Pentair 20" Jumbo Radial Flow Carbon Water Filter Cartridge

Improve water quality while maintaining strong whole-house water flow with the Pentair 20" Jumbo Radial Flow Carbon Water Filter Cartridge, designed for high-capacity chlorine, taste and odour treatment.

The Pentair Pentek RFC20-BB uses a radial flow design that passes water through a bed of granular activated carbon (GAC) from the outside towards the centre of the cartridge. This provides high-capacity carbon treatment while maintaining a very low pressure drop.

A 70 micron porous polyethylene outer shell contains the carbon bed and significantly reduces the release of carbon fines into the filtered water.

With a manufacturer-stated chlorine reduction capacity of more than 378,541 litres at 15.2 L/min and an initial pressure drop of only 0.06 bar at 15.1 L/min, the RFC20-BB is particularly well suited to large homes, farms and high-demand point-of-entry filtration systems.

Pentair Pentek RFC20-BB

The Pentair Pentek RFC20-BB is a high-capacity granular activated carbon cartridge designed for compatible 20" Jumbo / Big Blue water filter housings.

Unlike conventional GAC cartridges that direct water lengthwise through the media, the RFC20-BB uses a radial flow configuration. Water enters through the porous outer shell and travels inward through the granular activated carbon before reaching the spun polypropylene core.

This construction provides chlorine, taste and odour treatment while maintaining a low pressure drop.

At 20" long, the RFC20-BB provides double the carbon bed volume of the 10" RFC-BB, delivering greater treatment capacity and longer service life between cartridge changes.

Why Choose This Water Filter Cartridge?

• Radial flow GAC design — water travels inward through the granular activated carbon bed.
• High-capacity carbon treatment — manufacturer-stated chlorine capacity of more than 378,541 litres at 15.2 L/min.
• Very low pressure drop — initial pressure drop of only 0.06 bar (0.90 psi) at 15.1 L/min.
• Chlorine reduction — activated carbon treats chlorine in the incoming water.
• Taste and odour improvement — helps improve common drinking-water taste and odour issues.
• Reduced carbon fines — 70 micron porous polyethylene outer shell helps contain the granular carbon media.
• 20" Jumbo format — provides double the carbon bed volume of the 10" RFC-BB.
• High-flow whole-house design — suited to point-of-entry and high-demand filtration applications.
• Large-home and farm applications — greater capacity reduces the frequency of cartridge replacement.
• Operating temperature of 4.4–51.7°C.
• NSF/ANSI 42 materials certification — certification applies to material requirements only.

How It Works

The Pentair Pentek RFC20-BB uses radial flow filtration.

Water first enters through the 70 micron porous polyethylene outer shell.

It then travels radially inward through the bed of granular activated carbon, where the carbon reduces chlorine and compounds responsible for unpleasant taste and odour.

The treated water then reaches the spun polypropylene core before exiting the cartridge.

The flow path can be represented as:

70 Micron Porous Polyethylene Outer Shell → Granular Activated Carbon → Spun Polypropylene Core

This radial flow design provides a large carbon-treatment area while keeping pressure drop low.

The larger 20" cartridge length provides double the carbon bed volume of the 10" RFC-BB, giving the RFC20-BB significantly greater chlorine treatment capacity.

Reduced Carbon Fines

Loose granular activated carbon cartridges can release fine carbon particles, known as carbon fines, into the filtered water.

The Pentair RFC20-BB uses a 70 micron porous polyethylene outer shell to contain the carbon bed and substantially reduce the release of these fines.

This allows the cartridge to retain the high-flow, low-pressure-drop characteristics of granular activated carbon while reducing the amount of loose carbon material passing downstream.

Best Suited For

The Pentair 20" Jumbo Radial Flow Carbon Water Filter Cartridge is well suited to:

• Whole-house water filtration
• Point-of-entry filtration
• High-flow carbon filtration
• High-demand residential systems
• Large homes
• Farms and rural properties
• Chlorine reduction
• Taste and odour treatment
• Mains-water filtration
• Residential drinking-water treatment
• 20" Jumbo filtration systems
• Big Blue filter housings
• Multi-stage water filtration systems
• Applications where low pressure drop is important
• Systems where longer cartridge life between replacements is desirable
• Disinfected tank or bore-water systems where carbon treatment is required

Where tank or bore water contains significant sediment, install an appropriate sediment pre-filter upstream.

Key Specifications

Radial Flow GAC vs Carbon Block

A radial flow GAC cartridge and a carbon block cartridge both use activated carbon, but their construction and flow characteristics are different.

The Pentair RFC20-BB uses loose granular activated carbon contained between its porous outer shell and inner core. Water travels radially inward through the carbon bed.

This construction provides high-flow carbon treatment with very low pressure drop, making it particularly useful on main water lines and whole-house systems.

A carbon block uses compressed carbon media and can combine carbon treatment with finer particulate filtration, depending on its micron rating.

Choose the RFC20-BB where high-capacity chlorine, taste and odour treatment with low pressure drop is the priority.

Chlorine Treatment Capacity

The Pentair Pentek RFC20-BB has a manufacturer-stated chlorine reduction capacity of:

More than 378,541 litres at 15.2 L/min

The larger 20" cartridge provides double the carbon bed volume of the 10" RFC-BB, resulting in significantly greater treatment capacity.

Actual cartridge life will depend on:

• Incoming chlorine concentration
• Water quality
• Daily water consumption
• Operating flow rate
• Sediment loading
• Other substances present in the incoming water

Replace the cartridge when chlorine taste or odour begins to return or carbon-treatment performance noticeably declines.

