tube is completely cleaned before reinstalling the spa pack. Use a garden hose to rinse it if required. Repeat Step 3 in reverse order to reinstall spa pack. 

If no blockage is found, proceed to Step 4.

4 - The final possibility is an inoperative spa pack. Either message us to schedule a service call and have it professionally replaced or view our guide on replacing a spa pack and replace it yourself! Contact us with your Spa Pack's model number for spa pack pricing and availability. 

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