Part # W3H250FDN
Warranty 1-Year Parts-Only Warranty
Hayward® W3H250FDN Universal H-Series Low NOx Pool & Spa Heater – 250,000 BTU, Natural Gas
Now with Cupro Nickel Heat Exchanger for Enhanced Durability in Saltwater Pools
The Hayward® W3H250FDN is a 250,000 BTU natural gas pool and spa heater engineered for exceptional performance, energy efficiency, and installation flexibility. With low NOx emissions, it's ideal for environmentally conscious pool owners and meets air quality standards in low-emission regions. Its advanced Cupro Nickel heat exchanger ensures longevity, especially in salt-chlorinated or aggressive water chemistry environments.
Key Features:
BTU Rating: 250,000 BTU/hr
Fuel Type: Natural Gas
Cupro Nickel Heat Exchanger: Provides superior corrosion resistance for salt pools and high flow systems
Low NOx Certified: Meets California and Texas air quality emission standards
Forced Draft System: Delivers consistent heating performance in all weather conditions
Easy Installation: Right or left-side plumbing, gas, and electrical connection options
Polymer Header: Reduces erosion, extends heater life, and improves hydraulic performance
Digital LED Control Panel: Displays temperature, diagnostics, and settings for easy operation
Compatible Plumbing: 2" x 2.5" CPVC union connections
� Specifications:
Model: W3H250FDN
Fuel: Natural Gas
BTU Input: 250,000
Ignition Type: Electronic
Water Connection: 2" x 2.5" CPVC unions
Dimensions: 32.6" L x 30.6" W x 24.0" H
Weight: Approx. 140 lbs
Warranty: 1-Year Parts-Only (Limited)
Applications:
In-ground residential pools
Pool and spa combos
Saltwater systems
Pools requiring quick heat-up and precise temperature control
✅ Why Choose the Hayward W3H250FDN?
Ideal size for medium to large pools
Fast recovery and efficient operation
Built to withstand harsh pool environments
Trusted performance backed by Hayward
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Overall Dimensions
How do you know if a pool heater is a propane heater or a natural gas heater?
Reply
Typically in the product name we use the abbreviation of "LP" for propane or "NG" for natural gas. Click here for a full listing of our >Pool Heaters.
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Will a gas heater operate at the low speed of a dual speed motor?
Reply
Probably not - Most gas heater will shut off at low GPM levels (20-40) to keep the heater cores from overheating - 20 for 200 BTUs, 40 for 400 BTUs. Depending on your pool system you might get these GPM levels at the low speed but generally these heaters must be run at the motor's high speed.
Reply
What is the difference between an Electronic and Millivolt ignition?
Reply
The basic answer is that Millivolt is the old style of ignition, using a standing pilot light. While the electronic ignition uses a spark start system like a gas grill. Electronic ignitions are more efficient in gas usage and also are better suited for high wind areas where a pilot light might get extinguished.
Reply
Is a vent required for typical outside installation for the Hayward 150k Ng Lo Nox heater?
Reply
For the Hayward Lo Nox heater, you would not need to purchase an additional vent if you are using it outside. If you are installing the heater outside, we recommend you purchasing a heater cover. This will protect your heater from debris, rain, snow, heat- or pretty much anything that could get caught in your heater. The Weather-Out Pool Heater Cover can be viewed on our website.
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2 to 4 hrs
Screwdriver, Pliers, Wrench Set
1 4
My previous heater was problematic for the last ten years. With that being said I opened the pool this year and tryied stating the heater and the exhaust fan was totally rotten. I decided to turn threats INYO like always and purchase a new one The purchase and the delivery was seemless as always
The Most Helpful Review
10 1
(4 out of 5 stars) Efficient, easy to use Pool Heater
Reviewed By: David B. from Boston, MA ()
The Hayward 250 BU Lo-Nox natural gas heater is efficient and works quite well. More efficient than our old Hayward microvolt 250 BTU heater. The only drawback so far is the pressure limiter switch on the heater requires a 1 HP pump to work properly.
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The Most Recent Reviews
(5 out of 5 stars) Good value
Reviewed By: Inyo Customer ()
Easy install. Works great
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1 0
(5 out of 5 stars) Fantastic
Reviewed By: Inyo Customer ()
Replaced a 2007 model h250 with new model. Many improvements to current model. Minor plumbing to place in same location. Inyo shipped quick attractive price. Free shipping.
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(5 out of 5 stars) Heater has been working fantastic
Reviewed By: Inyo Customer ()
Heater has been working fantastic
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(5 out of 5 stars) Hayward Heaters produce!
Reviewed By: Inyo Customer ()
I picked this heater due to the wind conditions here on Padre Island. It out performs the others in this environment, plus it pairs well with my Hayward pump. I did have to change the side of the inlet/outlet and it was simple and straight forward. The wiring was simple as well. No special consideration as I wired it 220/240 volt, but it is simple enough to wire 115 volt as well. This heater works as well or better than my last one which was a Raypak. I also like that it has the cupronickel heat exchanger standard! I would definitely recommend this heater. Hayward makes an excellent product.
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(4 out of 5 stars)
Reviewed By: Inyo Customer ()
works well and very easy to install.
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1 0
(5 out of 5 stars)
Reviewed By: Inyo Customer ()
Shipping was received as predicted, in excellent shape. order was extremely easy, no problems.
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6 1
(5 out of 5 stars) Fast, Silent, and easy to use pool heater
Reviewed By: BJS8863 from McHenry, IL ()
Pros: Compact, Fast, Sient, and easy to use
Cons: Heavy - the electric hookup needs a complete cover
We have gone through 3 pool heaters in 5 years. For the equivalent price, this Hayward (The only brand I will every buy in pool heaters) heats the water faster - 20 degrees in less than 48 hours, easy to start, and the flow monitor is great, and it doesn't sound like its going to rocket to the stars.
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