Pentair SuperFlo VS Priming Failure

Priming failure is the most common field issue on the SuperFlo VS. The pump automatically enters priming mode at startup and runs at up to 3450 RPM for up to 5 minutes while attempting to establish water flow. If priming fails, the pump stops and must be diagnosed before restarting.

Unlike the IntelliFlo, the SuperFlo VS does not have a "priming alarm" fault code — the pump simply fails to move water and may stop or run dry. Diagnosing the cause before restarting is critical to avoid seal damage.

How SuperFlo VS Priming Works

When the pump starts from a stopped state (except Quick Clean mode), it runs at the programmed priming speed — 3450 RPM by default — for up to 5 minutes. During this time, the screen cycles between the current priming speed and remaining priming time.

If the priming speed is reduced below 1700 RPM during the priming window, priming mode is disabled and the pump transitions to the scheduled speed immediately.

Common Causes

Air Leaks on the Suction Side

Air enters the system and prevents the pump from building suction:

• Worn or damaged lid O-ring (most common)
• Cracked or loose pump lid
• Loose union connections on suction line
• Worn valve stem O-rings on suction gate valves
• Cracked suction piping

Insufficient Water

• Pool water level below skimmer — pump draws air through skimmer
• Strainer pot not filled before startup
• Closed or partially closed suction valve

Clogged Components

• Blocked strainer basket
• Debris in impeller
• Clogged skimmer basket

Step-by-Step Troubleshooting

Step 1: Check Water Level

Pool water must be at least halfway up the skimmer opening. If low, add water before attempting to restart.

Step 2: Inspect the Lid and O-Ring

1. Stop pump and turn off power at breaker
2. Tap the lid clamp counter-clockwise to remove
3. Lift the lid and inspect the O-ring for cracks, flat spots, or debris
4. Clean the O-ring and sealing surface; lubricate O-ring with silicone lubricant
5. Check lid for cracks — replace if damaged
6. Reinstall lid and rotate clamp clockwise until handles are horizontal

Step 3: Fill the Strainer Pot

1. Remove the lid
2. Fill the strainer pot with water up to the inlet port
3. Reinstall lid immediately and tighten clamp
4. Open filter air relief valve
5. Stand clear of filter — start pump
6. Close air relief valve once steady water stream appears

Step 4: Verify Suction Valve is Open

Confirm all suction-side valves are fully open. A partially closed valve prevents priming even with a full strainer pot.

Step 5: Inspect for Air Leaks While Running

With pump running, look for:

• Air bubbles visible through the see-through lid
• Water spraying from fittings or unions
• Hissing sound near suction connections

Step 6: Adjust Priming Speed

The default priming speed is 3450 RPM. After starting the pump:

• Use the + and − arrows to adjust priming speed between 1700 and 3450 RPM
• Higher priming speed generates more suction — useful for long suction runs or elevated installations
• Dropping below 1700 RPM disables priming mode entirely

Priming Speed Settings

Note: Unlike the IntelliFlo, the SuperFlo VS does not have adjustable priming duration — priming always runs for 5 minutes at the set speed.

When to Replace Components

• Lid O-ring (P/N 357255): Replace if cracked, deformed, or doesn't seal after lubrication
• Lid (P/N 350091): Replace if cracked or warped
• Mechanical seal: Replace if pump leaks between motor and volute — indicates dry-run damage
• Strainer basket (P/N 355667): Replace if cracked

Related Guides

• SuperFlo VS Troubleshooting Guide
• Pump Won't Start