A pool pump losing pressure while vacuuming is a common problem faced by many pool owners. This issue can occur due to various reasons such as clogged skimmer baskets, a dirty filter, or a leak in the pump system.
If not addressed on time, this problem can lead to poor filtration, algae growth, and other issues that can affect the overall health of the pool. In this article, we will discuss the reasons behind the loss of pressure in the pool pump while vacuuming, and offer some tips on how to fix the problem.
Causes Of Pool Pump Losing Pressure
Pool pumps losing pressure while vacuuming can be frustrating for pool owners. There are several reasons why this could happen. Blocked suction lines can cause a decrease in pressure, preventing water from circulating properly. Another reason could be air leaks in the suction line, causing a decrease in pressure and air entering the system.
Checking skimmer and pump baskets for debris buildup is also important. Dirty or clogged baskets can reduce the water flow and cause the pump to lose suction. Lastly, any damage to the pump impeller or motor can result in decreased pressure and cause your pool pump to lose power.
Regular maintenance and cleaning can help prevent these issues and keep your pool pump running smoothly.
6 Common Reasons for Pressure Loss When Vacuuming
Air Leaks in the System
Vacuum Hose Leaks: The most frequent culprit is a hole, crack, or split in the vacuum hose. Air is drawn into the system through these breaches, disrupting the pump’s suction and causing pressure to drop.
Loose or Damaged Fittings & Gaskets: Worn pump lid O-rings, union gaskets, or winterization plugs can allow air in, especially when the vacuum increases suction demand.
Low Water Level: If the pool’s water level is below the skimmer intake, air enters the system, reducing pressure.
Air Not Purged from Vacuum Hose
Failing to completely purge air from the vacuum hose before connecting it to the skimmer or vacuum port introduces a burst of air, leading to loss of prime and pressure.
Obstructions or Clogs
Debris lodged in the vacuum head, hose, skimmer basket, or pump basket can restrict water flow and drop system pressure.
A clogged pump impeller can also cause weak suction; if you inspect and clean the baskets and line but still have trouble, check the impeller inlet.
Collapsing or Old Vacuum Hose
If your hose collapses under suction (seen as pinching or crumpling), water flow is restricted and pressure drops sharply. This is more likely in old, sun-brittled, or low-quality hoses3.
Test the hose integrity by visually inspecting for weak spots or holding it underwater while the pump is running.
Pump or System Underpowered
Rarely, certain pumps may be only just adequate for your pool size. The extra resistance added by a vacuum hose can make an underpowered pump lose pressure or fail to maintain a prime123.
Other Suction Leaks
Suction-side leaks (underground pipes, valves) may go unnoticed at normal flow but become problematic when the vacuum line increases suction.
Troubleshooting And Solutions
If you’re finding that your pool pump is losing pressure when you’re vacuuming, there are a few potential issues that could be causing this. One potential issue could be blockages in the suction line. To locate and identify these blockages, turn off your pump and remove the strainer basket and skimmer basket.
Next, insert a plumbing snake into the suction line to clear any debris. Another potential issue could be air leaks in the suction line. To identify these, run your hand along the suction pipe while the pump is running to feel for any leaks.
To fix air leaks, use joint sealant or teflon tape to seal the leak. Additionally, it’s important to regularly clean the skimmer and pump basket to prevent blockages. If you identify impeller or motor damage, you may need to repair or replace these parts.
How To Fix A Pool Pump That Is Not Priming (LOSING PRESSURE/SUCTION)
Step-by-Step Tips to Fix and Prevent Pressure Loss
- Check and Replace the Vacuum Hose
- Inspect the entire hose for splits, holes, or weak segments by submerging it and looking for bubbles or loss of suction.
- Replace damaged hoses; minor holes can sometimes be patched, but replacement is best for reliability.
- Purge All Air from the Hose
- Fully submerge the hose before connecting, or (more efficiently) hold the hose end over a return jet to force air out until only water flows through.
- Ensure Proper Water Level
- Keep the pool water above the middle of the skimmer opening to avoid sucking air into the system.
- Examine Pump and Filter Components
- Open the pump lid, inspect, clean, and lubricate all gaskets and O-rings with silicone lubricant.
- Check skimmer and pump baskets for debris and clean regularly.
- Inspect for Clogs
- Disconnect the hose and check for visible obstructions. Use a garden hose to flush out any debris trapped inside.
- Check for Collapsing Hose
- Watch the hose as the vacuum runs. If it pinches closed, replace it with a reinforced vacuum hose3.
- Balance Suction Lines
- If you have multiple skimmers or suction lines, adjust valves so you’re not concentrating all flow through a single point, which can overstress the system and hoses.
- Backwash or Clean Your Filter Regularly
- Dirty filters can restrict flow, especially with the added resistance of vacuuming.
Key Warnings
- Avoid letting undissolved shock or debris enter the vacuum hose—this can plug the line and further reduce suction.
- Check immediately for surface pool leaks if you notice water loss in conjunction with pressure drops.
- Run your pump only with proper water level and never with visible air rushing through the pump basket, as this can damage the pump seal.
Troubleshooting Summary Table
| Problem | Solution |
|---|---|
| Hose leaks/holes | Replace hose, patch minor holes |
| Air not purged from hose | Submerge/prime hose before connecting |
| Low pool water level | Top up pool before vacuuming |
| Loose gaskets, failing O-rings | Inspect, lubricate, and replace as needed |
| Clogged baskets/impellers | Remove debris, clean skimmer/pump/impeller |
| Collapsing hose | Replace with reinforced vacuum hose |
| Filter dirty/clogged | Backwash or clean filter |
Conclusion
Losing pump pressure when vacuuming almost always points to a suction-side air leak (damaged hose or loose gasket), air left in the vacuum hose, clogs, or occasionally a system not designed for the extra load of vacuuming. Careful inspection, hose replacement, good water level maintenance, and proper priming before each use typically solve the problem. Regularly maintaining your equipment will ensure strong vacuuming performance and a clean, healthy pool all season long.
If pressure loss persists even after these steps, consult a pool technician for a more thorough suction-side leak detection or system check.
FAQs For Pool Pump Losing Pressure When Vacuuming
Q: Why Does My Pool Pump Lose Pressure When Vacuuming?
A: the most likely cause is a clogged or dirty filter. Check and clean or replace if necessary before vacuuming.
Q: Can A Leaky Hose Cause Pressure Loss During Vacuuming?
A: yes, a leak or crack in the hose can cause air to enter, reducing pressure. Check for leaks or replace the hose.
Q: How Often Should I Backwash My Pool Filter?
A: backwash your pool filter when the pressure gauge rises 8-10 psi above normal or every six weeks, whichever comes first.
Q: How Do I Know If My Pump Motor Is The Cause Of Pressure Loss?
A: check for unusual noises, frequent overheating, and low pressure. If these are present, your pump motor may need to be repaired.
Conclusion
A pool pump losing pressure while vacuuming can be a frustrating issue for any pool owner. It is often caused by a clogged or damaged skimmer basket, debris in the suction lines, or a faulty pool pump. Regular maintenance and cleaning of the pool and its components can help prevent this problem from occurring.
In case the issue persists, it is recommended to seek the help of a professional pool technician to diagnose and fix the problem. Proper care and attention to a pool’s maintenance can help ensure a clear and enjoyable swimming experience.