Hayward GMX600NM Valve Clamp Assembly for Pro-Series Top-Mount Sand Filters

The Hayward GMX600NM is the OEM 2-piece valve clamp assembly used to secure a top-mount multiport valve to the filter tank on select Hayward Pro-Series sand filters. If your existing clamp is cracked, warped, stripped, or won’t tighten evenly, replacing the clamp helps restore a tight, stable valve-to-tank connection and can help prevent leaks caused by poor clamp tension.

Fits / Compatibility

• Hayward Pro Series top-mount sand filters including common models such as S166T, S180T, S210T, S230T, and S244T
• Also commonly used on additional Hayward top-mount sand filter families that use this clamp style (verify your filter model and clamp style)
• Frequently paired with Hayward Vari-Flo XL top-mount valves that clamp to the tank (for example, valve assemblies that list GMX600NM as the included clamp)

What It Does

• Clamps the multiport valve securely to the filter tank flange
• Provides even clamping force so the tank O-ring can seal properly
• Helps prevent valve shifting, seepage, and clamp failure from cracked or fatigued plastic

What’s Included

• (2) Black Noryl clamp halves (GM600-NM is commonly molded into each half)
• (2) Bolts (commonly ~2-1/8" length)
• (2) Nuts
• (2) Rubber end caps (bolt caps)

Note: This clamp secures the valve to the tank. The tank O-ring that seals between the valve and tank is typically a separate part (often referenced as GMX600F on many setups). If you have a leak at the valve-to-tank seam, consider replacing the O-ring at the same time.

Common Reasons to Replace

• Clamp is cracked, split, or sun-brittle
• Clamp won’t tighten evenly or won’t hold tension
• Valve shifts or rocks on the tank flange
• Leak at the valve-to-tank connection due to poor clamping (after confirming the tank O-ring is in good shape)

Installation Notes

• Turn off the pump and relieve filter pressure before loosening any clamp hardware.
• Clean the tank flange and valve mating surfaces so the clamp seats flat and evenly.
• Tighten the clamp hardware evenly to avoid cocking the valve or pinching the O-ring.
• After reassembly, run the system and check carefully for seepage around the clamp seam.

Related Products

• Hayward GMX600NM Valve Clamp (search)
• Hayward GMX600F Tank O-Ring (search)
• Hayward SP071620T Vari-Flo XL Top-Mount Valve (search)
• Hayward Pro Series Sand Filter Parts (search)
• Silicone O-Ring & Gasket Lubricant (search)

Maintenance Tips

• Keep the clamp area clean—grit on the flange or O-ring can cause leaks and uneven clamp tension.
• Do not overtighten to “stop” a leak; replace the tank O-ring if it’s flattened, stretched, or nicked.
• If the valve-to-tank joint seeps after service, depressurize, re-seat the valve evenly, and retighten the clamp uniformly.
• Shade exposed equipment when possible—direct sun accelerates plastic aging.