When a Pentair IntelliFlo stops, slows down or flashes a red light, it's usually protecting itself and telling you why. The older IntelliFlo VS and VSF show the alarm on the pump's own control panel; the newer IntelliFlo3 shows it in the Pentair Pool app, your automation panel or a touchscreen, with a colored light on the drive. Here's what each alarm means, how it resets, and what to check first, from Pentair's own manuals.
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An IntelliFlo alarm is the pump's drive stopping or slowing the motor to protect itself, and naming the reason. Pentair's manuals describe these alarms by name, such as Priming Failure or Overheat, and separate them from warnings, which let the pump keep running.
On the IntelliFlo VS and VSF, a red alarm light comes on, the control panel buttons are disabled, and the Reset button clears the alarm once the cause has been fixed. On the IntelliFlo3, the drive's ON/STOP light tells you the state:
| IntelliFlo3 light | What it means |
|---|---|
| Green, solid | Pump running |
| Green, blinking | Priming cycle |
| Green, pulsing | Pump in Thermal Mode |
| Red, blinking | Alarm detected; the pump stops until it is resolved |
| Green/yellow, blinking | Warning detected; the pump keeps running |
| Yellow, solid | Pump is idle |
| Red, solid | Pump disabled |
| Alarm | What Pentair says it means | What to check |
|---|---|---|
| Priming Failure | The pump didn't prime within its maximum priming time. On the VS and VSF it stops, shows a Priming Alarm for 10 minutes and tries again; after five failed attempts it sets a permanent alarm that must be reset by hand. The IntelliFlo3 guide puts it down to a lack of water in the strainer pot | Water level, the strainer pot, lid and lid O-ring, a clogged basket and air leaks on the suction side |
| Overheat | The drive is too hot. On the VS and VSF, above 130°F the pump slowly reduces speed until it cools; IntelliFlo3 blames a blocked cooling fan inlet or outlet or very high air temperature | A clean fan guard and room for air to move around the motor |
| Drive is Derating / Derating Alarm (IntelliFlo3) | Derating is a warning: the pump slows to keep the drive from overheating. If slowing down isn't enough, the Derating Alarm stops it, and it restarts by itself once it cools | Same as Overheat |
| Over Current | The motor is working too hard. IntelliFlo3 lists debris, part interference, temperature, age of parts or supply voltage; the VS and VSF manuals say the drive is overloaded or the motor has an electrical problem | Debris in the impeller or strainer; anything inside the pump is a technician job |
| Over Voltage / Under Voltage | Supply voltage is outside the proper range. The IntelliFlo3 clears the alarm and resumes once the voltage is back to normal | A licensed electrician if it keeps happening |
| Internal Fault / Internal Error | An internal hardware or software error in the drive | IntelliFlo3: cut power for a minute and reconnect. If it stays, call a professional |
| Speed, Pressure or Flow Limit (warnings) | The pump has reached a programmed maximum and can't hit its target. IntelliFlo3 measures total dynamic head, so its pressure won't match your filter gauge | The limit settings, and a dirty filter or clogged basket that makes the pump work harder |
Pentair also notes that the VS and VSF won't start if the impeller is already turning, and that after an over current or over voltage fault clears they restart on their own after 20 seconds. The IntelliFlo3 tries to restart a minute after an over temperature or over current fault.
Pentair asks you to keep the pool about halfway up the skimmer opening. When the level falls below it, the pump pulls air through the skimmer, loses its prime and runs dry, and Pentair warns that running dry damages the shaft seal and makes the pump leak. In a Houston summer, evaporation can drop the level surprisingly fast, which is why a priming alarm after a hot, dry week is often just a low pool.
On an IntelliFlo3, the priming settings (speed, duration, delay and range) can be adjusted if a healthy pump struggles to prime; Pentair's defaults are 100% speed, an 11-minute maximum and a priming range of 5. Our guide to a pool pump losing suction covers the debris and air leaks behind most priming problems.
An IntelliFlo that slows down on a hot afternoon and recovers when it cools is doing exactly what it was designed to do. Pentair's fixes are practical: on the IntelliFlo3, keep the fan guard clean and blow out dirt and debris with compressed air; on the older pumps, increase ventilation and reduce the air temperature around the motor. Leaves, grass clippings or anything stacked against the motor can block the airflow.
When it keeps stopping instead of just slowing down, the cause is more likely inside. Pentair's troubleshooting points to debris in the impeller, a rubbing impeller, wrong voltage or loose wiring, and on the IntelliFlo3 a noisy pump can mean debris touching the cooling fan. Those checks need the power off at the breaker and the pump opened up, so that's where we come in.
IntelliFlo pumps have a Thermal Mode that runs the motor when the drive gets cold. Pentair is clear that it protects the pump, not your pool: the sensor is inside the drive, so it may not reflect the actual air temperature, and Pentair says not to rely on it alone for freeze protection. On the VS and VSF, the pump's own thermal protection is turned off when it's connected to an automation system, and freeze protection comes from the automation instead. See our guide to freeze protection settings before the first front.
Call when an alarm keeps coming back after the checks above, when the pump runs but moves less water than it used to, or when it leaks from under the motor; Pentair calls the shaft seal a wear part that needs replacing after long use. Most of our pump repairs fall between $150 and $400. If the drive or motor has failed, Pentair sells those as separate parts on many models, so it isn't automatically a new pump; our guide to replacing the motor or the whole pump explains the choice, and a new variable-speed pump is typically $2,000 to $2,400 installed.
If yours is running fine but you want to know what the speed settings save, see pool pump energy savings. If you have a Hayward pump, see our guide to Hayward pump error codes; for a Jandy, see Jandy VS FloPro faults. For everything else, see pool pump repair.
The pump didn't prime within its maximum priming time. On the IntelliFlo VS and VSF it waits 10 minutes and tries again, and after five failed attempts it sets an alarm you have to reset by hand. The usual cause is not enough water: a pool below the skimmer opening, an empty strainer pot, a clogged basket or an air leak on the suction side.
Fix the cause first. On the VS and VSF, the Reset button clears the alarm once the fault has been resolved. On the IntelliFlo3, voltage alarms clear on their own when the voltage returns to normal, and for an Internal Fault Pentair says to disconnect power for a minute and reconnect. If an alarm keeps returning, have the pump checked.
It's protecting its drive. On the VS and VSF, once the drive passes 130°F the pump slowly reduces speed until it cools, and the IntelliFlo3 does the same with a Drive is Derating warning. Keep the fan guard clean and give the motor room to breathe; if it stops completely and keeps doing it, call us.
Several alarms restart automatically. The VS and VSF restart 20 seconds after an over current or over voltage fault clears, the IntelliFlo3 tries again a minute after an over temperature or over current fault, and a priming alarm on the VS and VSF retries after 10 minutes. Repeated stops point to a cause worth fixing.
On the drive's ON/STOP light, solid green means running, blinking green is priming, pulsing green is Thermal Mode, blinking red is an alarm (the pump stops), blinking green and yellow is a warning (the pump keeps running), solid yellow is idle and solid red means the pump is disabled.
Tell us the model and the alarm it's showing. If it's water level or a dirty basket, we'll tell you so; if it's the seal, the impeller, the drive or the motor, we'll come out and fix it. Licensed, insured, serving Cypress and Greater Houston.