Top 10 Tankless Water Heater Filter System – Replacement Under-Sink Water Filters

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1. 3M Aqua-Pure

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3M Aqua-Pure Whole House Scale Inhibition Inline Water System AP430SS, Helps Prevent Scale Build Up On Hot Water Heaters and Boilers

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3M Aqua-Pure #ad - Nsf standard 42 certified: tested by nsF International to NSF/ANSI Std; 42 for material and structural requirements only. High flow rates: 3/4 inch npt inlet/outlet connections for easy installation and high flow rates rated for up to 10 GPM; System to be installed on cold water line feeding the water heater.

Maintains efficiency: By inhibiting scale build up on heating elements, helps maintain water heater efficiency. Helps protect hot water heaters: polyphosphates, help to inhibit scale build up in hot water heaters both standard gas or electric and tank less styles and boilers; Helps extend the life of hot water heaters and hot water using appliances, included in this product, pipes, and downstream plumbing fixtures such as faucets and shower heads.

Corrosion resistance: 304 stainless steel head can be installed on existing copper pipes in the home; It consists of a corrosion resistant material that provides long service life. Easy to replace: easy change out of the 3M Aqua-Pure AP431 Replacement Water Cartridge makes system maintenance easier. Ideal for any size home. Product specifications: system has a pressure range of 25 to 125 PSI 862 kPa and operating temperature of 40 to 100F 4. 4 to 37. 8c.
Brand3M Aqua-Pure #ad
Manufacturer3M #ad
Height10.2 Inches
Length2.8 Inches
Weight2.3 Pounds
Width2.8 Inches
Part NumberAP430SS
Model70020003060

2. KleenWater

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Polyphosphate Filter for Scale Prevention, Tankless Water Heater Filter, KleenWater KW2520SCALEX-3 Tankless Hot Water Filter System

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KleenWater #ad - Polyphosphate filter to prevent scale and reduce the harmful effects of water hardness. Protects tankless and traditional tank hot water systems and helps avoid costly service calls. Compatible with all brands such as rinnai, atmor, takagi, Noritz, ECOTEMP, Bosch, Rheem, Eemax, Ecosmart, Navien and Marey Power. Kleenwater transparent water filter housing, 3 water filter cartridges 2. 5 x 20 inch, bracket and wrench. Can be installed at the "point of entry" to provide scale and corrosion protection for the entire household.
BrandKleenWater #ad
ManufacturerKleenWater #ad
Part NumberKW2520SCALEX
ModelKW2520SCALEX

3. KleenWater

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KleenWater KW2520SCALEX Tankless Hot Water Filter System, Tankless Water Heater Filter, Polyphosphate Filter for Scale Prevention

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KleenWater #ad - Polyphosphate filter to prevent scale and reduce the harmful effects of water hardness. Can be installed at the "point of entry" to provide scale and corrosion protection for the entire household. Protects tankless and traditional tank hot water systems and helps avoid costly service calls. Compatible with all brands such as rinnai, atmor, Rheem, takagi, Noritz, Bosch, Eemax, ECOTEMP, Ecosmart, Navien and Marey Power. Kleenwater transparent water filter housing, water filter cartridge 2. 5 x 20 inch, bracket and wrench.
BrandKleenWater #ad
ManufacturerKleenWater #ad
Part NumberKW2520SCALEX
ModelKW2520SCALEX

4. Fette Filter

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Water Filter Cartridge Compatible with Aqua-Pure AP431 Hot Water Scale Inhibitor for AP430SS Pack of 3, Fette Filter

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Fette Filter #ad - Interchangeable with 3m aqua-pure ap430, AP430SS & SF18-S Scale Inhibition System. Contains - 3 premium water filter Cartridges that prevent limescale and corrosion from building up that will prevent corrosion and blockage of your pipelines.

Quality - it's recommended that you should replace the inhibitor every 6 months for the most effective scale inhibition this will vary based on water conditions of your home. Flow rate is up to 10 gpm so it meet's water demand for your entire home. With its precise design it delivers a perfect fir for no water leakage. Guaranteed satisfaction or your money back - we have made a complete commitment in making you happy with your purchase.

No questions! No small letters! But, in a rare case if you aren’t "5-stARS HAPPY" simply let us know and enjoy 100% cash back. Excellent premium - this filter material can protect and extend the service life of your home water appliances like heaters, dishwashers, and other systems. Compatible models - fits for 3m aqua-pure ap431, hf8-s, kleenwater kw431.
BrandFette Filter #ad
ManufacturerFette Filter #ad

5. Premiere Sales Water

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Tankless Water Heater Filter System with Scale Inhibitor Water Filter Cartridge

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Premiere Sales Water #ad - Sturdier filter housing than others on the market—constructed with 15% more material! Grooved, 5 micron cartridge has more surface area for higher absorption. German siliphos ii scale control product is extremely effective & withstands stressful conditions. Nsf tested and certified sediment/scale inhibitor cartridge. Flow rate: 16 gallons per minute.
BrandPremiere Sales Water #ad
ManufacturerPremiere Sales Water #ad

6. WaterSentinel

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AP430, AP431, Compatible with AP430SS, Dish & Clothes Washer, WaterSentinel WSP04 Whole House Scale Inhibitor In-line Water Filter Replacement Cartridge for Conventional & Tankless Water Heater

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WaterSentinel #ad - Rates: rated up to 10gpm gallons per Minute water flow. Our scale inhibitor filters are manufactured using the best available materials with unparalleled attention to quality.

