Universal H-Series Low NOx Heater 250K BTU - LP - W3H250FDP



Part # W3H250FDP

By Hayward Pool Products

  4.8 Average  



Part # W3H250FDP

Warranty 1 Year

Alternate Part #'s HAYW3H250FDP

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

250,000 BTU
165 lbs.
28 in.
0-10,000 ft.
Heat Exchanger:
Cupro Nickel
Special Feature:
Low NOx Emissions

?     Asked on 2/2/2021 by Dawn

Hi - I am trying to decide which propane unit would be best for me at an altitude of 6000 feet. We have an oval above ground 15 x 30 x 4 ft. deep pool. I have looked at the Hayward, Raypak, and Pentair units, but can't decide. Thanks.

A  Answered on 2/3/2021 by InyoPools Product Specialist Joe S.

Good day, Dawn, we would recommend the Hayward Pool Products Universal H-Series Low NOx Heater 250K BTU - LP for your set up. It can work with the high altitude and comes with a Curpo Nickel heat exchanger.

  • Commented on 2/3/2021 by Product Owner

    I bough a Raypak pump and filter last year after having had a Hayward for many years. Any issues with compatibility? Thanks.

    • Commented on 2/18/2021 by InyoPools Product Specialist Hector F.

      Hi Dawn, as long as your system provides adequate water flow and they are not controlled by another brand automation system then there should not be a compatibility issue. 

?     Asked on 10/14/2020 by Gihan Seraka

im looking to install a gas heater for my 15,000 gallons inground pool how much BTU do i have to pick

A  Answered on 10/23/2020 by InyoPools Product Specialist Joe S.

Hello Gihan, thank you for contacting INYO POOLS. Here is a Sizing Your Pool Heater Guide that will help you find the correct unit.

?     Asked on 5/7/2020 by Boland Robert

my pool heater is reading Lo,i had it set for 85 degrees it stoped heating

A  Answered on 1/20/2021 by InyoPools Product Specialist Hector F.

Hi Boland, most often the LO refers to the pressure switch, water pressure. This can be caused by either the diaphragm in the flow switch has failed or the filters are clogged and/or the pump is unable to make enough pressure to make the switch.

?     Asked on 4/22/2020 by dennis

I have a 30,000 gallon pool with a 1.5hp pump, LP gas, in East Texas, what size heater do you recommend ?

A  Answered on 11/5/2020 by InyoPools Product Specialist Hector F.

Hi Dennis, there are a few variables to consider when sizing a pool heater. Here is a guide that we put together called "Sizing Your Pool Heater" that should help. 

?     Asked on 2/27/2020 by

is the heater 110 or 220v?

A  Answered on 2/27/2020 by InyoPools Product Specialist Lennox H.

Hi. This heater is dual voltage, so it can operate using 110 or 220 volts. 

?     Asked on 12/26/2019 by NANCY L MILES

How do you clear a CE error on display pad? How do you re-establish the correct communication between the ignition board and display board?

A  Answered on 12/26/2019 by InyoPools Product Specialist Lennox H.

Hi, Nancy. You can follow these steps. A. Power down heater and re-power. This is similar to rebooting a computer. B. If rebooting does not solve the problem, inspect the display interface wiring. Ensure the display interface plug is securely attached to the control module. C. If steps A & B do not resolve the CE error, the Control Board - FDXLICB1930 and/or Display PCB - IDXL2DB1930 are defective and must be replaced.

?     Asked on 8/22/2019 by Maria Robinson

Hello, our pool heater is not heating. It has an F1 alarm code

A  Answered on 8/22/2019 by InyoPools Product Specialist Lennox H.

Hi, Maria. I was not able to cross reference that error code to a specific issue. Please reverify the code.

?     Asked on 5/16/2019 by Jeff

I live on Staten Island NY and was wondering if this product is appropriate for this region.

A  Answered on 5/16/2019 by InyoPools Product Specialist Lennox H.

Hi, Jeff. Yes, this heater is appropriate for that region.

?     Asked on 5/25/2017 by tom

I have a 12,000 gallon outdoor salt water pool. What size heater do I need?

A  Answered on 5/25/2017 by InyoPools Product Specialist Scott W.

What state do you live in so I can better answer your question?

?     Asked on 7/3/2016 by Alvin Alexander

I currently have an older model of this unit. I have a vertical vent pipe that vents through the roof. Can I operate this newer unit without the vent pipe?

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

Hi Alvin, This unit will also require a vent kit for indoor installation.

?     Asked on 8/30/2015 by

I want to change my CPS 1320 heater to a current model what do you suggest, roughly a 30000 gal pool

A  Answered on 9/3/2015 by InyoPools Product Specialist Lennox H.

Hi, For your size pool I would recommend the H300FDP. If you would like to heat the pool faster you can go with a larger size unit also.

?     Asked on 5/8/2015 by Gabriel Suarez

I have a in-door pool with 22000 gallons, I want to buy your: Hayward, H250FDP, will be OK?

A  Answered on 5/9/2015 by InyoPools Product Specialist Patrick P.

Hi Gabriel, This would be the correct sized heater for a 22,000 gallon pool.

?     Asked on 5/4/2015 by Emilio Ramirez

Im interested in a pool heater for an outside pool with following dimensions: 30 feet long x 10 feet wide 5.5 feet deep. I have LP gas, and would like to be able to use it in the fall temperatures may be -5 Deg Celsius. Will a 250 be suitable for this pool? I run a single speed 3/4 H.P. pump/filter Thanks!

A  Answered on 5/5/2015 by InyoPools Product Specialist Patrick P.

Hi Emilio, Yes this heater would suit your needs. Based on the information you supplied on your pool you would expect to see a 1-2 degree (Fahrenheit) temperature rise per hour. In the colder months we would definitely suggest a Swimming Pool Solar Cover as this will significantly reduce your operational costs of the heater.

?     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.


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