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Hayward

Hayward W3H400FDN Universal H-Series 400,000 BTU Natural Gas Pool and Spa Heater for In-Ground Pools and Spas

    • Based on 508 reviews
Condition: New
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This item's return window has been extended for the holiday season: Returnable until Jan 31, 2025

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Availability: Only 8 left in stock, order soon!
Fulfilled by Spreetail
Arrives Dec 22 – Dec 27
Order within 5 hours and 57 minutes
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Size: 400,000 BTU (W3H400FDN)


Features

  • The Hayward Universal H-Series 400,000 BTU Natural Gas Heater delivers premium heating performance for years of reliable, long-lasting comfort
  • A durable cupro nickel heat exchanger offers exceptional protection against corrosion and premature failure caused by unbalanced water chemistry
  • Industry-leading hydraulic design reduces circulation pump run time to provide major energy savings
  • Front-panel-only access and intuitive control pad provide easy operation, service and maintenance
  • Low NOx emissions meet air quality standards in all low-NOx areas, ensuring low environmental impact

Description

The Universal H-Series 400,000 BTU Natural Gas Pool & Spa Heater from Hayward provides reliable, long-lasting comfort for pools and spas with a surface area up to 1,200 ft. Built with a durable cupro nickel heat exchanger, it offers exceptional protection against corrosion and premature failure caused by unbalanced water chemistry, ensuring you get season after season of premium heating performance. The Universal H-Series boasts industry-leading hydraulic performance coupled with lightning-fast speed-to-heat capability—so you spend less time waiting, and more time swimming. Its low NOx emissions meet air quality standards in all low-NOx areas, so you can rest easy knowing its environmental impact is low, too.

Product Dimensions: 39.6 x 32.8 x 30.6 inches


Item Weight: 195 pounds


Manufacturer: Hayward


Item model number: W3H400FDN


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Dec 22 – Dec 27

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Nice heater for the money
Size: 250,000 BTU (W3H250FDN)
Review Image by wkmgator wkmgator
Review Image by wkmgator wkmgator
Review Image by wkmgator wkmgator
We recently installed this heater to go with our Core 35 which is $1,400.00 itself to convert to a pool salt system. Usually our pool is cloudy but since going to salt it’s cleared up considerably. We decided to install a heater after talking about doing so for years now as the pool is almost always cloudy during the summer and Generally we can only swim May - September due to the water getting to chili in October- April. We are hoping with this heater to extend our swimming season to 11 months out of the year. It took roughly 4 days to install it So it was a little hard to hook up we had to run gas lines literally all over the side of our house and through our attic and underground to get to our heater as you can see from the pictures. We tested it out the first night and overnight it warmed our pool from 65* to 80*F, Def can feel the warm water coming out of the jets. Looking forward to trying this out more in October and November when temperatures really drop down but so far I’m pleased with it. Spent roughly $1,200.00 in labor to get the work done and another $800 in parts, like gas line pipes, fittings plumbing and valves… thankfully lowes was able to cut and put the fittings on our gas lines for us but I would say this is a minimum $4,500.00 project undertaking perhaps a bit more if using a pool company, professional plumber or if you live in a big city. We got the 250,000 btu heater and our pool is roughly 22,500 gallons which maybe overkill but wanted to go to big rather than to small on a nice heater…Just wanted to throw that out there for anyone considering getting one installed. That price includes the cost of the unit. The unit really isn’t loud. Update we have had it a little over a week now and we love it! We are in the pool almost daily now. I generally keep the heater on 78* degrees and when I get off work and home around 530pm I’ll cracked it up to 104* and by 7:30pm it’s over 94*! Talking about nice and relaxing I could literally sit in the pool as if it were a hot tub! Updated after a month we are in October now and still like the heater. Gas bill was about $60 more than it normally is for this time of the year and we generally keep the heater on 82F in the pool. One issue we have had is the heater will show the code LO every now and then and will go into a protection mode and will not work until you backwash and let the pressure out ... show more
Reviewed in the United States on September 16, 2022 by wkmgator wkmgator
    • Great heater
Size: 200,000 BTU (W3H200FDN)
Easy to Install and works great heating the pool. Installation was a breeze. Started up first time and heats up our 30ft round pool a couple degrees per hour. Great replacement for my old Hayward Millivolt heater that lasted 20 years.
Reviewed in the United States on May 27, 2024 by Jeffrey Lawlor
    • DON'T BUY!!! Hayward Pool Heater, 250,000 BTU (W3H250FDN), Tan
Size: 250,000 BTU (W3H250FDN)
Do not buy this product the company Hayward will not stand behind their product... we are on our 2nd pool heater, and they have both tore up!!! The last one I purchased was this past summer and it has started leaking water.. the company says they will not replace or fix the part because it is chemical damage... WHAT THE HELL!! it's made for a pool that has Chemicals in it!!! We had a Hayward sponsored repairman come out and he told my husband it is a factory defect, and we are not the only people who has had this to happen to their NEW UNIT!!!! I am beyond frustrated!!! So if you have any common sense don't purchase this piece of JUNK! ... show more
Reviewed in the United States on October 17, 2024 by kathy cochran
    • Great
Size: 250,000 BTU (W3H250FDN)
Very easy to install and use, highly reccomend. We do keep it covered during the winter months
Reviewed in the United States on November 22, 2024 by SL
    • Do not buy from this company. They do not honor their warranty.
Size: 150,000 BTU (W3H150FDN)
Unit had an AO reading as soon as it was installed, faulty blower switch . Hayward ‘s warranty techs were booked 2-3 months out. This company did not step in to help, they tried to pass bill onto Delivery company . I ended up paying my own tech 250.00 to repair brand new unit instead of 150 to uninstall to return and 350 more to put in new unit. Unethical sellers , no help from Amazon here either. Buy elsewhere!!!!!!! Update. The company ended up, reimbursing me for the labor. ... show more
Reviewed in the United States on March 17, 2023 by Nancy Jafari
    • Best Heater I have Owned
Size: 400,000 BTU (W3H400FDN)
So I purchased nearly identical model 17 years ago. Self installed except for need of larger supply line for gas input that required a licensed plumber. While I did have a couple failures related to the odd geckos crawling up behind a circuit board with 220 voltage (part easily obtained from Amazon and replaced myself) and shorting out. The heater performed wonderfully! Fast forward to this spring and it was not working after winter months. No input from control board. Tested things I was sure of to no avail. BUT then realized this was 17 years old! I purchased this newer version and it arrived. Unwired and unplumbed from old and connections identical to new. Rewired and replumbed in about 45 minutes and it was up and running 100%. Highly Recommend Hayward products. I also use there pool pumps and sand filters among other odds and ends. Always satisfied! ... show more
Reviewed in the United States on September 1, 2023 by Douglas Pilcher
    • Compact and efficient.
Size: 250,000 BTU (W3H250FDN)
I have a small in ground fiberglass pool. Heats the pool quickly. My pool company installed it.
Reviewed in the United States on August 27, 2024 by Mitch
    • Excellent heater
Size: 400,000 BTU (W3H400FDN)
Heater works great had a 200,000 Hayward prior to this and a 20,000 gallon inground pool the 200,000 struggled to keep up and eventually stopped working so I decided to go big with the 400 great move because it pretty much slipped right into the same fittings that the 200 had the only thing I had to change was my gas and that was minimal Had it up and running in a couple hours and heated the pool 20° overnight. The shipping was excellent R & L carriers delivered it. It showed up without a mark on it. It was a few days late, so I was mad about that but other than being a few days late I definitely go back to that company again they did a great job shipping it ... show more
Reviewed in the United States on August 20, 2023 by jim

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