Universal H-Series Low NOx Heater 500K BTU - NG - H500FDN


Part # H500FDN

By Hayward Pool Products



Part # H500FDN

Product Description

Universal H-Series Low NOx Heaters 
For In-Ground Pools and Spas - Electronic Ignition Dual Thermostat

Now With Cupro Nickel Heat Exchanger!

NEW Hayward Universal H-Series Low NOx heater combines industry-leading hydraulic performance; environmentally responsible low NOx emissions and a standard cupro nickel heat exchanger with a low profile appearance, lighter weight design, independent left or right side electric, water and gas connections plus 2" x 2 1/2" CPVC union connections to provide the ultimate installation flexibility for new or existing equipment pads. 

It also includes a forced draft system that constantly moves air through the combustion chamber at a precise flow rate. As a result, all outside weather variables that can affect the heating performance, such as wind conditions, are eliminated - without having to install a high-wind stack. 

NOTE: The Hayward Universal H-Series heaters meet the NOx Emission standards set by the California South Coast Quality Air Management Commission for 2001 and the Texas Natural Resource Conservation Commission Code. 


  • Forced draft system constantly moves air through the combustion chamber at a precise flow rate, eliminating all outside weather variables that can effect the heating performance, such as high wind conditions -- without a high wind stack.
  • Our patented single header "V" baffle design heat exchangers allow for long life, fast heating and virtually no condensation. All Hayward heat exchangers are now constructed with highly resilient Cupro Nickel for greater durability and longevity even in salt-based, high flow or aggressive water chemistry set ups.
  • Easy-to-read L.E.D. digital Control Panel provides digital temperature readout and diagnostics for quick identification of components that might need service.
  • New polymer header provides superior hydraulic performance to save energy and protect against the damaging effects of erosion from high flow conditions for improved reliability.
  • Designed for today's larger diameter plumbing systems with 2" x 2 1/2" CPVC unions.
  • 1 Year limited warranty
  • Now with Cupro Nickel Heat Exchanger

Overall Dimensions

Product Specifications

500,000 BTU
0-10,000 ft.
Heat Exchanger:
Cupro Nickel
Special Feature:
Low NOx Emissions

?     Asked on 5/21/2019 by Rozum

Does the 500k model require a vent inside a pool house?

A  Answered on 5/21/2019 by Industry Professional

You would require an indoor horizontal or vertical vent adapter. Here is the Hayward H500 Vertical Vent Adapter and here is the Hayward H500 Horizontal Vent Adapter.

A  Answered on 6/17/2019 by Industry Professional

Yes, If used inside a buidling it needs to be vented

?     Asked on 2/10/2017 by Ryan

I have a 65,000 gallon pool and am planning to add a heater. Pluming was already designed to accommodate a heater addition along with 1 1/4" Natural gas line to the plumbing skid. My question is what size heater should I use? Should I tee my plumbing and do parallel heaters? My control logic is Hayward.

A  Answered on 2/10/2017 by InyoPools Product Specialist Scott W.

Hi Ryan, 1-1/4" gas piping would be the correct size for a propane heater, for a natural gas heater the correct gas piping size is 3/4".

?     Asked on 9/23/2016 by TERRENCE J McLaughlin

I have 60000 gallons of water that I need to maintain at 82F. Can I do this with one 500000 btu heater or two. Currently I have one Laars 1000000 btu which I want to replace.

A  Answered on 9/29/2016 by InyoPools Product Specialist Scott W.

The H500FDN would do the job. It will not heat it nearly as fast as you are used to with the 1M BTU Laars, but it will do the job.

?     Asked on 7/3/2016 by Kriss Karp

I have a pentair intellitouch with screen logic, if I go with a Haward heater do I loose any functionality to my automation as compared to the Pentair 461201

A  Answered on 7/9/2016 by InyoPools Product Specialist Lennox H.

Hi Kriss, Wiring this heater to the Pentair IntelliTouch will only give basic control like adjusting the temperature and turning on/off the unit.

?     Asked on 4/26/2016 by jim

How long does it take to heat pool the size of 20x40x9 and what heater would you recommend??

A  Answered on 4/27/2016 by InyoPools Product Specialist Lennox H.

Hi Jim, Unfortunately, we do not have the performance data needed to calculate the heating time for this unit. Your pool surface area is 800 sq.ft, so Hayward recommends a minimum size of 300K BTU, you can always go with a larger unit which will heat the pool faster.

?     Asked on 4/21/2015 by George

I want to install the Hayward Lownox heater on my pool but I live in the mountains at 3,000 foot elevation; do I need to buy a special high elevation heater?

A  Answered on 4/21/2015 by InyoPools Product Specialist Matt S.

Hello George, The Hayward Universal Low Nox are self adjusting up to 10,000 feet of elevation. Any installation above 2,000 feet will require a special restriction plate to be installed. Luckily, that plate comes standard with every heater so no need to purchase it separately.

?     Asked on 10/8/2013 by Guest

Where can my heater be installed?

A  Answered on 10/8/2013 by InyoPools Product Specialist Patrick P.

There are specific venting requirements and clearance distances that must be met to ensure proper operation. Consult the owner’s manual for exact specifications for your model of heater.NOTE: Gas fired heaters should be diagnosed and repaired by trained personnel.

?     Asked on 1/17/2013 by Guest

Is a vent required for typical outside installation for the Hayward 150k Ng Lo Nox heater?

A  Answered on 1/17/2013 by InyoPools Product Specialist Patrick P.

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.

?     Asked on 10/18/2012 by Guest

What is the elevation rating for the Hayward H-Series Low Nox Heaters

A  Answered on 10/18/2012 by InyoPools Product Specialist Patrick P.

Per Hayward, the Hayward H-Series Low Nox Heaters have an elevation rating up to 7,700'

?     Asked on 10/10/2012 by Guest

What is the difference between an Electronic and Millivolt ignition?

A  Answered on 10/10/2012 by InyoPools Product Specialist Patrick P.

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.

?     Asked on 1/16/2012 by Guest

Will a gas heater operate at the low speed of a dual speed motor?

A  Answered on 1/16/2012 by InyoPools Product Specialist Patrick P.

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.

?     Asked on 12/29/2011 by Guest

How do you know if a pool heater is a propane heater or a natural gas heater?

A  Answered on 12/29/2011 by InyoPools Product Specialist Patrick P.

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.