Air trapped in your pool’s return lines is a common yet frustrating problem that many pool owners face. When air infiltrates your filtration system and circulates through the plumbing, it can lead to poor water circulation, noisy pumps, reduced efficiency, and even costly damage over time. But with the right knowledge and techniques, you can safely and effectively remove air from your pool return lines and restore optimal performance to your pool system.
In this detailed guide, we’ll walk you through everything you need to know about identifying the source of air in your pool lines, the tools required, and the step-by-step process for removing that air. We’ll also explore common causes of air leaks and offer tips for preventing them in the future. Whether you’re a seasoned pool owner or new to the world of pool maintenance, this guide will provide the insights you need to keep your system running smoothly.
Understanding Pool Return Lines and How Air Affects Them
Before we dive into the process of removing air from your return lines, it’s important to understand how your pool’s plumbing system works and the role return lines play in circulation.
What Are Pool Return Lines?
Pool return lines are responsible for sending filtered water back into your pool. After the water passes through the pump and filter, it travels through the return lines and exits via return jets, which are strategically placed to promote even water circulation and distribution of pool chemicals.
These lines are under pressure, which is why air entering them can cause noticeable issues such as turbulent water flow, air bubbles, or even damage to your pump.
Why Air in Return Lines is a Problem
When air accumulates in pool return lines, it can cause several undesirable effects:
- Reduced Water Circulation: Air pockets disrupt the smooth flow of water, decreasing the system’s efficiency.
- Noisy Pump Operation: Air passing through the pump can cause loud gurgling or popping noises.
- Decreased Filtration Efficiency: Less water flow through the filter means dirt and contaminants remain in the pool longer.
- Potential Damage to Equipment: Excess air can cause cavitation in the pump, leading to wear and potential overheating.
So, tackling air in return lines not only improves your pool’s cleanliness, but also prolongs the life of your equipment.
Identifying the Source of Air in Your Pool Return Lines
Before you can get rid of air in your pool return lines, you need to understand where it’s coming from. Here are the most common sources:
Skimmer and Pump Area
These are the most common places for air to enter your system. The skimmer sits above water level and can draw in air if the water level drops too low or if the lid or O-ring is compromised. The pump lid may also allow air in if the seal is cracked or improperly seated.
Plumbing Leaks
Check all visible plumbing connections for leaks or cracks, particularly where they connect to the pump, filter, and heater. Even a small crack or loose fitting can allow air to enter the system when the pump is running.
Valves and Seals
Multiport valves, gate valves, or winterizing plugs that aren’t sealed properly can allow air into the system, especially after seasonal start-ups or maintenance work.
Bottom Drain Issues
A broken seal or crack in the main drain line can also allow air into the system. These are less common but harder to identify because they’re located under the pool water.
Tools and Materials Needed to Bleed Air from Pool Return Lines
Before beginning this process, gather the following tools and materials:
- A standard pool filter rated for your pool size
- A wrench set or appropriate tools for your system
- A screwdriver (flat or Phillips, depending on your filter system)
- A garden hose (for topping off water, if needed)
- Water testing kit (to check chemical balance post-bleeding)
- Replacement O-rings and seals (if necessary)
Make sure your power to the pump is shut off before handling any plumbing or equipment.
Step-by-Step Guide to Removing Air from Pool Return Lines
Follow these careful, sequential steps to safely and effectively eliminate air trapped in your pool return lines.
Step 1: Turn Off the Pool Pump
Before making any adjustments or attempting to bleed the system, disconnect the power to your pool pump to ensure safety and prevent possible damage.
Step 2: Check and Fix the Water Level
One of the simplest causes of air being pulled into the system is a low water level. Water should be at least halfway up the skimmer opening. If water levels are low, top it off using a garden hose before proceeding.
Step 3: Bleed the Pump
This step involves manually releasing air from the pump, allowing it to fill with water.
To bleed the pump:
- Remove the pump lid or pump basket cover by loosening the clamp or unscrewing it.
- You will likely hear or see air escaping and water dripping out.
- Reinsert the pump lid gently, but leave it slightly loose for now.
- Turn the pump power back on and let it run while holding the lid in place.
- As water fills the pump, air will rise and escape around the lid.
- Once water flows consistently without bubbles, tighten the lid securely.
This will often solve the problem of air in the return lines.
Step 4: Operate the Filter to Eliminate Remaining Air
Even after bleeding the pump, some air may remain trapped in the filter. Use the filter air bleeder valve.
- Locate the air bleeder valve on the top of your filter tank. It may be a small valve or part of a pressure gauge assembly.
- While the pump is running, open the air bleeder valve slowly.
- You’ll hear air escaping and see water misting out. Once a steady stream of water emerges, shut the valve tightly.
For sand or cartridge filters without a dedicated air vent, run the filter for several minutes on “filter” mode to allow any air to migrate to the top and escape naturally through circulation.
