The small valve near a pool filter’s pressure gauge is easy to overlook. It is not a shortcut for fixing high pressure, and it is not permission to loosen the tank lid. Its purpose is to release air under the operating and service procedures specified for that particular filter.
For Chino homeowners, the useful first step is identifying the filter model and recognizing when something has changed—not experimenting with unfamiliar valves.
What does the air relief valve do?
Air can enter a filtration system during service. Pentair’s Clean & Clear guide explains that the manual air relief valve releases trapped air during the specified restart procedure. It also warns that pressurized air can force a filter lid off, causing severe injury or death. That is why shutdown, pressure relief, assembly and restart instructions belong together; turning one small handle is not a complete safety procedure. Read the Clean & Clear guide.
Do not confuse three different parts
The pressure gauge displays a reading. The manual air relief valve provides a controlled outlet specified by the manufacturer. A multiport valve, where fitted, routes water between operating modes. They are not interchangeable controls. See our separate guide to pool multiport valve settings for that distinction.
A zero gauge reading is not an all-clear
Never loosen a clamp, locking ring, lid or fitting to test whether pressure remains. A gauge must be working correctly, and the complete procedure for the exact filter must be followed. If you do not understand the equipment or cannot confirm its condition, leave it closed and arrange professional service. Pentair recommends professional filter maintenance in its filter safety center.
When should a professional inspect it?
Ask for an inspection if the valve or nearby assembly leaks, appears damaged, will not operate normally, or repeatedly needs attention. Do not force a stuck part or tighten a leaking assembly while the system is operating. Keep clear of the filter and follow the manufacturer’s safe shutdown guidance; if water is reaching electrical equipment, stay clear and get qualified help.
Describe what you observed without trying to reproduce the fault. Useful details include:
The filter brand, exact model and a photo of its label, taken from a safe position.
Whether the issue began after cleaning, another repair or an ordinary startup.
Where water appears and whether the gauge reading changed.
Any accompanying bubbles at the returns or unusual pump behavior.
Ask for the procedure for your equipment
Different filters and generations can use different hardware. A video showing a similar-looking tank is not enough to establish the right procedure. Ask your technician to identify the correct manual and explain what you should observe between visits.
Need help describing a filter concern? Send your equipment details through our service inquiry form. Include your Chino or nearby service address so we can review the request.