Increase efficiency and water flow. Simple to use: Quick change-out, easy system maintenance. Compatibility: 3m aqua-pure ap431, kleenwater kw431. Quality: made in the usa, the wsp04 is designed to extend the life of hot and cold water systems, downstream plumbing fixtures and pipes by removing scale. Protection: slow regulated release of phosphate prevents limescale and corrosion protecting hot water heaters dish washers, irons, clothes washer, steamers. Operating pressure 30-125 PSI. Interchangeable with 3m aqua-pure ap430, HF8-S, AP430SS and SF18-S models.
BrandWaterSentinel #ad
ManufacturerWaterSentinel #ad
Height2.5 Inches
Length8 Inches
Weight1 Pounds
Width2.5 Inches
Part Number102719
ModelWSP04

7. Culligan

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Clear, Culligan WH-S200-C Whole-House Sediment Water Filtration System

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Culligan #ad - Bypass with shut off valve. Stainless steel reinforced inlet/outlet. Removable filter timer And integrated bracket design.
BrandCulligan #ad
ManufacturerCULLIGAN #ad
Height15.94 Inches
Length6.18 Inches
Width6.57 Inches
Part NumberWH-S200-C
ModelWH-S200-C

8. 3M Aqua-Pure

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3M Aqua-Pure Whole House Sanitary Quick Change Water Filter System AP903, Reduces Sediment, Chlorine Taste and Odor

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3M Aqua-Pure #ad - Nsf standard 42 certified: tested by one of the world’s most respected independent certification organizations that helps protect the world’s food, water, consumer product and environment. Clearly great water: This whole house water filter reduces sediment as well as chlorine taste and odor*.

Corrosion resistant: 304 stainless steel head can be installed on existing copper pipes in the home It consists of a corrosion resistant material that provides long service life. 100, 000 gallon capacity: replacement cartridge has an activated carbon filter with nominal heavy duty particulate reduction rating of 5 microns and a 100, 000 gallon capacity at high flow rates of 10 gpm and even at intermittent peak flow rates of 20 gpm**. Easy to replace: sanitary quick change sqc design allows for fast and easy change-outs of the 3M Aqua-Pure AP917HD Replacement Water Filter Cartridge without having to contact the filter media or the need for a filter wrench.

Ideal for larger homes and is effective with both chlorinated municipal and non-chlorinated well water systems. Flow rate: 1” inlet and outlet connections to help a plumbing professional with easy installation and peak flow rates up to 20 gpm to meet the water pressure demands of most homes.
Brand3M Aqua-Pure #ad
Manufacturer3M #ad
Height27 Inches
Length6 Inches
Weight9.8 Pounds
Width6 Inches
Part NumberAP903
Model5621102
Warranty25 year warranty

9. DuPont

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DuPont WFPF13003B Universal Whole House 15,000-Gallon Water Filtration System

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DuPont #ad - Features universal 500 Series Poly Block Cartridge. Standard system has 3/4 in. Inlets and outlets. 3-year limited Warranty. Filters up to 15, 000-gallon For Home or Office. Improves clarity and taste of Incoming Water, Also Protects At The Kitchen Tap.
BrandDuPont #ad
ManufacturerDTP Vendor A3RBLNEOZFTF6F #ad
Height0 Inches
Length0 Inches
Weight0 Pounds
Width0 Inches
Part NumberWFPF13003B
ModelWFPF13003B
WarrantyThree-Year Limited Warranty

10. 3M Aqua-Pure

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3M Aqua-Pure Whole House Sanitary Quick Change Water Filter System AP904, Reduces Sediment, and Scale, Chlorine Taste and Odor

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3M Aqua-Pure #ad - Flow rate: 1” inlet and outlet connections to help a plumbing professional with easy installation and peak flow rates up to 20 gpm to meet the water pressure demands of most homes. Easy to replace: sanitary quick change sqc design allows for fast and easy change-outs of the 3M Aqua-Pure AP917HD-S Replacement Water Filter Cartridge without having to contact the filter media or the need for a filter wrench.

Ideal for larger homes and is effective with both chlorinated municipal and non-chlorinated well water systems. Fitting type: NPT Female. It consists of a corrosion resistant material that provides long service life. 100, 000 gallon capacity: replacement cartridge has an activated carbon filter with nominal heavy duty particulate reduction rating of 5 micronss and a 100, 000 gallon capacity at high flow rates of 10 gpm and even at intermittent peak flow rates of 20 gpm.

Corrosion resistant: 304 stainless steel head can be installed on existing copper pipes in the home. Clearly great water: this whole house water filter reduces sediment build-up, chlorine taste and odor as well as scale – helping to increase the life of hot water heaters and appliances dishwashers, clothes washers,  etc. Nsf standard 42 certified: tested by one of the world’s most respected independent certification organizations that helps protect the world’s food, water, consumer product and environment.
Brand3M Aqua-Pure #ad
Manufacturer3M #ad
Height4.5 Inches
Length25.2 Inches
Weight10.35 Pounds
Width4.5 Inches
Part Number5621104
Model5621104