The store will not work correctly when cookies are disabled.

JavaScript seems to be disabled in your browser. For the best experience on our site, be sure to turn on Javascript in your browser.

If a product is unavailable online, please contact your local branch.

Search

Default welcome msg!

Sign In
Request Access

Products
- Pumps
- Filters
- Heaters
- Sanitization
- Automation
- Water Features
- Lighting
- Cleaners
- White Goods
- Parts & Accessories
- Hayward Products
  
  A broad selection, assuring you will have the perfect product for your backyard.
  
  Take a Look
Why Hayward
- Explore Products
  
  Better Pumps
  
  Better Filters
  
  Better Heaters
  
  Better Sanitisation
  
  Better Automation
  
  Better Water Features
  
  Better Cleaners
  
  Learn About Hayward
  
  At Hayward, we're more than just equipment.
  
  Learn more
- Hayward Insights
  
  Hayward Insights
  
  Hayward Insights provides expert advice, tips, and industry updates to help pool owners and enthusiasts with their swimming pool experience.
  
  Gain insight
Support
- Support Center
- Resources
  
  Hayward Firmware Updates
  
  Warranty
  
  Warranty Claims
  
  Product Registration
  
  Literature SKU Search
  
  Energy Calculator
  
  Support Center
  
  Hayward products including, quick reference guides,
  troubleshooting steps, and product support videos.
  
  Find out more
Company
- About Us
- Careers
- Investor Relations
- Hayward Rewards
  
  Join our 2023 Loyalty Program and earn reward points for each eligible purchase.
  
  Learn More
IMG Support
- IMG Home
- About IMG
- Newsplash
- Resources
  
  Warranty Claim Test
  
  Dealer Application
  
  Product Feedback
  
  Heater Size Calculator
  
  Contact Us
  
  Learn About Hayward IMG
  
  At Hayward IMG, we're more than just equipment.
  
  Learn more

Default welcome msg!

Sign In
Request Access

Hayward Sites

Partner Portal
Hayward Rewards
Flow Control
Paramount

Home
Products

Products banner

Products

Filters

Filtering by:

Series Heaters:
Universal H-Series Low NOx
Universal H-Series Low NOx
Heating Capacity (BTU/hr):
400,000
400,000

Filter By

Residential (1 item)
Heaters (1 item)

Gas (1 item)
Not selected: Gas

In Ground (1 item)
Not selected: In Ground

Universal H-Series Low NOx (1 item)
Selected: Universal H-Series Low NOx

150,000 (1 item)
Not selected: 150,000
250,000 (1 item)
Not selected: 250,000
400,000 (1 item)
Selected: 400,000

Natural Gas (NA) (1 item)
Not selected: Natural Gas (NA)

No (1 item)
Not selected: No

2" x 2-1/2" Union (1 item)
Not selected: 2" x 2-1/2" Union

Yes (1 item)
Not selected: Yes

Compare Products

You have no items to compare.

1Item

Download Assets Download Assets

Download Product Information and Images

1 Item

Sort By

Set Descending Direction

1 Item

You have no items to compare.

asset download

Universal H-Series Natural Gas 400,000 BTU Low NOx

SKU: H400FDN

1 Item

1 Item

Export type selection

Plunge into our newsletter

Sign up and be the first to hear about exclusives, promotions and more!

Enter your email address

Support & Resources

Support Center
FAQs
Site Help
Site Map
Contact Us
Energy Calculator
Heat Pump Calculator(opens in a new tab)

Company

Careers
Investors Relations
About Us
News

Inspiration

Hayward Insights

Copyright © 2025 Hayward Industries, Inc.

Terms & Conditions (opens in new tab)(opens in a new tab) Privacy Policy (opens in new tab)(opens in a new tab) Purchase Order Terms (opens in new tab)(opens in a new tab) Terms & Conditions of Sale (opens in new tab)(opens in a new tab)

earth

Americas

United States

English Español

Canada

English Français

Latin America

Europe

United Kingdom

France

Germany

Spain / Portugal

Italy

Oceania

Australia

New Zealand

Other Regions

Asia

Africa

Middle East