Flow & Pressure Drop

One of the key advantages of the Pentair RFC20-BB is its combination of high-capacity treatment and very low initial pressure drop.

At 15.1 L/min, the initial pressure drop is:

0.06 bar (0.90 psi)

The manufacturer-stated chlorine reduction capacity is more than 378,541 litres at 15.2 L/min.

This makes the cartridge particularly useful in whole-house applications where maintaining water pressure and flow is important.

Why Choose the 20" Over the 10" RFC-BB?

The 20" RFC20-BB provides double the carbon bed volume of the 10" RFC-BB.

The larger carbon bed delivers:

• Greater chlorine treatment capacity
• Longer service life between cartridge replacements
• Higher capacity at a given flow rate
• Better suitability for high-demand water systems
• Less frequent cartridge changing

For larger homes, farms and high-demand whole-house systems, the 20" RFC20-BB is the higher-capacity option.

Keep in mind that the 10" and 20" cartridges require their corresponding housing sizes and are not interchangeable.

NSF/ANSI 42 Certification

The Pentair RFC20-BB is NSF/ANSI Standard 42 certified for material requirements only.

This certification relates to the materials used in the cartridge that come into contact with drinking water.

It does not certify the stated chlorine reduction performance.

The chlorine reduction capacity of >378,541 litres at 15.2 L/min is manufacturer-stated.

Installation

The Pentair RFC20-BB is designed for use in a compatible 20" Jumbo / Big Blue water filter housing.

The cartridge measures 4.50" × 20" (114 × 508mm).

To replace the cartridge:

1. Turn off the water supply.
2. Release pressure from the filter housing.
3. Remove the filter housing sump.
4. Remove the existing cartridge.
5. Clean the inside of the housing if required.
6. Check that the housing O-ring is clean and seated correctly.
7. Insert the new Pentair RFC20-BB cartridge.
8. Reassemble the housing.
9. Slowly restore water pressure.
10. Check the housing carefully for leaks.
11. Flush the new carbon cartridge before normal use.

Maintenance

Carbon cartridge life depends on incoming water quality, chlorine concentration, water consumption and operating conditions.

The Pentair RFC20-BB has a manufacturer-stated chlorine reduction capacity of more than 378,541 litres at 15.2 L/min.

Replace the cartridge when:

• Chlorine taste begins to return
• Unpleasant odour returns
• Carbon-treatment performance noticeably declines
• Water flow becomes excessively restricted
• The cartridge reaches the end of its useful treatment capacity

Where incoming water contains significant sediment, installing an appropriate sediment filter upstream can help protect the carbon media.

What's Included

1 × Pentair Pentek RFC20-BB 20" Jumbo Radial Flow Carbon Water Filter Cartridge

Model: RFC20-BB
Part Number: 155247-43

Frequently Asked Questions

What does the Pentair RFC20-BB do?

The Pentair RFC20-BB uses granular activated carbon to reduce chlorine, unpleasant taste and odour.

Its radial flow construction provides high-capacity carbon treatment while maintaining a very low pressure drop.

What does GAC mean?

GAC stands for Granular Activated Carbon.

The activated carbon is present as loose granules rather than being compressed into a solid carbon block.

What is radial flow?

Instead of directing water lengthwise through the cartridge, the RFC20-BB directs water from the outside inward through the granular activated carbon bed.

This provides a large treatment area while helping maintain low pressure drop.

Does it reduce chlorine?

Yes. The RFC20-BB is designed for chlorine reduction.

Pentair states a chlorine reduction capacity of more than 378,541 litres at 15.2 L/min.

Does it improve taste and odour?

Yes. The granular activated carbon reduces chlorine and helps improve unpleasant taste and odour.

What are carbon fines?

Carbon fines are small carbon particles that can be released from loose granular activated carbon media.

The RFC20-BB uses a 70 micron porous polyethylene outer shell to contain the carbon bed and substantially reduce the release of carbon fines into the filtered water.

Is this a carbon block filter?

No. The RFC20-BB uses granular activated carbon (GAC) rather than compressed carbon block media.

What is the pressure drop?

The initial pressure drop is only 0.06 bar (0.90 psi) at 15.1 L/min.

This low pressure drop makes the cartridge well suited to high-flow point-of-entry and whole-house applications.

How much water can it treat?

Pentair states a chlorine reduction capacity of more than 378,541 litres at 15.2 L/min.

Actual service life depends on incoming water quality, chlorine concentration, water usage and operating conditions.

Why choose the 20" instead of the 10" RFC-BB?

The 20" RFC20-BB provides double the carbon bed volume of the 10" RFC-BB.

This gives it greater treatment capacity and longer service life between replacements, making it particularly suitable for large homes, farms and high-demand whole-house systems.

Does the 70 micron outer shell make this a 70 micron sediment filter?

The 70 micron specification refers to the porous polyethylene outer shell used to contain the carbon bed.

The supplied specifications do not describe the RFC20-BB as a dedicated 70 micron sediment cartridge.

Where significant sediment is present, use an appropriate sediment pre-filter upstream.

Can I use it on tank or bore water?

It can be used as a chlorine, taste and odour treatment stage on adequately disinfected water supplies.

Where tank or bore water contains sediment, pair the RFC20-BB with an appropriate sediment pre-filter.

Will it fit my 20" Jumbo housing?

The RFC20-BB is designed for compatible 20" Jumbo / Big Blue water filter housings.

The cartridge itself measures 4.50" × 20" (114 × 508mm).

Can I put this in a 10" Jumbo housing?

No. The RFC20-BB is a 20" cartridge and requires a compatible 20" Jumbo housing.

The 10" and 20" RFC-BB cartridges are not interchangeable between housing lengths.