Step 5: Inspect Return Jets for Bubbles
Once the system is running smoothly with all valves closed, go to the return jets and observe the water flow.
Look for:
- Strong, consistent water flow with minimal turbulence
- No large air bubbles or excessive bubbling
If bubbles continue to erupt from return jets, air is still trapped somewhere.
Step 6: Use the Multiport Valve for More Intense Air Release (DE and Sand Filters)
For systems with a multiport filter valve, you can use the backwash or rinse cycle to assist in clearing trapped air.
Steps for multiport valves:
- Turn off the pump.
- Switch the valve to “backwash” and restart the pump for 30–60 seconds. This reverses flow and may help dislodge air pockets.
- Return the valve to “rinse” mode briefly (about 10 seconds), then back to “filter.”
Doing this can help circulate the water more forcefully to eliminate stubborn air pockets.
Step 7: Conduct Water Flow Test
If steps 1–6 don’t fully eliminate the air bubbles, perform a test to confirm flow rates and potential leaks.
- Turn off the pump again and visually inspect all visible plumbing and pump connections.
- Look for hairline cracks, loose fittings, or signs of wear.
- Tighten fittings or replace seals as necessary.
This is a good opportunity to inspect the O-rings on the pump, multiport valve, and filter tank. These should be inspected and replaced every season for optimal performance.
Common Mistakes to Avoid When Bleeding Air from Return Lines
Even if you follow each step carefully, certain missteps can compromise your air-bleeding efforts or result in more serious issues.
Over-Tightening Equipment
While it’s important to have secure connections, over-tightening pump lids, filter valves, or plumbing can damage threads or compress O-rings improperly. This can actually contribute to further air infiltration. Always follow manufacturer guidelines for torque and snugness.
Leaving the Pump Dry
Never run the pump for extended periods when it’s not fully primed with water. Doing so can damage the impeller and motor seal, leading to overheating or pump failure.
Ignoring Pressure Gauge Readings
Regularly check your pressure gauge (on sand and DE filters). If the pressure is abnormally low or fluctuating, this may indicate that air is still compromising the system.
Assuming Air Problems Correct Themselves
Air in the return lines will not simply disappear. Failing to address it promptly may result in long-term inefficiencies, chemical imbalances, and even visible algae growth due to poor circulation.
Preventing Air Leaks in the Future
Once you’ve successfully removed air from your pool’s return lines, take steps to reduce the chances of recurrence.
Maintain Appropriate Water Levels
As mentioned earlier, one of the primary entry points of air is through the skimmer when the pool water level drops too low. Ensure the water level is consistently above the midpoint of the skimmer opening, especially during filtration hours.
Regular Inspection and Maintenance
Schedule regular inspections of your pool pump, filter, plumbing, and valves. Look for signs of wear, aging O-rings, rust, or small leaks.
Some maintenance tips include:
- Inspect O-rings quarterly and apply lubricant to prevent drying
- Check skimmer lid and basket seals monthly
- Clean or backwash filters according to manufacturer instructions
Use Quality Seals and Hardware
Invest in high-quality pump and filter gaskets and O-rings. Avoid using generic or off-brand seals that may dry out or crack sooner than expected.
Seasonal Pool Start-Up Best Practices
At the beginning of every swimming season, don’t just turn the pump on and walk away. Manually check for leaks, prime the pump, and bleed air from lines during start-up after winterizing.
When to Call a Professional
If you’ve gone through all the steps above and still see air escaping through your return jets, there may be a deeper issue with your system, such as:
- Leak in underground plumbing
- Failed pump impeller
- Severe seal failure in main drain
In these cases, it’s wise to contact an experienced pool technician. They may use a pressure test or dye test to find hidden leaks or recommend repair services for more extensive plumbing damage.
Conclusion
Eliminating air from your pool’s return lines doesn’t have to be a daunting task. With a bit of patience, attention to detail, and a clear understanding of the system, you can restore clean water flow and ensure your pool equipment runs efficiently all season long.
However, understanding the problem is just as important as fixing it. Knowing how to identify air entry sources, properly maintain your system, and prevent future issues will keep both your pool and its owner stress-free.
By following this guide, you’re not just solving an immediate problem—you’re investing in long-term pool health and performance. So the next time you notice air bubbles flowing from your return jets, you’ll be ready to handle it like a pro.
Key Takeaways
- Air in return lines affects system performance and equipment longevity.
- Common causes include low water levels, leaks around skimmers, and poor seals.
- Bleeding the pump and filter regularly removes trapped air.
- Regular maintenance helps prevent recurring air problems.
- If air persists, consult a professional to check for hidden leaks.
Stay proactive, stay informed, and enjoy a cleaner, quieter, and better-performing pool system all year.
What are pool return lines and why is air trapped in them a problem?
