---
product_id: 812708
title: "Hayward H400FDN Universal H-Series 400,000 BTU Pool and Spa Heater, Natural Gas, Low Nox"
brand: "hayward"
price: "₨3887134"
currency: LKR
in_stock: true
reviews_count: 3
url: https://www.desertcart.lk/products/812708-hayward-h400fdn-universal-h-series-400-000-btu-pool-spa
store_origin: LK
region: Sri Lanka
---

# 400,000 BTU Universal design Low NOx Hayward H400FDN Universal H-Series 400,000 BTU Pool and Spa Heater, Natural Gas, Low Nox

**Brand:** hayward
**Price:** ₨3887134
**Availability:** ✅ In Stock

## Summary

> 🌊 Dive into Comfort with Hayward's H-Series Heater!

## Quick Answers

- **What is this?** Hayward H400FDN Universal H-Series 400,000 BTU Pool and Spa Heater, Natural Gas, Low Nox by hayward
- **How much does it cost?** ₨3887134 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.lk](https://www.desertcart.lk/products/812708-hayward-h400fdn-universal-h-series-400-000-btu-pool-spa)

## Best For

- hayward enthusiasts

## Why This Product

- Trusted hayward brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Durable Construction:** Featuring a cupro nickel heat exchanger for superior reliability and longevity.
- • **Hydraulic Efficiency:** Patented polymer header and bypass valve design ensures optimal performance.
- • **Effortless Installation:** Designed for easy, versatile installation by professionals, saving you time and hassle.
- • **Unmatched Heating Power:** Experience the warmth of 400,000 BTUs, perfect for any pool or spa.
- • **Eco-Friendly Performance:** Stay compliant with low NOx emissions while enjoying your leisure time.

## Overview

The Hayward H400FDN Universal H-Series Pool and Spa Heater delivers an impressive 400,000 BTUs of heating power, designed for natural gas use. Its low NOx emissions make it an environmentally responsible choice, while the durable cupro nickel heat exchanger and patented polymer header ensure reliability and efficiency. Perfect for professional installation, this heater is the ultimate solution for pool and spa enthusiasts.

## Description

Product Description          EXPERT LINE products are only available through your local pool professional. The Universal H-Series is an energy efficient, high performance, installation adaptable commitment to the pool service professional. Standard cupro nickel heat exchanger Excellent salt water and chemical corrosion resistance Exclusive "Totally Managed" cupro nickel heat exchanger water flow Same water velocity through all tubes for faster heating Patented header by-pass design Up to 18 percent savings by reducing pump run-time 2in x 2 1/2in CPVC union plumbing connections Common union for installation or service, adapts to larger plumbing recommended for greater efficiencies Low NOx emissions - meets clean air quality standards Energy Calculator Ctn. Qty. 						 							 								1 							 						 					 				 					 						Ctn. Weight 						 							 								214.0 lbs.             From the Manufacturer          The Hayward Universal H-Series gas heater is the “universal” energy efficient remedy for any new or existing pool or spa. An industry leading hydraulic design reduces circulation pump run time to provide energy savings of up to 18% when compared to less efficient competitors. The energy efficiency of the Universal H-Series gas heater combines with low Nox emissions, a standard Cupro nickel heat exchanger and ultimate installation flexibility on new or existing equipment pads to responsibly heat a pool or spa today and for years to come.

## Features

- Standard Cupro nickel heat exchanger for superior value and reliability
- Patented polymer header and bypass valve design for the ultimate in hydraulic efficiency and reliability
- Hayward Universal design for easy and versatile professional installation
- Environmentally responsible low NOx emissions to meet or exceed air quality emission standards in all Low NOx regions

## Images

![Hayward H400FDN Universal H-Series 400,000 BTU Pool and Spa Heater, Natural Gas, Low Nox - Image 1](https://m.media-amazon.com/images/I/61REygb2bSL.jpg)

## Questions & Answers

**Q: Does this thing run off of one of those propane grill tanks?**
A: Yes, there is a propane model. No, it does not run off 20 lb propane tanks. I have a 250 gallon underground propane tank that was installed with the pool and heater. I do not have NG in my neighborhood, so propane was the only option for me. Those that answered this question with sarcastic and frankly insulting comments should be more familiar with the product BEFORE they put their comments online . They are the ones who look stupid not knowing how to answer this simple question.

**Q: my pool takes 36,000 galloons, will this heater work?**
A: Well, my pool is 21,000 gallons and it works quite well indeed.  When I started it for the season last week it raised the pool temp from 63F to 84F in just about 24 hours.  I imagine it would work well in your pool.  Obviously, it will take longer to heat the additional 15K gallons, but it should work.

**Q: will this unit work with an in-ground pool and spa in Florida?**
A: Yes.  This heater will raise the temperature of a 20 x 40 pool 1-2 degrees per hour.  An 8' spa takes about 15 minutes to get to 102 degrees.

**Q: When the heater fires I get a lot of steam out the back after a few min. it  stops.**
A: Mine steams for a few seconds when it first fires up as it burns off any condensation but that is it. It should not steam for longer than that. Sounds like a cracked pipe inside the unit. I would check with hayward, they have a great helpline.

