What salt system error codes actually mean

What is the panel actually measuring?

Very little of what it displays is measured directly. A salt chlorinator knows the voltage it is applying to the cell and the current the cell is drawing, and it knows water temperature from a sensor. Almost every warning on the display is derived from those numbers.

That matters because current through salted water is a function of several things at once: salt concentration, water temperature, plate surface area and plate condition. The panel cannot tell those apart. It sees resistance and reports a conclusion.

So the correct posture toward a salt panel is to treat every warning as a starting point rather than a diagnosis. It is a reasonably honest witness reporting a symptom it does not fully understand.

What does a low salt warning usually mean?

In winter, temperature. Cold water conducts less than warm water at the same salt concentration, so a system that read comfortably in October can throw a low salt warning in January without a single grain of salt having left the pool. Many units compensate for this and many compensate imperfectly.

The second cause is a scaled cell. Calcium bridging the plates reduces effective surface area, current falls, and the panel reports the drop as low salt. Cleaning the cell frequently makes the low salt warning disappear entirely, which tells you what it really was.

The third is an aging cell with worn coating, which reduces conductivity for the same reason and produces the same warning.

The rule that saves the most money here: never add salt on the strength of a panel reading alone. Confirm with a salt test strip, a drop titration kit or an independent meter. Salt is easy to add and impossible to remove without draining and refilling with hard water, so this is a measure twice situation.

What does a no flow or check flow message mean?

It means the system is not confident that water is moving through the cell, and it will refuse to generate chlorine until it is. That refusal is protective. Producing chlorine gas in a cell full of still water is a genuine hazard, which is why this interlock exists.

The causes run from the trivial to the real. A dirty filter, a clogged pump basket, a pump running at too low a speed for the flow switch to close, a valve position that has changed, or an air pocket at the cell will all produce it.

Variable speed pumps cause this constantly and it is worth calling out. A schedule programmed for quiet efficient filtration can sit below the minimum flow the salt system needs, so the pool filters beautifully and generates no chlorine at all. If your salt pool went green after a pump upgrade, this is very likely why.

A flow switch can also simply fail, or its paddle can be fouled or stuck. That is a real fault and it is diagnosable, but it should be the fourth thing you check rather than the first.

What does an inspect cell or service light mean?

On most systems it is an hours counter rather than a measurement. The unit counts production hours and lights up when it reaches a threshold, prompting you to look at the cell. It is a reminder, not a diagnosis, and it will illuminate on a perfectly healthy cell.

Some units combine that with a genuine output check and will report low output separately. Where those two are distinct, the output warning is the meaningful one.

Either way the response is the same and it is easy. Pull the cell, look through it at daylight, and decide whether you are looking at scale, at worn plates or at a clean cell that simply hit a counter. That five minute look answers a question the panel cannot.

What you should not do is clear the reminder and carry on for another year. The counter exists because cells in hard water do accumulate scale on a predictable schedule, and here that schedule is faster than average.

Which codes mean stop and call?

Anything reporting high current, a shorted cell, a power supply fault or a board error. Those describe an electrical condition rather than a water condition, and the equipment is telling you it has a problem inside the box.

Anything that returns immediately after a cleaning and a confirmed correct salt level. Repeating a fix that did not work is a way of paying twice for the same afternoon.

Any warning accompanied by a burning smell, discoloration at the cell connections, a melted or brittle cell cord, or a breaker that trips. Salt cell cords carry real current and they do fail at the connector. That is an electrical fault next to water and it should be handled, not investigated.

And a persistent no flow with a clean filter, correct pump speed and correct valves, because at that point you are looking at either a failed switch or a genuine flow restriction inside the plumbing.