Pentair IntelliFlo VSF Priming Failure

The priming failure alarm on the Pentair IntelliFlo VSF indicates the pump was unable to establish prime within the configured maximum priming duration. This is an alarm condition — the red alarm light illuminates and all control panel buttons are disabled until the alarm is cleared.

How the Alarm Works

If the pump is not defined as primed within the Max Priming Duration, it will stop and generate a Priming Alarm for 10 minutes, then attempt to prime again. If the pump cannot prime within five attempts, it will generate a permanent alarm that must be manually reset by pressing the Reset button on the control panel.

Causes and Corrective Actions

Air Leak in Suction (PRIME ERROR may be displayed)

Check suction piping and valve glands on any suction gate valves. Secure lid on pump strainer pot and be sure lid gasket is in place. Check water level to be sure skimmer is not drawing air.

Not Enough Water

Be sure the suction lines, pump, strainer, and pump volute are full of water.

Pump Does Not Come Out of Priming Mode

Adjust the Priming Range to a higher setting (default setting is 5). A higher range allows the drive to detect prime with less water flow.

Pump Completes Priming Mode Too Early (Air Still in Housing)

Adjust the Priming Range to a lower setting (default setting is 5). A lower range requires more water movement before the pump will exit priming mode.

Pump Strainer Basket Clogged

Clean the pump strainer pot. The strainer basket must be kept clean and free of debris — dirty baskets reduce flow and prevent proper priming.

Pump Strainer Gasket Defective

Replace the lid gasket. A defective gasket allows air to enter the pump housing, preventing the pump from establishing prime.

Priming Menu Settings

The following priming settings can be adjusted from the operator control panel by pressing Menu and navigating to Priming:

Setting	Default	Range
Priming Enable/Disable	Enabled	Enabled / Disabled
Priming Speed	3450 RPM	2400–3450 RPM
Max Priming Duration	11 minutes	1–30 minutes
Priming Range	5	1–10
Priming Delay	20 seconds	1 second–10 minutes
Loss of Prime	Enabled	Enabled / Disabled

Max Priming Duration

This setting is the amount of time the pump will try to prime before it gives a priming error. The maximum priming time can be set from 1 to 30 minutes (default: 11 minutes). If the pump does not prime within this time, fill the pump basket with water and restart the pump.

Priming Range

Priming range can be set from 1 to 10 (default: 5). The smaller the range, the more water the pump must be moving to detect that it is primed. At larger ranges, the pump will detect that it is fully primed while moving less water. If the range is set too high, the pump may exit priming mode before it has fully primed. The range will automatically adjust with the priming set speed because flow rates will be lower at lower speeds.

Priming Speed

The priming speed can be set between 2400 RPM and 3450 RPM (default: 3450 RPM). If the pump is on an equipment pad close to the water level, it may not need to run at maximum speed to successfully prime. Day-to-day factors such as local ambient pressure, water and air temperatures, and the amount of water retained from the last system run can affect priming performance.

Loss of Prime

When enabled (default), this feature allows the pump to recognize unanticipated low-flow or no-flow situations while running a program. The pump will pause for one minute after detecting a loss of prime, then attempt to re-prime. If priming is successful, normal operation continues. If not, the pump will continue attempting to prime until prime is achieved or a priming error occurs.