Hayward Universal H Heater, LowNOx, CU-Ni Exch., 400K BTU, NG (H400FDN) (W3H400FDN)

W3H400FDN Universal H-Heater, 400K BTU, Natural Gas, LowNOx, Cupro-Nickel Exchanger and Salt Friendly. The Universal H-Series is an energy efficient, high performance, installation adaptable commitment to the pool service professional.

Brand Hayward


Heater Disclosure: *

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Hayward W3H400FDN is Natural Gas – The cupro-nickel heat exchanger places it above its competitors (Pentair, Jandy, Raypak) at similar prices. 84% Thermal Efficiency.

The new Hayward W3H400FDN Universal H-Series is a totally new gas heater design that combines industry leading hydraulic performance, environmentally responsible low-NOx emissions and superior reliability with the installation flexibility to easily adapt to new or existing pools and spas for what just might be the most perfect combination of features and benefits ever offered in an in-ground pool and spa heater.

Hayward’s W3H400FDN Universal H-Series gas heater adapts to each pool and spa owner’s needs to make life a little more flexible and convenient.

NOTE: The Hayward W3H400FDN Universal H-Series of heaters meet the NOx Emission standards set by the California South Coast Quality Air Management Commission for 2001 and the Texas Natural Resource Conservation Commission Code.

(This item is new in box)


Great Low Profile Appearance

Environmentally Responsible Low NOx Emissions

Patent Pending Polymer Header Design for Industry Leading Hydraulic Performance

Totally Managed Cupro Nickel Heat Exchanger Flow for Superior Reliability

2″ x 2 1/2″ CPVC Union Plumbing Fittings

The Right Connections for Easy Installation, Service and Use

Ultimate Installation Flexibility for New or Existing Equipment Pads

Independent Left or Right Side Electric, Water and Gas Connections

25% Lighter Weight Means Less Physical Effort to Install

Only Front Panel Access Required for Installation and Service

Easy Gas Valve Adjustment

Easy Dual Voltage Conversion with Fuse Protected Circuit Boards

Overall Dimensions 37″ width, 24″ height, 29.50″ depth 197lbs.

Shipping included with liftgate in the continental U.S.

Additional information
Weight 197.0 lbs

38.5" x 32" x 29.3"

Heater BTU

400K – 500K

Heater Exchange


Manufacturer Number



Universal H




1 Year Limited



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WARNING: Some products can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm.  For more information go please visit www.p65warnings.ca.gov