Pentair Clean & Clear Plus Filter Guide: Cleaning, Maintenance, and Troubleshooting

The Pentair Clean and Clear Plus is a high-capacity cartridge filter available in four sizes (240, 320, 420, and 520 square feet). Cartridge filters require no backwashing — instead, cartridges are removed and hosed down when pressure rises. This guide covers when and how to clean the filter, how to safely open and close it, acid soaking, cartridge replacement, air relief valve maintenance, and troubleshooting.

Filter Overview

The Clean and Clear Plus is a large-area cartridge filter designed for high debris capacity. It operates at a maximum working pressure of 50 psi and requires no backwash valve — the filter lid is removed to access the cartridges for manual cleaning. The pressure gauge is the primary indicator of filter condition.

Record the original starting pressure when the system is first commissioned. Clean the cartridges when pressure reads approximately 10 psi higher than this original starting pressure, or when a significant reduction in flow is noticed. For variable speed pumps, record both the original starting pressure and the pump RPM at the time of recording — the clean threshold is 10 psi above whatever the starting pressure reads at that specific RPM.

Opening the Filter Safely

Required tools: 7/8-inch socket wrench (socket extender may be needed).

1. Turn the pump OFF and shut off any automatic controls (timers, automation). Disconnect power at the circuit breaker.
2. Open the Manual Air Relief Valve: turn the top of the valve 1/4 turn counterclockwise until it snaps into the full open position.
3. Stand clear of the filter and wait until all pressure is relieved. The pressure gauge must read zero (0) psi before proceeding.
4. Open the drain plug at the bottom of the filter and allow all water to drain from the tank.
5. Using a 7/8-inch socket wrench, loosen the clamp barrel nut. Allow the spring coils to fully decompress.
6. Remove the barrel nut, spring, and two washers from the T-bolt. Place them aside.
7. Remove the clamp ring from the filter and place it aside.
8. Carefully lift the filter lid away from the tank. Do not lift the lid by the air relief valve — this can damage the valve. If the lid is tightly sealed, wiggle it gently side to side to break the seal. Do not use a screwdriver or pry bar.
9. Place the lid and the O-ring in a safe location where they will not be damaged.

Installing the Filter Lid and Clamp Ring

Required tools: 7/8-inch socket wrench, rubber mallet.

1. Ensure the tank O-ring is clean and properly seated on the tank bottom flange.
2. Seat the filter lid onto the tank bottom so the O-ring is captured between the two halves.
3. Hold the ends of the clamp ring apart and place the clamp over both upper and lower tank flanges. Bring the ends together.
4. Insert the T-bolt through the clamp ends. Place the small washer onto the T-bolt, then the spring, large washer, and barrel nut. Hand tighten.
5. Using a 7/8-inch socket wrench, tighten further.
6. Tap around the entire outside of the clamp with a rubber mallet — multiple times around the full circumference — to seat it properly.
7. Continue tightening until the spring coils are touching.
8. Tap around the full clamp again and verify the spring coils remain touching. If not, continue tightening.
9. Close the drain plug at the bottom of the filter.

Monthly check: Inspect the spring coils at least once a month to ensure proper tension. If the coils do not touch, shut off the pump, relieve pressure, and tighten the nut until coils touch, then restart.

Start-Up After Service

1. Verify the spring coils are fully compressed (touching).
2. Open the Manual Air Relief Valve (1/4 turn counterclockwise until it snaps open).
3. Stand clear of the filter, then start the pump.
4. Watch for proper operation. The system is not working correctly if:
   • The pressure gauge indicates pressure before water outflow appears
   • A solid stream of water does not appear within 30 seconds after the pump basket fills
   • Water leaks from where the two halves of the filter meet
   If any of these conditions exist, shut off the pump immediately, open the air relief valve to relieve pressure, and clean the air relief valve. If the problem persists, call Pentair Technical Service at (800) 831-7133.
5. After a steady stream of water appears from the air relief valve, close the valve (1/4 turn clockwise).

