Hayward Pool Pump Not Priming or Losing Prime
- Low pool water below the skimmer
- Clogged impeller restricting flow
- Blocked main drain
Problem Description
The Hayward variable speed pump runs but the strainer basket does not fill with water, air bubbles are visible in the pump lid, or the pump loses prime after running for a few minutes. A pump that cannot pull water from the pool cannot circulate, filter, or chlorinate. Air leaks on the suction side are the most common cause — air enters the plumbing between the pool and the pump, breaking the vacuum the pump needs to pull water.
Why This Happens in Real Homes
A Hayward pump that will not hold prime is a suction-side air problem or a flow restriction almost every time. In real equipment pads the lid o-ring and a low water level below the skimmer are the top causes, with a clogged impeller close behind.
Fill the basket to prime, lube the lid o-ring, and set the water level before hunting a buried leak.
Symptoms
- Pump will not pull water into the basket
- Loses prime with air in the basket
- Bubbles at the returns
- Weak or no flow
- Basket water level drops while running
- Loses prime overnight
- Cavitation noise
- Primes then quits
Recognize these? Here's what usually causes it.
Common Causes
- Low pool water below the skimmer
- Clogged impeller restricting flow
- Blocked main drain
- Suction-side air leak
- Empty strainer basket at start
- Dried or bad lid o-ring
- Clogged skimmer or pump basket
- Closed suction valve
Most fixes happen in the first 3 steps.
Step-by-Step Solution
Check the pump strainer lid and O-ring
Turn off the pump. Open the strainer lid by turning it counterclockwise (on the TriStar VS, the lid has a large knob handle). Remove the lid and inspect the O-ring in the groove around the rim. If the O-ring is cracked, flat, or has gaps, it lets air into the pump. Clean the O-ring groove of debris and lubricate the O-ring with a thin coat of Teflon-based pool lube (not petroleum jelly — it degrades rubber). Reseat the O-ring in the groove and close the lid hand-tight. Do not over-tighten — the O-ring does the sealing, not the force of the lid.
Fill the strainer basket with water before starting
With the pump off and the lid open, fill the strainer basket housing completely with water from a garden hose. This gives the pump water to work with on startup so it can build suction. Close the lid. Turn on the pump at low speed (1100-1500 RPM on the TriStar VS). Watch through the clear lid — you should see water flowing within 30-60 seconds. If the basket empties and fills with air instead, there is a suction-side leak pulling air faster than the pump can pull water.
Inspect suction-side plumbing for air leaks
Air leaks between the pool skimmer and the pump are invisible when the pump is off because the plumbing is under suction (negative pressure) only when running. Common leak points: union fittings on the suction pipe (hand-tighten the union nut and check the O-ring inside), valve stem O-rings on diverter valves between the skimmer and main drain, the drain plug on the bottom of the pump housing, and any cracked PVC fittings. To find a suction leak, apply shaving cream around each joint while the pump runs — the cream will get sucked inward at the leak point.
Verify the water level and skimmer are not blocked
If the pool water level drops below the middle of the skimmer opening, the skimmer sucks air instead of water. Fill the pool to the middle of the skimmer faceplate. Also check that the skimmer basket is not clogged with leaves — a blocked skimmer restricts flow and can cause the pump to suck air through the weir door. Remove the skimmer basket and clear any debris. If you hear a gurgling sound from the skimmer while the pump runs, the water level or skimmer flow is the issue.
Check the main drain for blockage
If the pump pulls from both the skimmer and main drain, close the skimmer valve and try priming from the main drain only. If the pump primes from the main drain but not the skimmer, the suction leak is on the skimmer line. If it will not prime from either, the issue is at the pump itself (lid O-ring, drain plug, or union fitting). On the TriStar VS, the drain plug is on the bottom front of the pump volute — check that it is tight and the O-ring is intact.
Check for a clogged impeller restricting flow
If the pump primes but flow is weak and pressure is low, the impeller may be clogged. Turn off the pump and close the suction and return valves. Remove the pump lid and strainer basket. Reach into the volute opening (the pipe connection at the back of the strainer housing) and feel for the impeller. If you feel debris packed around the impeller vanes, pull it out. Leaves, hair, and plastic wrap are common culprits. On the TriStar VS, the impeller is accessed from the front through the strainer — you should not need to disassemble the motor to clear a clog.
Quick Solutions
Still having issues? This is usually the deeper cause below.
If this comes back after following these steps, check whether a recent app or firmware update reset a default setting — the fix works, but the setting gets reverted silently.
Hayward pump manuals are at https://www.hayward-pool.com/support/product-manuals — search by model (TriStar VS, Super Pump VS, MaxFlo VS). The TriStar VS manual includes the impeller access procedure and O-ring part numbers. Always use Teflon-based pool lube on O-rings, never petroleum-based products. Replace the strainer lid O-ring every 2-3 years or whenever it shows any cracking or deformation — a $5 O-ring prevents a $200 service call.
This issue almost always looks more complex than it is — the majority of cases trace back to a single setting, a stale credential, or a default that shipped wrong.
- Low pool water below the skimmer
- Clogged impeller restricting flow
- Blocked main drain
- Suction-side air leak
- Empty strainer basket at start
Before you go — try one of these (they fix most cases).
Official Manufacturer Manual
Hayward provides official product documentation through their online manual rather than downloadable PDF. Access setup guides, troubleshooting steps, and product specifications for your Hayward Pool Pump.
Source: hayward.com
Need More Help? Hayward Support
Note: The contact information below connects you directly to Hayward's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.