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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 507 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: 16 left in stock
Fulfilled by Spreetail
Arrives Friday, Nov 22
Order within 17 hours and 32 minutes
Available payment plans shown during checkout

Size: 400,000 BTU (W3H400FDN)


Features

  • "Totally Managed" Flow saving energy by reducing pump run time
  • Silicon Nitride Ignition System
  • Cupro-Nickel Heat Exchanger ensures compatibility with almost all pool systems including salt pools
  • Low NOx certification
  • 83-84% industry-leading thermal efficiency

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: Friday, Nov 22

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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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
    • 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
    • unit quit and asurion 2 year warranty is worthless they charged me but don't cover this
Size: 150,000 BTU (W3H150FDN)
Hayward has no one to help in my area with a warranty as its brand-new gives code BD...so now i will request a credit on my so called worthless warr. and pay for the repairs as can't get any help from Hayward with the problem. crazy cuz i'm in Florida and pools are common here and the hayward locator gave me one dealer and they said sorry can't help with a gas heater ... show more
Reviewed in the United States on September 26, 2023 by Don C
    • The Hayward Natural Gas unit is NO# 1
Size: 150,000 BTU (W3H150FDN)
I purchased the 150,000 BTU natural gas unit on sale in late May. I installed the unit with my friend that is a licensed NYS electrician. The install was quite easy. I actually fired it up in minutes once we completed the installation. My pool holds 20,000 gals of water, the actual water Temperature at start up was 74 degrees. I ran the pool pump & Heater from 11:30 PM To 6:00 AM. In the 7 hours time the pool Temperature Rose from 74 degrees to 92 degrees, that is a rise of 18 degrees in 7 hrs. The ambient outside Temperature was 63 degrees, I did NOT use my solar pool cover for this test. This LITTLE hayward heater is a DYNOMO. For the past 7 years I had a 110k electric heat pump and it to 5 days to reach the above temperatures. I purchased it on Amazon for $4195 Biggest WASTE OF MONEY in the north east. I made the switch for the above reasons and MOST OF ALL MY ELECTRIC BILL was $810 a MONTH with that Stupid heat pump. I even called my electric company and spoke to the Director of Engineering which is my equivalent and he agreed heat pumps are NOT as economical as alot of the so called experts say. Lastly the Hayward 150k BTU heater is a FIVE STAR in my professional opinion. ... show more
Reviewed in the United States on July 13, 2023 by eddie macina
    • 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
    • Just what I was looking for
Size: 400,000 BTU (W3H400FDN)
Delivery was good and install was fairly easy. Make sure the gas company gets the manual and reads it for the size correct line. Unfortunately, ours had to redo it but they fixed it with no problem. Since things got delayed and it is warm now, we started it but have not actually heated to pool. I dont know why but it is much larger than I was expecting. The box was even larger. ... show more
Reviewed in the United States on June 13, 2024 by tgeorge

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