Air trapped inside a pool filter can reduce circulation, cause noisy operation, and prevent the pump from priming properly. More importantly, air inside a closed, pressurized system can become compressed. Compressed air stores energy and can raise the internal pressure beyond the system’s normal operating limits, creating a potentially dangerous situation.
Bleeding the air removes trapped pockets, restores proper water flow, and helps keep the system operating safely within its designed pressure range. This should be done anytime the system has been opened, the pump has lost prime, or after routine maintenance.
When You Should Bleed the Filter
- After cleaning or servicing the filter
- After opening the system following winterization
- If the pump loses prime
- If you see bubbles returning to the pool
Safety First
Before starting:
- Keep hands, hair, and loose clothing away from moving parts
- Never stand directly over the filter while starting the system
- Do not attempt this if the filter is damaged or cracked
Step-by-Step Instructions
1. Turn Off the Pump
Stop the pool pump. Never open the filter or air relief while the pump is running.
2. Locate the Air Relief Valve
The air relief valve is usually found:
- On top of the filter tank
- Near the pressure gauge
You will see a small knob, lever, or screw-type valve. Most modern filters have a manual air relief valve. The picture below shows the most common ones.
3. Open the Air Relief Valve
Slowly turn, lift or un-screw the valve to the open position.
You may hear air. This is normal.
Leave the valve fully open.
4. Start the Pump
Turn the pump back on while keeping the air relief valve open.
As the pump runs:
- Air will escape first
- Water will begin to sputter
- A steady stream of water will eventually flow
5. Close the Air Relief Valve
Once water flows smoothly and continuously (no air or spurting):
- Close the air relief valve securely
- Do not overtighten
The air has now been removed. Check there are no water leaks.
Take a moment to:
- Check around the valve and filter for any water leaks
- Confirm the pump is running smoothly
The pump may be left running or turned off.
If you have any questions or need expert advice