Review – Hayward W3H400FDN / H400FDN H-Series Pool Heater

This review is focused on the Hayward W3H400FDN H-Series pool heater but since all the H-Series heaters are identical this review also applies to all of the other sizes in this series like the W3H250FDN (250k BTU) and the W3H200FDN (200K BTU). The W3H400FDN replaces the older model H400FDN. If you buy a pool heater online make sure you have it installed by a certified Hayward technician to keep your warranty valid. If you install it yourself you will void the warranty.

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Hayward W3H400FDN Review

Note : The Hayward W3H400FDP is the propane equivalent of the W3H400FDN.

There’s a lot of useful information in this article to help you choose the right heater for your pool, spa or hot tub — and I’ve included some videos that show you how to install and troubleshoot your Hayward W3H400FDN .

I know that this will probably one of the most expensive things you’ll buy online but you’ll actually save a lot of money this way. If you buy it from your local pool dealer it will be far more expensive. Buying online will save you money in the long run.

First let me state that all of the features for the Hayward H400FDN are also true for the other H-Series pool heaters. The only differences are in the specifications like BTU, weight and size.

The Hayward W3H400FDN is a powerful 400,000 BTU natural gas pool heater that can raise the temperature of an 800 gallon pool by 30ºF in less than an hour. Is that fast enough for you?

Hayward W3H400FDN vs H400FDN / Pool Heaters

Features / W3H400FDN

The W3H400FDN is a new design from Hayward, and even though it doesn’t look much different than the old model, the changes are where it matters most — the internal components are designed to give you faster heating and greater energy efficiency. After all, isn’t that what matters most?

This new H-Series from Hayward is engineered to make it easy to fit into any pool installation. You get the option of connecting the gas and water from the left or right side of the pool heater. It’s streamlined making it lighter with a lower-profile than its predecessor. The front control panel makes it easy to program and use. It also produces extremely low NOx emissions. Below you can see the range of advanced features you get.

This series is available in a variety of sizes: offered in 150,000, 200,000, 250,000, 300,000, 350,000 and 400,000 BTU/hr. models.

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Hayward W3H400FDN Features

If you’re environmentally conscious then you’ll like the fact that the Hayward W3H400FDN is a low emissions NOx (mono-nitrogen oxides) heater that operates at optimal efficiency while complying with all current California air quality emission standards. Just to be clear, buying the Hayward H400FDN won’t save the planet from climate change but you can be confident in knowing you made the best choice possible when it comes to heating your pool. That’s all.

Hayward has filled the Hayward H400FDN with a lot of technology, including: stainless steel burners, corrosion-resistant heat exchangers and insulated fire tile combustion chambers, which traps heat far more effectively than other insulation allowing it to maximize every BTU.

It has an easy-to-read LED control panel, which monitors the overall performance of the Hayward W3H400FDN. It’s a convenient interface that requires very limited effort on your part to understand and control the pool heater.

The ignition system is activated with the simple touch of a button. Engineered with a forced draft system that constantly and precisely moves air through the combustion chamber. In addition, the Hayward W3H400FDN is not affected by the weather, including wind. That’s correct, it’s been designed in such a way that to completely eliminate any weather fluctuations. Well, unless a tornado hits it, but you know what I mean. Every day weather won’t affect your Hayward H400FDN pool heater.

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Selecting the correct size Hayward H-Series Heater:

If you’re buying a Hayward pool heater for the first time then you need to do some calculations before deciding upon the correct BTU capacity. See the chart below.

Further below in this article you’ll find a chart to determine the correct size for your spa or hot tub.

NOTE: This heater is designed so that it can be installed with the water connections located on either the right or left side.

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Installation | Hayward H400FDN — & other H-Series Pool Heaters

If you’re someone who is capable of installing the Hayward H400FDN then you need to watch the video below which is shows you how to install it. On the other hand, if you’re not mechanically inclined, don’t worry about installing this pool heater yourself. My suggestion is to order it online — which will save you a lot of money, then take some of that money and hire a certified technician to install it for you. Make sure he or she is certified in order to maintain your warranty.

Installation should not cost you more than a few hundred dollars.

You might want to consider getting a larger Hayward pool heater than you actually need to increase the speed of heating up your pool. If you’re impatient then this is an option that many pool owners choose. If you go this route, just get one size larger.

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Hayward H400FDN | Start-up & Troubleshooting

View or download the following documents for the Hayward H400FDN, or any other Hayward H-Series Pool Heater models:

1. MANUAL — Hayward H-Series Pool Heater
2. PARTS — Hayward H-Series Pool Heater
3. GUIDELINES — Hayward H-Series Pool Heater
4. SERVICE & INSTALLATION — Hayward H-Series Pool Heater

NOTE : Since these pool heaters are expensive you might be happy to know that if you buy a Hayward H-Series Pool Heater using a Amazon.com Store Card you pay no interest for 12 months if your entire order is paid in full at the end of 12 months. It’s something to consider if money is tight at the moment. The choice is yours.

