Pentair IntelliFlo & SuperFlo VS Alarm Codes Explained

Every verified alarm on Pentair IntelliFlo, IntelliFlo3 VSF and SuperFlo VS pumps — including the notorious 0021 comm error — with what it means and what's safe to try yourself. We're Perfect Catch in Largo, the Pinellas County company licensed for the electrical side of these pump repairs (EC13011994, CPC1459998).

IntelliFlo & IntelliFlo3 Named Alarms

On these drives a red light means the pump has stopped on an alarm; a yellow/warning condition means the pump keeps running while telling you something. Here's each one.

Blocked System / Suction Blockage — pump shut off to protect itself

The drive detected the pump dead-heading or a blocked suction line and shut off within about a second (on SVRS-equipped models this is the entrapment-detection safety doing its job). Usual causes: a blocked skimmer or main drain, a closed valve, or a packed pump basket.

Try this first:

• Open and verify the suction-side valves
• Empty the skimmer and pump baskets
• Clear visible debris from the skimmer
• Restart the pump

Priming Failure / Priming Alarm — pump couldn't verify prime

The pump couldn't confirm prime within its "Max Priming Duration." It alarms for 10 minutes, retries, and after 5 consecutive failures locks out until Reset is held. Causes: low water level, an air leak at the pump lid o-ring, a suction-side air leak, or a closed valve.

Try this first:

• Top off the pool water level
• Check the pump lid is hand-tight and its o-ring is seated and clean
• Empty the baskets and open the valves
• Press and hold Reset once

Overheat / Drive Temperature — electronics too hot

The drive electronics exceeded about 130°F. The pump first derates (slows itself down), then stops if it can't shed heat. Direct afternoon sun, blocked vents, a dead cooling fan, or a hot equipment room are the usual causes — common on Florida pads in summer.

Try this first:

• Clear leaves or objects blocking the drive's vents
• Note the pattern — it often runs normally again after cooling in the evening, which tells the tech a lot

Over-Current — motor drawing too much

The drive tripped to protect itself from excess motor current — typically debris jamming the impeller, mechanical interference, low or bad supply voltage, or an aging motor.

Try this first:

• Empty the pump and skimmer baskets
• Power-cycle at the breaker once

Over-Voltage — supply above range

Supply voltage went above the drive's range — or, interestingly, the pump is being spun backward by water flowing through it while off (water draining downhill turns the motor into a generator). A utility spike or wiring problem can also cause it.

Try this first:

• Note when it happens — during storms? while the pump is off? — for the tech

Under-Voltage / Power Out — supply below range

Supply voltage dropped below what the drive needs, so it shut down. Voltage drop on the circuit, loose lugs, brown-outs, or undersized wiring are the usual causes.

Try this first:

• Check whether other equipment on the same panel is affected
• Note the time of day it happens

Internal Error / Internal Fault — drive self-check failed

The drive's software self-monitoring caught an inconsistency — a firmware glitch or failing drive hardware.

Try this first:

• Clear the alarm and restart once

Derating Alarm / "Exceeded and Cut Off" (IntelliFlo3)

The motor couldn't reduce speed enough to protect itself from a sustained heat or load condition and stopped. Run the same checks as the Overheat alarm — clear the vents, note the time-of-day pattern.

Thermal Mode — not a fault

The pump is running itself based on drive temperature to prevent freeze damage. This is normal protective behavior — yes, even in Florida cold snaps. Nothing to fix, and don't switch the pump off at the breaker during a freeze.

Speed / Pressure / Flow Limit warnings

The pump hit a programmed maximum and is self-limiting while it keeps running. A dirty filter raising system pressure is the classic cause of a pressure limit; aggressive schedule settings cause the others.

Try this first:

• Clean the filter if the pressure limit is showing
• Note which limit is displayed

Weak Wi-Fi / Offline (IntelliFlo3)

App-connectivity warnings only — the pump still runs its schedule. Router distance, antenna obstructions, or a power or Wi-Fi outage are the causes.

Try this first:

• Reboot your router and move obstructions
• Re-pair the pump in the Pentair Home app

SuperFlo VS Numeric Fault Codes

0021 — keypad lost communication with the motor board

The most-searched SuperFlo VS code. The communication link between the keypad (HMI) and the motor-control board dropped. The classic cause is moisture intrusion or a loose 5-pin connector on the jacketed cable behind the keypad, under the drive's top cover — corrosion on those pins is very common on outdoor pads near salt air.

Try this first:

• Power-cycle at the breaker: off until the keypad LEDs go completely dark, then back on
• If 0021 returns, stop — don't open the drive cover

Other SuperFlo VS codes: 0002, 0004, 0006, 0008, 0009, 000A, 000F, 0016, 0017, 001A

These are mostly internal drive protections. In brief:

• 0002 — absolute phase current limit exceeded (internal drive error)
• 0004 / 0006 / 0008 — power module, PFC, or diode-bridge temperature limit exceeded (drive overheating internally)
• 0009 / 000A — DC bus over-voltage / under-voltage (supply spike or sag)
• 000F — absolute AC under-voltage: supply dropped below ~99V (utility sag, loose connections, undersized circuit)
• 0016 / 0017 — phase current imbalance / offset out of range (internal diagnostics)
• 001A — power module over-current: usually a rotating-assembly problem like an impeller jam or seal drag

Try this first (any of the above):

• One hard power cycle at the breaker
• For the temperature codes, clear debris from the drive vents first
• For 001A, empty the baskets before the power cycle
• For 0009/000A/000F, note when it happens — brown-out timing helps the diagnosis

RS-485 "Comm Error" — pump and automation not talking

Any Pentair VS pump on EasyTouch, IntelliTouch or IntelliCenter automation can show a communication error. Causes: loose or reversed green/yellow RS-485 wires, a damaged comm cable (landscapers and rodents are repeat offenders), electrical noise, or a failed comm port.

Try this first:

• Power-cycle the automation panel breaker once

Why Homeowners Across Pinellas Call Us for Pentair Pumps

• Voltage faults need an electrician (EC13011994): over-voltage, under-voltage and 000F codes point at the supply — panel connections, wire sizing, brown-outs — and that's licensed electrical work we do in-house.
• Salt air and lightning country: corroded keypad connectors behind 0021 errors and surge-damaged drives are everyday finds on Pinellas equipment pads.
• Pool-licensed too (CPC1459998): when the real problem is hydraulic — suction leaks, blocked lines, an undersized filter — the same truck fixes that side as well.