Hayward CX800C – Filter Head Assembly with Air-Relief

Product Overview

The Hayward CX800C is a factory-replacement filter head designed for the StarClear II™ cartridge filter series. It includes an integrated air-relief vent and offers a durable, precisely-engineered cover assembly to maintain optimal filtration performance.

Key Features

• Direct-replacement head assembly for compatible StarClear II™ C800 filter systems.
• Built-in air-relief vent allows trapped air to escape and supports proper filter priming.
• Robust thermoplastic construction for longevity in pool chemical environments.
• Molded mounting features designed for secure bolt-down and sealing with filter body.

Technical Specifications

• Part Number: CX800C
• Application: Head assembly (filter lid + air relief) for C800 cartridge filters.
• Weight: Approx. 3.2 lb.
• Material: Engineered plastic cover, pressure-rated for residential pool use.

Compatibility & Installation Notes

This filter head is designed for use with the Hayward StarClear II™ C800 cartridge filter tank. Before ordering, verify your existing filter model and ensure the bolt-hole pattern and vent placement match. Proper installation helps restore full filter performance and prevents air-lock or bypass issues.

Installation Instructions

• Turn off the pump, relieve any pressure in the system, and drain as needed before servicing the filter.
• Remove the old head assembly, clean the sealing flange on the filter tank, and inspect for damage or corrosion.
• Place the new CX800C head on the tank, align bolt holes, insert bolts, and tighten evenly in a star pattern to specified torque.
• Prime the pump, restore circulation, monitor pressure, and check for any leaks or presence of air in the filter housing.

Troubleshooting

• Air bubbles in the filter or pump basket: Ensure the air-relief vent is open and functioning, and check that the new head is sealed properly.
• Leak at head joint: Verify flange surface is clean, the gasket is properly installed, bolts are evenly torqued, and there is no damage to tank threads.
• Reduced flow or pressure drop: Confirm all ports are correctly aligned and the head was installed correctly; check cartridge condition and tank internals.

Maintenance Tip

Inspect the filter head, bolts, and sealing gasket during annual service. If the vent assembly shows wear or the head has cracks, replace immediately. A well-sealed head assembly prevents air-ingress and helps maintain efficient filtration. Replacing the head at first sign of damage helps avoid costly downtime or compromised water clarity.