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Navien PeakFlowE anti-scale system for NPE Series condensing water heaters and NCB-E combi-boilers

  • Scale inhibitor
  • Free-installer Inlet Ball Value
  • Chemical-free and environment-friendly
  • Increases flow rates

This is a highly recommended environmentally-friendly accessory that treats hard water issues to address the water quality going into your Navien unit(s). A “must buy” in areas of hard water. Scale build-up from hard water is the biggest single reason for unit failures.

PeakFlowE prevents scale by converting dissolved hardness minerals into powerless particles that will not attach themselves onto any of the Navien heating elements. PeakFlowE, or other similar scale inhibitors, when sized correctly for the installation, will help to insure the longevity of your Navien equipment and eliminate hard water quality problems.

Maximum pressure
90 psi/62 bar
Maximum temperature
Minimum temperature
Inlet/outlet connections
3/4" FNPT
Service flow rate
up to 6 gpm (23 lpm)
Gallon rating (continuous flow rate)
up to 4 gpm, 24/7/364 for 2 years for each media cartridge
Media cartridge does not have a grain removal capacity. However, other contaminants present in the water will gradually degrade the effectiveness of this cartridge. Change the PeakFlowE cartridge (#GXXX001726) at least once every two years.
Unit weight
15 lbs/6.8 kg
6.5 to 8.5
Hardness (maximum)
75 grains (1282 ppm CaCO3)
40°F to 100°F (5°C to 38°C)
<2 ppm
Iron (maximum)
0.3 mg/l
Manganese (maximum)
0.05 mg/l
Oil & H25
none allowed
none allowed
Silica (maximum)
20 ppm* - PeakFlowE media does not reduce silica scaling. While silica tends to have a less significant effect on scale formation than other minerals, it can act as a binder that makes water spots and scale residue outside the plumbing system difficult to remove.
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