Hayward ProGrid DE Filter Air Problems: Air Relief, Air In Tank, and Suction Leaks

Understanding Air In A DE Filter System

Air in a DE filter system can occur in two distinct places: inside the filter tank itself (normal at startup, abnormal during operation), and in the suction plumbing (always abnormal). These have different causes and different fixes.

Air in the filter tank at startup

When the filter is drained for cleaning or winterization and then refilled, air is trapped in the upper filter body. This is expected. The manual air relief valve exists specifically to purge this air. Failing to purge it properly leaves an air pocket that compresses under pressure and gives inaccurate gauge readings.

Air in the filter during normal operation

If the filter accumulates air during normal operation — you can hear gurgling from the tank, or the pressure gauge swings erratically — air is being continuously introduced from the suction side of the system. This is a plumbing problem, not a filter problem.

The Manual Air Relief Valve: Operation And Service

Normal startup procedure

1. After reassembling the filter, ensure the MAR valve body is locked in the LOCK position in the upper filter body.
2. Place the MAR in the OPEN position before starting the pump.
3. Start the pump. Do not stand over or near the filter.
4. Air will discharge from the MAR valve, followed by a mix of air and water, followed eventually by a steady stream of water only.
5. Return to the filter to close the MAR valve only when a steady stream of water (not air or a mix of air and water) is discharging. This is the explicit Hayward instruction — do not close the valve prematurely.

MAR valve lock/unlock mechanism

The MAR valve twists into a LOCK position (clockwise) and an UNLOCK position (counterclockwise). When the indicator on the MAR flange aligns with LOCK on the upper body, the valve is secure in the body. When aligned with UNLOCK, the MAR can be lifted straight out (a slight rocking motion helps).

Servicing the MAR valve

If the MAR valve drips or leaks at the upper body, the O-ring kit (DEX2420Z8A — set of 2 O-rings) is the likely fix. Replacement procedure (tech-level only):

1. Turn off all system pumps and electrical power.
2. Close all system valves to prevent water from flowing to the filter.
3. Place the MAR in OPEN position.
4. Wait until all water discharge has stopped.
5. Grasp the MAR body at the flats and turn counterclockwise until the indicator aligns with UNLOCK.
6. Pull straight up to remove the MAR. A slight rocking motion helps.
7. Inspect the O-rings and replace with the DEX2420Z8A kit if cracked or deformed.
8. Wipe the MAR O-ring groove in the upper body clean.
9. Align the notch in the MAR flange with the notch on the upper filter body. Press straight down.
10. Turn clockwise until the indicator aligns with LOCK. Verify the MAR discharge points away from electrical connections.

If the MAR valve body itself is cracked or the internal CCX1000V assembly is damaged, replace the full DEX2420MAR2 assembly or the CCX1000V component.

Diagnosing Suction-Side Air Leaks

The clearest sign of a suction-side air leak is small bubbles returning to the pool from the return jets during normal pump operation. Air is being pulled into the suction side of the pump and carried through the filter into the returns.

Step 1: Check pool water level

Owner-level: The water level should be at least halfway up the skimmer opening. If the water level is below the skimmer mouth, the skimmer is drawing air. Add water to the pool.

Step 2: Inspect the pump strainer lid and O-ring

The pump strainer lid is a very common air leak source. Check the O-ring on the lid for cracks, compression set, or debris. Replace if deformed. Hand-tighten the lid evenly — do not use tools on the strainer lid if it is plastic.

Step 3: Check suction plumbing unions

Union O-rings on suction plumbing are another common air entry point. Dry the union area, run the pump briefly, and watch for bubbles or a drip. Replace union O-rings if leaking.

Step 4: Check for air at the pump volute or shaft seal

Air bubbles in the strainer basket (visible through the clear lid) that do not clear after a few minutes point to a suction leak between the basket and the impeller. This could be the pump lid O-ring (again), the diffuser, or the shaft seal.

Step 5: Check the valve on the suction line

A suction valve that is only partially open, or a diverter valve that is allowing air to enter from a dry skimmer line, can cause intermittent air in the system. Verify all suction valves are fully open and that any unused suction lines are properly plugged.