Every time the pumps shut off I get a FLO code. Where do I find the flow switch

FLO stands for flow switch open. If the pump is running and you have water flow it may be that the flow switch is not working properly. If your pump is not pumping water then you may have an air lock in the system.

Hi Simon,

The FLO message is a warning that your water flow is not what it needs to be. This can be harmful to your equipment, without proper water flow the heating element can over heat or your pump can run dry causing damage. Often this is can be caused by dirty filters, so your first check should be to see if your filters are clean. Other possible problems could be water levels. Make sure you have no water blockages especially on the suction end.

If you are seeing OH and FLO codes, you need to shut it down at the circuit breaker, until it can be serviced. It likely needs a new circulation pump and the flow or pressure switch may be failing to shut down the heater causing the boiling

Flo = Improper flow or pressure switch malfunction or Flow switch malfunction (system specific).

Before you purchase a new pressure switch:
- Clean or replace your filter cartridge (if its older than 1 yr).
- Check that all slice/gate valves are up/open.
- Check water lines for blockages incl. suction cover & ensure sufficient water level in spa.

Hello,
FLO code relates to the correct water pressure flowing through the heater tube. This is a safety procedure in adequate water flow could damage your equipment.
As this code can be one of the hardest to diagnose start by checking that all water suction & discharge slice valves are all-the-way open. If they are okay try clean or replace the filter cartridge.
If the cartridge is new or clean try temporarily run the spa with out the filter cartridge, it could possibly be preventing flow.
If the issue persists you can check that the suction fitting covers are free of debris. If the suction fittings are clear of blockages it is likely that pressure switch or flow switch (depending on your spa model) has failed.
These steps will fix a flo code the majority of the time, the pump is another potential cause but least likely.

The problem is that the flow switch for your water heater is indicating no flow. Therefore your water heater will not operate. Without proper water flow your heater will burn up. Check that your valves are open. Check that your pump is running. Check that your filters are properly installed and not restricting flow. Check the wiring to your flow switch and make sure the flow switch operating properly (i.e. put a ohm meter across the contacts and see if you have continuity when the switch closes).

LF means "Low Flow". Remove the filters to see if the code goes away. If not, the pressure switch may be bad.

you may have a bad pressure switch.if you are getting flow thru the heater and this code is comeing on there are only two reasons.No flow or bad switch.

Yes a pump does have a thermal cut out. When the motor gets too hot the thermal cut out will activate and the pump won't restart until the motor has cooled.


If you were an electrician, or highly confident/competent with electrics, you could test the motor with a volt meter. Run the spa and as soon as the pump stops running, check the voltage at the pump. If there is voltage at the pump, then the thermal cut out on the motor has activated. Do not try checking this yourself if you're not competent to do so.

You could also do the same test at the spa pack if it's easier to do so, just locate the output to the pump.

What spa and which spa pack have you got?

Cheers,
Ian.