Cleaning the Filter Cartridges

1. Follow the Opening the Filter procedure above.
2. Remove the pump strainer basket and clean it. Reinstall and secure the lid.
3. Remove the Compression Spring and Spring Adapter from the Top Manifold.
4. Remove the Top Manifold from the cartridges and set it aside.
5. Carefully remove each cartridge one at a time.
6. Using a garden hose with a straight-flow nozzle, hold the nozzle at a 45-degree angle to the cartridge and wash from top to bottom. Pay close attention to the area between pleats.
7. For pools with high levels of perspiration, suntan lotion, or other oils, soak the cartridges for at least one hour in one of the following:
   • A commercial filter cleaner (follow manufacturer instructions)
   • 1 cup trisodium phosphate (TSP) dissolved in 5 gallons of water
   • 1 cup dishwasher detergent dissolved in 5 gallons of water
   Thoroughly rinse each cartridge after soaking. Failure to remove oils before acid soaking will permanently restrict water flow and cause premature cartridge failure.
8. Wash out the inside of the filter tank and bottom manifold through the open drain plug.
9. Inspect the gasket around the outer lip of the bottom plate — it must be firmly and evenly seated.
10. Reinstall the bottom manifold, cartridges, and top manifold. Ensure the spring and standpipe assembly are retained on the top manifold.
11. Ensure the O-ring is clean and seat it onto the tank bottom.
12. Follow the Installing the Filter Lid and Clamp Ring and Start-Up procedures above.

Acid Soaking the Filter Cartridges

After extended operation, cartridges may develop mineral deposits (algae, calcium carbonate, iron) that restrict flow and cannot be removed by hosing alone. Acid soaking removes these deposits.

Required equipment: large plastic container, garden hose with straight-flow nozzle, muriatic acid (stored in opaque container), rubber gloves, safety glasses, N-95 dust mask.

1. Remove all oils and cleaning solutions from the cartridges before acid soaking. Skipping this step will cause permanent cartridge damage.
2. Put on all protective equipment.
3. In a large plastic container, prepare a solution of 1 part muriatic acid to 20 parts water. Introduce acid as close to the water surface as possible to minimize splash.
4. Gently place the bottom halves of the cartridges into the acid solution. Soak for 10 minutes, or until bubbling stops.
5. Turn the cartridges over and place the top halves into the solution. Soak for another 10 minutes, or until bubbling stops.
6. Remove the cartridges and thoroughly wash with a garden hose, top to bottom at 45 degrees.
7. Reinstall cartridges and dispose of the acid solution according to local regulations.

Replacing Filter Cartridges

Average cartridge life is approximately three years under normal conditions. Replace cartridges when cleaning no longer restores acceptable pressure readings.

1. Follow the Opening the Filter procedure above.
2. Remove the Compression Spring and Spring Adapter from the Top Manifold.
3. Remove the top manifold and set it aside.
4. Remove each cartridge. Inspect the gasket around the outer lip of the bottom plate — it must be seated evenly.
5. Install new cartridges on the bottom manifold. Reinstall the top manifold with the spring and standpipe assembly retained.
6. Follow the Installing the Filter Lid and Clamp Ring and Start-Up procedures above.

Maintaining the Pressure Gauge

The pressure gauge (P/N 190058) is the primary indicator of filter condition. Replace the gauge if it does not meet all of the following:

• Reads zero (0) psi after pressure is relieved and the system is off
• Indicates pressure when the system is operating
• Is readable and not physically damaged

Cleaning the Manual Air Relief Valve

1. Shut off the pump, shut off automatic controls, and disconnect power at the circuit breaker.
2. Open the air relief valve (1/4 turn CCW). Stand clear and wait until pressure gauge reads zero.
3. With the valve still installed on the filter, pull out the locking tabs and unlock the valve stem and cover assembly by turning counterclockwise and lifting.
4. Remove the valve stem and cover assembly from the valve body.
5. Clean debris from the valve stem and body. Insert a 5/16-inch drill bit through the valve body to ensure the air passage is clear.
6. Check that the O-rings are in good condition, properly positioned, and lubricated with a PTFE or silicone-based lubricant. Do not use petroleum-based products on O-rings.
7. Reinstall the valve stem and cover by pressing downward and turning clockwise until it snaps into position.

Troubleshooting

Replacement Part Numbers