Pool return lines are the pipes that carry filtered water back to the pool from the pump and filtration system. These lines are essential in maintaining water circulation, which is vital for keeping the pool clean and chemically balanced. However, when air becomes trapped in these lines, it can disrupt water flow, create noise, and potentially cause damage to the pump or other components of the system.
Air trapped in pool return lines can lead to several issues, including reduced circulation efficiency and uneven chemical distribution. This often causes the pump to work harder, increasing wear and tear on the equipment. In some cases, excessive air in the system can cause the pump to lose its prime, stopping water flow entirely. Understanding how to properly remove air from return lines helps ensure optimal performance and extends the lifespan of your pool equipment.
What are the common signs that air is trapped in pool return lines?
One of the most noticeable signs of trapped air in pool return lines is gurgling or popping noises coming from the return jets or the pump itself. You might also observe bubbles coming out of the return lines into the pool, especially right after the pump has been turned on following a period of inactivity. The water pressure in the lines might also seem inconsistent or weaker than usual.
Another indicator is a drop in water flow or poor filtration, which can cause the pool water to appear cloudy or unclean. The pump may also show signs of strain, such as motor overheating or vibration. If left unaddressed, these symptoms could lead to bigger mechanical issues or a shortened life for your pump. Recognizing these early signs is a crucial part of troubleshooting and maintaining your pool system.
How can I manually bleed air from my pool return lines?
To manually bleed air from your pool return lines, start by locating the pressure-side air bleeder valve on your filtration system. If your system has one, open it by turning the valve counterclockwise. As air escapes, you should see bubbles emerging from the valve until water begins to flow steadily. Once water starts to leak out, close the valve to prevent water loss and ensure proper pressure buildup.
If your system does not have an automatic or manual air bleeder valve, you can try slightly loosening the union on the return line to allow trapped air to escape. Be cautious with this method to avoid dislodging the connection completely or causing leaks. This process is typically done with the pump running so that the water flow can help flush the air out. Manually bleeding the lines is a simple but effective technique that can restore smooth operation to your pool system.
Is there a way to reset the pool pump to remove air from return lines?
Yes, resetting the pool pump can help in releasing air trapped within the return lines. Begin by turning off the pump at the circuit breaker to ensure safety. Remove the pump lid and check the pump basket for debris or excessive water. If the basket is dry, it likely means air is trapped in the system.
Add water to the pump basket until it is completely full, then securely replace the lid. Turn the pump back on and allow it to operate for a few minutes. This resets the prime and helps push air through the system and out the return lines. Keep an eye on the pressure gauge; if it rises to the normal operating range, you’ve successfully removed the air. This method is especially useful after performing maintenance or when the water level in the pool has dropped significantly.
How can I prevent air from getting trapped in pool return lines in the first place?
Preventing air from becoming trapped in return lines involves regular maintenance and vigilance. Ensure that all connections and fittings on the return lines are tight and leak-free. A small leak on the suction side of the pump can allow air to enter the system, which can then end up trapped in return lines or the pump housing.
Maintain an appropriate water level in your pool, especially during periods of heavy use or evaporation. If the water level is too low, the skimmer can suck in air, introducing it into the system. Use a high-quality filter that isn’t restricting flow and backwash it regularly to avoid pressure imbalances. Ensuring that the pump is properly primed before startup also limits the air introduced into the system and can prevent ongoing issues.
What tools or materials are needed to effectively get air out of pool return lines?
To effectively remove air from pool return lines, you’ll generally need minimal tools, but a few basics are essential. A screwdriver or adjustable wrench may be needed to loosen unions or valves. A garden hose can be useful for adding water to the pump basket or rinsing off debris in the filter or skimmer. If your system has an air bleeder valve, ensure that it’s functioning correctly and not clogged with debris or calcium buildup.
You might also want to have Teflon tape or pipe sealant on hand to ensure tight, air-free connections when resealing any fittings. Additionally, a pressure gauge can help monitor performance and indicate if the system is operating normally after air has been removed. These tools, when used properly, can save time and prevent future air entrapment issues, making pool maintenance more efficient and effective.
When should I consult a professional about air in my pool return lines?
If you’ve tried all common methods of removing air from your pool return lines and are still experiencing issues, it may be time to consult a professional. Persistent air problems could signal a more serious issue, such as a hidden leak, damaged pump seal, or a crack in the plumbing that’s allowing air into the system. These issues require expert diagnosis and often involve expensive or invasive repairs if left unchecked.
Additionally, if you’re unfamiliar with the components of your pool system or feel uncomfortable performing maintenance yourself, a licensed pool technician can assist. Professionals have advanced tools, such as pressure testing equipment, and can ensure that your system is fully sealed and operating as it should be. Scheduling regular inspections can also help catch problems early, saving you money and extending the health of your pool over time.