Hot Tub Flow Error – What is it?
A flow error on your hot tub is a sign that there is an issue with your water flowing through your heater in the hot tub. You can identify a flow error as it will display “FLO” on the front panel. Some common issues that can cause a flow error are:
- Lower than normal water levels.
- Damaged and/or dirty filter.
- Air inside and through your pipework.
- Faulty sensor and/or pump – not working.

Hot Tub Flow Switch Explained:
A hot tub flow switch is a mechanism that acts as a helpful safety device to keep an eye on the flow of the water throughout your hot tub.
If water flow is interrupted, it will turn the heater off to ensure that it stays in optimal condition and doesn’t damage any other surrounding equipment.

Common Hot Tub Flo Error Codes And What They Mean
FL1: Suggests your flow switch is stuck in the open position.
FL2: Suggest your flow switch is stuck in the closed position.
FLO: Suggests there is an issues with your water flow.
Most of these hot tub flo errors occur due to dirty or blocked filters, so make sure you take the time to maintain your filters in order to avoid hot tub flo errors.
Checklist For Troubleshooting Flow Error:
At first sight of seeing a hot tub flow error, there are a few initial things to check which may help you resolve the issue.
Check the following:
- Ensure the water in the tub is at the correct level, halfway up the skimmer basket opening and is covering all of the hot tub jets.

- Check that your filters are cleaned on a regular weekly basis as a build up of dirt and debris could be hindering the water from flowing freely through the hot tub.

- Find out when you last purchased a new filter to be used for your hot tub as over time, the fibres in the filter will break down which will hinder the flow of water. You should replace your filters every 12-18 months.

- Has the spa been drained and re-filled recently? If so, you need to make sure that when you fill with water you place the hose down the skimmer basket opening to get the pipes inside filled up first before the main section of the spa. Filling the spa up by leaving the hose in the middle could cause issues such as airlock – contributing to create a flow error.

- Finally, make sure that all of the jets are set to open and that the diverters are in the middle to get an even flow of water and air in the hot tub. Sometimes when turning the jets on and off/diverting water it can hinder the flow of the water around the spa – so making sure these are all open in the case of a flow error message is the best practice.

How To Fix The Hot Tub Flow Error:
There are a couple of solutions you can try to fix the flow error yourself; if these do not resolve the issue, then it could be signs that you have a faulty pump not pushing water through, or a bad pressure flow switch not working correctly. In this scenario, we recommend you seek professional help if it can’t be resolved after reading through the options. We offer hot tub and swim spa services as a one off treatment or an annual plan – get in contact to book your next service now.
Option 1: Raise The Hot Tub Water Level
Fill your spa up to the correct fill line in the middle of your skimmer basket if it is not already there. Then turn off the power to your spa and remove the filter. Wait around 15-20 minutes then turn the power back on, switching on the jets and seeing if it resolves the flow error.
If this clears the flow issue, you can then switch off the spa, replace the filter back then switch back on. If the flow issue comes back after replacing the filter, you now know that you need a new filter to be replaced.
Option 2: Check & Remove Airlock in Heater
Firstly, ensure that all jets are open on your spa. Then try running the jets without a filter in to see if it resolves the issue. If this is not successful, you should switch the spa off at the isolator, then run a hose pipe down the skimmer basket in attempt to get air pushed through to get rid of the airlock.