Air volume control valves on well water systems regulate how much air stays in your pressure tank, and adjusting them depends on whether you have a shallow well or deep well setup. Shallow well systems typically need no adjustment at all, while deep well air release valves have a screw that changes back pressure in roughly 5 PSI increments per quarter turn. Getting this setting right prevents two common problems: a waterlogged tank that makes your pump short-cycle, or too much air blowing out of your faucets.
How Air Volume Control Valves Work
Your pressure tank needs a cushion of air above the water to maintain steady pressure throughout your house. Without enough air, the tank fills completely with water (called waterlogging), and your pump kicks on and off rapidly every time you open a faucet. Too much air, and you get bursts of air sputtering from your taps.
The air volume control valve sits on or near the pressure tank and manages this balance. In deep well systems, a bleeder valve installed in the drop pipe (typically 10 to 20 feet down the well) works together with a snifter valve to replenish air with each pump cycle. When the pump stops, water drains back to the bleeder port, and the snifter valve opens to let air into the pipe. When the pump restarts, that trapped air gets pushed into the tank. The air release valve on top then vents excess air so the tank doesn’t become air-bound.
Shallow Well Systems: Simple Fixes
If you have a shallow well with an air volume control like the Johnson Controls F92 series, there’s no adjustment screw to turn. These valves are designed to operate without oiling or adjustment. If your pump starts short-cycling after several days of use, the tank doesn’t have enough air. The fix is to open the air inlet valve on the pump itself so more air enters the system. That’s the entire adjustment for most shallow well setups.
Deep Well Systems: Adjusting the Air Release Valve
Deep well air volume controls have a back pressure adjustment screw that determines how much air the tank retains. These valves come factory set at approximately 25 PSI (give or take 10%), which works for most installations. You can adjust the release pressure anywhere from 0 to 40 PSI, though going above 40 PSI is possible but not recommended.
Increasing Air in the Tank
If your pump short-cycles and the tank feels waterlogged (heavy and full when you tap on it), you need the tank to hold more air. Turn the adjustment screw to the right (clockwise) to increase back pressure. This traps more air in the tank even when the float is holding the valve open, giving you greater drawdown capacity, meaning more usable gallons of water between pump cycles.
Reducing Air in the Tank
If air is blowing out of your faucets, the back pressure is set too high and the tank is retaining too much air. Turn the adjustment screw to the left (counterclockwise) to decrease venting pressure. Watch your pressure gauge while the system vents. The gauge reading tells you exactly what the back pressure is set to.
How Much to Turn the Screw
The adjustment is more sensitive than most people expect. A quarter turn changes the setting by approximately 5 PSI. For finer adjustments, every 10 degrees of rotation changes back pressure by about 1.1 PSI. Make small changes, let the system run through a few pump cycles, and check the results before adjusting further.
Know Your Pressure Switch Settings First
Before adjusting anything, check your pressure switch settings. The two most common configurations are 30/50 PSI and 40/60 PSI. The first number is the cut-on pressure (when the pump starts), and the second is the cut-off pressure (when it stops). On a non-bladder tank, the air pre-charge should be 2 PSI below the cut-on pressure. For a 30/50 system, that means 28 PSI. For a 40/60 system, 38 PSI.
These numbers matter because your air volume control adjustment needs to work within the range your pressure switch defines. If you’re adjusting the air release valve’s back pressure to, say, 30 PSI on a system with a 30/50 switch, you’re venting air right at the point the pump kicks on, which may not leave enough air cushion.
Signs Your Valve Needs Attention
A few symptoms point directly to air volume control problems rather than other parts of the system:
- Rapid pump cycling: The pump turns on and off every few seconds or minutes when water is running. This usually means the tank is waterlogged because the valve is releasing too much air, or the bleeder and snifter system isn’t replenishing air properly.
- Air sputtering from faucets: Bursts of air mixed with water at your taps mean the tank has too much air. The back pressure on the air release valve is set too high.
- Tank feels uniformly heavy: Knock on the tank from top to bottom. A properly charged tank sounds hollow near the top (where the air cushion is) and solid lower down. If it sounds solid everywhere, it’s waterlogged.
- Valve stuck or not venting: Internal components can wear out over time. If the float or valve seat is corroded, no amount of screw adjustment will fix it, and the valve needs replacement.
Checking the Bleeder and Snifter Valves
On deep well systems, the air volume control valve is only one piece of the air management system. If your adjustments to the air release valve don’t solve the problem, the issue may be upstream. The snifter valve (at the wellhead) lets air into the pipe when the pump shuts off. If it’s stuck closed, no new air enters the system and the tank gradually waterlogs regardless of your air release setting.
The bleeder valve down in the well allows water to drain back so the snifter can do its job. If the bleeder is clogged or the check valve above it is leaking, water drains back into the well continuously and the air replenishment cycle breaks down. Both valves close automatically under pump pressure, so they shouldn’t leak while the pump runs. If you see water escaping from the snifter while the pump is on, its internal valve has failed.
When troubleshooting, start with the easiest check: the air release adjustment screw. If a quarter turn in either direction doesn’t improve things after a few pump cycles, inspect the snifter and bleeder next. These small valves are inexpensive but are the most common failure points in the whole air management chain.