Universal H-Series Low NOx Heater 300K BTU - LP - H300FDP


Part # H300FDP

By Hayward Pool Products

  5 Average  



Part # H300FDP

Product Description

Residential Gas Heater Sizing

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

300,000 BTU
180 lbs.
30 in.
0-10,000 ft.
Heat Exchanger:
Cupro Nickel
Special Feature:
Low NOx Emissions

?     Asked on 8/26/2019 by Augusto A Calles

my pools is 25,000 liter of water 300k btus will be ok for my pool?

A  Answered on 8/26/2019 by InyoPools Product Specialist Lennox H.

Hi, Augusto. This will be more than sufficient to heat a pool that is 25,000 liters. 

?     Asked on 12/10/2018 by Steve D Johnson

my gas spa heater model H300 has a loud "KNOCK" white heating been told there is sediment in the heat unit How do I fix this ?

A  Answered on 12/11/2018 by InyoPools Product Specialist Lennox H.

Hi, Steve. You will need to remove and inspect the heat exchanger. Running water through the unit can remove any loose sediments. 

?     Asked on 4/10/2018 by Jeff

I have never had a pool heater before, I have an in-ground pool about 30,000 gallons. I live in the south and just want to heat the pool up earlier in the season. My question is can I use the heater part time? I don't know if I would let the water run through it while it is off, or should I put a bypass for when I am not using the heater. Would this hurt the heater?

A  Answered on 4/10/2018 by InyoPools Product Specialist Lennox H.

Hi, Jeff. You can use your heater as you see fit. It is best not to run water through the heater when it's not in use. It would not hurt the unit, however, I would recommend that you install a manual bypass. FYI, drain the water out of the unit when water is being bypassed.

?     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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1 Ratings
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