Hayward W3H400FDN Pool Heater | Universal H Series - 400K BTU, Natural Gas, Low NOx
Hayward W3H400FDN Pool Heater | Universal H Series - 400K BTU, Natural Gas, Low NOx
Transform your pool into a year-round oasis with the Universal H-Series Natural Gas 400,000 BTU Low NOx Heater. Shasta Pool Supply markets the best prices on Hayward pool equipment. Specifically, the Hayward W3H400FDN Pool Heater combines energy efficiency and installation flexibility.
Hayward W3H400FDN Pool Heater
The Universal H-Series boasts a patented header by-pass design. Furthermore, it ensures uniform water flow through all tubes for faster and more efficient heating. Therefore, this innovative design significantly reduces pump run-time and results in substantial energy savings.


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Key Features
• Energy Efficient: Delivers 400,000 BTU/hr heating capacity with low NOx emissions
• Corrosion Resistant: Standard cupro nickel heat exchanger for excellent salt water and chemical resistance
• Installation Adaptable: 2in x 2 1/2in CPVC union plumbing connections for easy setup
• Low Environmental Impact: Meets clean air quality standards
• Powerful Performance: Heats pools up to 125 gallons per minute
Technical Specifications
Dimensions: 24" x 34" x 29.5"
Weight: 195 lb
Fuel Type: Natural Gas
Voltage: 120V
Circuit Amps: 5.5
Specs
- Part Number: W3H400FDN
- Manufacturer: Hayward
- Length: 24.0
- Width: 34.0
- Height: 24.0
- Voltage: 120/240

Adapts Easily to Larger Plumbing
Resistance to Salt Water and Pool Chemicals
Presently, this heater features a cupro nickel heat exchanger that provides superior resistance to salt water and pool chemicals. Moreover, the low NOx emissions meet strict air quality standards.
Installation is a breeze with the 2in x 2 1/2in CPVC union plumbing connections. Additionally, it adapts easily to larger plumbing for enhanced efficiency.
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What our customers are saying
I will only use Shasta.
I will only use Shasta.
Tory W.
We had to do pickup but it went smoothly
We had to do pickup but it went smoothly
Suzy I.
I bought a demo/open box chlorinator from them. So far the product has been working well (one week) and it looked new in the manufacturers box when I got it. Communication with them was great. Price I got for the open box item was worth it. Would use them again. Thanks.
I bought a demo/open box chlorinator from them. So far the product has been working well (one week) and it looked new in the manufacturers box when I got it. Communication with them was great. Price I got for the open box item was worth it. Would use them again. Thanks.
Ken J.
FAQ
Our expert staff answers customer's most asked questions.
How does the warranty differ for products purchased online?
Products purchased from an Authorized Pentair Online Reseller (with product codes beginning with EC-) receive a one-year parts-only warranty from the purchase date. Exceptions include IntelliChlor cells and IntelliFlo SVRS pumps, which receive a two-year parts-only warranty. These products are not eligible for the bundled three-year extended warranty.
How many BTUs does my heater need to heat a pool or spa?
The ideal BTU rating for your heater depends on your desired heating speed. A 200 BTU or 250 BTU heater is suitable for a spa or pool, while a 400 BTU heater will heat your pool and spa more rapidly.
My Pool water gets too hot in the summer to enjoy it. What can I cool it down with?
Many heat pumps now come with a option to cool the water. Click here to view our heat pumps with this option.
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