## Customer Reviews

### ⭐⭐⭐⭐⭐ So far it's great
*by C***Y on May 2, 2014*

DELIVERY: The folks who delivered it called a day ahead and confirmed the schedule. I asked them to give me a call 30 minutes prior so I didn't have to leave work too early and they said no problem. I received a robocall saying they would be there in a hour. They ended up being there in 30 minutes after all so I almost missed them. The deliveryman took it around to the back of the house and placed it right beside the pad where it would be installed which was much appreciated. It was well packed on a pallet and after the screws attaching it to the pallet were removed, it came off without much effort. I was worried it would be too heavy for just 1 person, but it was able to be 'walked' off the pallet into position.INSTALL: The house we bought last summer used to have a pool heater, but apparently it broke and the previous owner decided to eliminate it instead of replace it. So my install required cutting off the PVC pipes that were installed to reroute the water without the pool heater and run them into the heater and then run the gas line from the existing stub around to the other side of the heater and then run the electric. I have very little experience dealing with PVC. So I researched and talked to the guy at the local plumbing store and finally felt confident. It wasn't tough at all. Just make sure the cuts are square and smooth, then I used a cleaner, a primer and the cement to assemble to pipes. PVC connections are a little forgiving since they are chemically welded. Don't forget to install the threaded rings on the pipes before you glue them to the supplied heater manifold or you will do what I did and have to cut the PVC, install the threaded rings and then use a connector to seal it all back up. It ended up not being as pretty of a job as I would like, but it worked. I have ZERO experience with gas line installs, but this one was very straight forward. I just ran the 3/4" line from the stub and routed it to the gas connector on the heater. I used flexline to go from the end of the black pipe to the connector on the heater. Then I turned on the gas, checked for leaks and deemed it good to go. The electrical ran from an existing junction box through plastic conduit to the connectors on the heater. Once everything was hooked up, it fired up and operated perfectly.PERFORMANCE: Upon initial use, it did give off a smell as others have said. Each subsequent use the smell diminishes. I attribute it to a coating on the heat exchanger vice simple packing oil. Packing oil would have burned off quickly. It's not obnoxious and will probably be gone very soon. It raises my 17,000 gallon pool 3 degrees per hour just as advertised. This is my second pool with a heater. The other was a Jandy Lite 2. The controls are similar, but the Hayward controls are simpler and work well. It does take longer for the Hayward to light off, but it really doesn't make a difference. The Hayward is more compact and would be my choice between the two. The heater will not run unless it detects a minimum volume flow. I have a 2 speed pump and the heater will not operate if the pump is set on its low speed. Sometimes it will continue to operate of the pump switches from high to low though, so it's probably right on the edge. The minimum flow volume required by the heater is adjustable and I may be able to adjust it such that it will run if the pump is on low. I will follow up after I try that.SUMMARY: Straightforward install, compact design, performs as advertised. It has been installed for a little over a month and I'm very happy with the purchase.

### ⭐⭐⭐⭐ Pretty good workhorse with one caveat.
*by D***. on July 19, 2025*

Okay. So I purchased this 11 years ago so I believe I’m qualified to give a sound review. The heater still works fine and is a workhorse. The only reservation is that the control panel is subject to not operating when it rains. The rain seeps somehow into the control panel. I say this for one important reason. If it has rained heavily and you see a “CE” control error message, be patient and wait a few hours or a day to see if it has dried and operating. This will save you a lot of money and heartache calling technicians for unnecessary repairs. Like I said, it’s been working for 11 years with only this hang up.

### ⭐ HAYWARD DOES NOT HONOR THEIR WARRANTY!!!
*by T***M on June 18, 2018*

I purchased and installed my heater in April 2017 in accordance with the installation instructions, including verifying both water flow and gas pressures. The heater failure light illuminated after 10 months of intermittent use. I determined the problem to be a blown thermocouple on the exhaust gas circuitry which is among a series of safety switches, all of which must be closed to enable the start sequence. Failure of this exhaust gas component, according to the Hayward manual, requires that the heat exchanger be replaced. Upon this discovery, I called Hayward to discuss a warranty replacement. I can honestly state that in my 69 years, I have never spoken to a more arrogant and interruptive representative of any company. Immediately. I was told the heat exchanger did not have to be replaced and that there was no warranty on an owner installed heater, regardless of defect! I was told that the failure was caused by the fact I had installed the heater gas supply incorrectly (notwithstanding that I hold patents on Industrial devices which employ far more complex circuitry and gas pressure regulation than the cheaply built Hayward HDF 400,000 BTU Pool Heater!) Realizing that any further discussion with Hayward was completely useless, I replaced the thermocouple with a unit of similar limits which I purchased from a local HVAC supply house, cleaned the heat exchanger, verified the incoming and manifold gas pressures and returned the heater to service.The heater failed again this past weekend for the same reason. I am now researching other heater manufactures and will report my selection when determined. I am actually looking forward to throwing the Hayward into the dump if for no other reason than the terrible and disrespectful treatment I received from Hayward during my call for assistance.I STRONGLY RECOMMEND THAT THAT NO ONE PURCHASE A HAYWARD POOL HEATER UNLESS YOU WISH TO REPLACE IT EACH SPRING AND DO NOT WANT A WARRANTY!

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*Product available on Desertcart Sri Lanka*
*Store origin: LK*
*Last updated: 2026-03-02*