Common Spa Side Error Codes

Below are some of the most common spa side error codes and there possible causes. For the complete list of error codes click here. For further troubleshooting click here.

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  • FLO, FL, FLC, FL1, PS, Blinking Lights
Pressure Switch or Flow Switch Failure. The codes above are all related to flow issues or the pressure switch/flow switch and are the most common error codes. These error codes can be caused for several different reasons. The main reason is water flow through the spa control system, if water is not flowing at a rate to satisfy the pressure switch, it will result in one of the error codes above. The first thing you want to do before doing anything else is shut the spa down, remove the filter and make sure all the jets are open. Then power the system back up, if the error code goes away, the problem was either a dirty filter (clean or replace) or too many jets were closed off. Other issues that can cause these error codes is debris wrapped around the pump impeller, or one of the valves is not open up all the way. The most common valve; the tee handle valve, will show that the handle is up, but in many cases the gate is still half closed, make sure that it is open all the way, you may need to dismantle the fittings to look inside. The final problem could be the pressure switch/flow switch itself. You can check the switch by performing the test below. Shut the power down, remove the two wires to the pressure switch/flow switch, find some sort of wire to join the wires, but don't do it yet. Turn the power back on, you have five seconds to join the wires together, do not join them before you turn the power on. Once this is done check ACROSS the heater element post, you should have either 110 volts or 220 volts depending on what voltage is operating the control box. If the error code goes away and you are getting the proper voltage then replace the pressure switch/flow switch. Also try it this way, Unplug the wires from the pressure switch/flow switch, turn on the pump and then jump the wires. FINAL NOTE: Most spas are equipped with pressure switches and can be found threaded into the stainless steel heater manifold. Flow switches are plumbed in line with the plumbing. You can also check the pressure switch or flow switch with a an Ohm meter. When the water is not flowing it should be OPEN, not CLOSED, if it is closed replace it.
  • OH, OHH, OHS, OHt, HL, HiLi, Sn2, Sn3, tS, Ht, Blinking Lights

Temperature Sensor Failure. The error codes above are related to a temperature sensor failure, overheat problems or a flow problem. If your spa is in fact overheating then it is caused by one of two things, either the temperature sensor is defective or the relays on the circuit board that operate the heater are stuck shut causing and over heat issue, in this case you would need to either replace or repair the circuit board. For information regarding repairs click here If your spa is not overheating and you are getting the above error codes then a couple of things could be happening. Depending on where the temp sensor is mounted; usually in the wall of the spa in a sensor mount, you could have a flow issue. Shut the spa down, remove the filter and make sure all the jets are open. Then power the system back up, if the error code goes away, the problem was either a dirty filter (clean or replace) or too many jets were closed off. In most cases overheat issues are related to the relays on the circuit board, or the temp sensor has failed and will need to be replaced.

NOTE: Temperature sensors should be mounted in a sensor mount in the wall of the spa and not behind the shield on the heater manifold with the hi limit sensor. The temp sensor is the larger of the two silver bullets.

FINAL NOTE: Balboa M7 systems have the Temperature Sensor as well as the Hi Limit sensor installed in the heater assembly, one at each end. Both are secured with black plastic nut around the gray cable. If one of these sensors needs to be replaced BOTH should be replaced at the same time. See M7 Sensors here.


  • SN, Sn1, Sn2 Sn3, HL, E1, E3, Prh, HtS, Blinking Lights

Hi Limit Sensor Failure. These error codes are similar to the ones previous, however we will be looking at these at another angle. Once again these can be caused by a flow issue. The first thing you want to do before doing anything else is shut the spa down, remove the filter and make sure all the jets are open. Then power the system back up, if the error code goes away, the problem was either a dirty filter (clean or replace) or too many jets were closed off. Other issues that can cause these error codes is debris wrapped around the pump impeller, or one of the valves is not open up all the way. The most common valve; the tee handle valve, will show that the handle is up, but in many cases the gate is still half closed, make sure that it is open all the way, you may need to dismantle the fittings to look inside. At the same time this test is being done, put your hand on the stainless steel heater manifold, it should NOT be hot, it should only be at the same temperature the water in the spa is. If it is hot you have a flow issue, or if it stays hot after the pump is shut off either the pressure switch has stuck close (see FLO error codes above) or the relays on the board have stuck shut sending continuous power to the heater. If all these test are checked and they did not solve the error code issues, then it is possible you have a defective hi limit sensor.

NOTE: The Hi Limit Sensor is located behind a shield on the stainless heater manifold and is the smaller of the two silver bullets. See picture below for reference

FINAL NOTE: Balboa M7 systems have the Temperature Sensor as well as the Hi Limit sensor installed in the heater assembly, one at each end. Both are secured with black plastic nut around the gray cable. If one of these sensors needs to be replaced BOTH should be replaced at the same time. See M7 Sensors here.