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Shipping the Hayward W3H400FDN

If you’re concerned about buying such an expensive (and heavy) product online I just want to put you at ease. You don’t really have to do anything. First of all, if you’re an Amazon Prime member the delivery will be free, so if you’re not already a member then I suggest you sign-up. It will pay for itself immediately.

Next, after you order it online, Amazon will schedule an appointment for delivery because they need someone to sign for it when it arrives. It’s an expensive item so they want to make sure that you receive it.

It will be delivered on a small pallet so it can be moved by dolly. When the Hayward H400FDN arrives, just tell the delivery person exactly where you want it and they’ll take it there. It’s actually effortless on your part. Don’t worry.

When you get this delivered, just tell the person to place the H400FDN where you will have it installed so you don’t break your back trying to do it after he leaves. It will be shipped on a pallet to protect it during shipping.

Learn more about the Hayward H400FDN on Amazon.

Features (Hayward H400FDN):

• Forced draft system moves air consistently & precisely through the combustion chamber.
• Weather does not effect heating performance, including wind.
• Finn Plate heat exchanger with a special V-groove design = long life, fast heating and virtually no condensation.
• Made from Cupronickel. Highly durable even in salt-based, high flow or aggressive water chemistry set-ups.
• Dual Voltage : Voltage adapts to either 110V or 220V.
• Universal Wiring Junction Boxes. Versatile left and right side junction boxes.
• Hot Surface Silicon Nitride Ignition System.
• Clear LED digital panel provides temperature readout and diagnostics for easy identification of components that might need servicing.
• Polymer header provides reliable hydraulic performance; saving you energy and protecting against the destructive effects of erosion from high flow conditions.
• Designed for modern larger diameter plumbing systems with 2″ x 2.5″ CPVC unions.
• Low NOx Emissions.
• 1 Year limited warranty.

Specs:

• 400,000 BTU
• Gas: Natural
• Ignition: Electronic
• Thermostat: Dual
• Weight: 197 lbs.
• Width: 36.5″

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Selecting the correct Hayward H-Series Heater for your hot tub or spa:

If you’re buying the Hayward H250FDN for your spa or hot tub then view the reference table which lists the time required in minutes to raise the temperature of the spa/hot tub by 30˚F.

Locate the column with the spa/tub size in gallons that is closest to yours. Select the desired time to raise the spa/hot tub temperature 30˚F, read to the left and select the appropriate H-Series model.

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H-Series Pool Heater Specs | Natural Gas

As with all the Hayward H-Series pool heaters, the H250FDN will save you money in the long run because it’s highly efficient at heating your pool, spa or hot tub. Hayward has done an excellent job at engineering a pool heater that works quickly and reliably. And by the way, all of the Hayward H-Series pool heaters look the same.

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Here are the technical specifications for the different models:

All of the models look identical but the physical size (and weight) are different based on the specific model.

— Hayward H150FDN

Learn more from Amazon.

Specs:

• 150,000 BTU
• Carton Weight: 141 lbs.
• Width: 21.5″
• Gas: Natural
• Ignition: Electronic
• Thermostat: Dual

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— Hayward H200FDN

Learn more from Amazon.

Specs:

• 200,000 BTU
• Carton Weight: 154 lbs.
• Width: 24.75″
• Gas: Natural
• Ignition: Electronic
• Thermostat: Dual

Engineered with High-Quality Materials

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— Hayward H250FDN

Learn more from Amazon.

Specs:

• 250,000 BTU
• Weight: 165 lbs.
• Width: 28″
• Gas: Natural
• Ignition: Electronic
• Thermostat: Dual

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— Hayward H300FDN

Learn more from Amazon.

Specs:

• 300,000 BTU
• Weight: 180 lbs.
• Width: 30″
• Gas: Natural
• Ignition: Electronic
• Thermostat: Dual

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— Hayward H350FDN

Learn more from Amazon.

Specs:

• 350,000 BTU
• Weight: 195 lbs.
• Width: 33.25″
• Gas: Natural
• Ignition: Electronic
• Thermostat: Dual

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Should you buy Hayward W3H400FDN?

Well, in short – yes. The Hayward W3H400FDN, and all H-Series heaters, are incredibly fast at heating swimming pools, spas and hot tubs. Yes, there are many other pool heaters on the market but Hayward is a brand with a strong reputation. After 80 years in business they should know what they’re doing — and they do.

This heater will last you many years to come and don’t forget that you’ll save money compared to other brands because it operates so efficiently. I can’t stress that enough. It’s an investment. Evaluate the cost over the long-term.

Learn more about the Hayward H400FDN in our article on above ground pool heaters. We go into more detail on this pool heater series.

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