?     Asked on 12/29/2011by Guest

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

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.
 Reply


?     Asked on 1/16/2012by Guest

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

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.
 Reply


?     Asked on 10/10/2012by Guest

What is the difference between an Electronic and Millivolt ignition?
 Reply

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.
 Reply


?     Asked on 10/18/2012by Guest

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

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'
 Reply


?     Asked on 1/17/2013by Guest

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

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.
 Reply


?     Asked on 4/28/2013by Guest

How can I tell the difference between a Propane or Natural Gas heater listed on your website?
 Reply

A  Answered on 4/28/2013 by InyoPools Product Specialist Patrick P.

A heater's model number will usually end with an 'N' or a ''P' to denote the gas type. if the model number is only numbers we also have the gas type in the description of the product. The abbreviations "NG" is for natural Gas and "LP" is form Liquid Petroleum, also called Propane.
 Reply


?     Asked on 10/7/2013by Guest

Is it possible to convert this heater from natural gas to propane?
 Reply

A  Answered on 10/7/2013 by InyoPools Product Specialist Patrick P.

Yes, it is possible to convert this heater from natural to propane gas as there is a conversion kit for it. To view and purchase this kit you you will need to click here.
 Reply


?     Asked on 10/8/2013by Guest

Where can my heater be installed?
 Reply

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.
 Reply


?     Asked on 10/2/2014by Guest

Heater model # H400FDN, can be used on pools of all different sizes? The larger the BTU's the quicker the pool will get warm
 Reply

A  Answered on 10/2/2014 by InyoPools Product Specialist Patrick P.

The required size of a heater depends on the size of your pool or spa and how fast you want to heat up your pool. In the northern states you will probably want the larger heaters to compensate for the colder temperatures. Above ground pools use heaters from 55K to 130K BTUs. In ground pools and spa general run from 100K to 400K BTU. For an average 15' x 30' pool (15,000 gallons), a 300K BTU heater would raise your pool temperature 2 degrees per hour; a 400K BTU heater, 2.7 degrees per hour. For a 20' x 30' pool (20,000 gallons) the temperature rise for 300K and 400K heaters would be 1.5 and 2 degrees respectively. By contrast these same heaters would raise the temperature of an average size spa 30 degrees in 35 and 20 minutes respectively.
 Reply


?     Asked on 4/19/2015by Inyo Visitor

I would like to replace an older Model H400 IDL serial n°30831409 dated 2002 with this Low Nox 400K NG. Is this the right choice? Will the new unit be compatible with the existing external electronic panel control?
 Reply

A  Answered on 4/20/2015 by InyoPools Product Specialist Patrick P.

Yes the H400FDN would be the correct replacement for the H400IDL heater. Yes this heater would be compatible with any external controller you were using on the H400IDL.
 Reply


?     Asked on 4/21/2015by 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?
 Reply

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.
 Reply


?     Asked on 5/21/2015by Jack Green

When wiring this heater is it 110 or 220?
 Reply

A  Answered on 5/21/2015 by InyoPools Product Specialist Patrick P.

Hi Jack, This heater can be wired either 110V or 220V, it comes set up for 220V but can be easily converted to 120V by removing the 220V jumper.
 Reply


?     Asked on 9/6/2015by tammy

is there any specific winterizing instructions the manual does not have any.
 Reply

A  Answered on 9/10/2015 by InyoPools Product Specialist Lennox H.

Hi Tammy, You can find the Winterizing Instructions in the Hayward H-series LoNox Installation Guide.
 Reply


?     Asked on 2/19/2016by Inyo Visitor

do all the heaters have a right side connection or do you have to order it that way?
 Reply

A  Answered on 2/19/2016 by InyoPools Product Specialist Megan C.

Normally heaters are factory set to the rights side for connection. The H400FDN is factory set to the right, it may be reversed by a Certified Pool Technician before installation.
 Reply


?     Asked on 3/27/2016by Rich

Can this heater be installed outside and used in all weather conditions?
 Reply

A  Answered on 3/28/2016 by InyoPools Product Specialist Lennox H.

Hi Rich, This unit can be installed outside and can be used in all weather conditions. Please refer to the Hayward Universal H-Series Owner's Manual for winterizing instructions.
 Reply


?     Asked on 5/21/2016by Inyo Visitor

when is the date of delivery
 Reply

A  Answered on 5/22/2016 by InyoPools Product Specialist Alex V.

Hello, Freight deliveries can take 5-10 business days.
 Reply


?     Asked on 5/25/2016by Chuck

Can I control a Hayward H400FDN heater with my Jandy AquaLink RS control system?
 Reply

A  Answered on 5/29/2016 by InyoPools Product Specialist Lennox H.

Hi Chuck, The H400FDN can be wired and or controlled by a Jandy Aqualink RS controller.
 Reply


?     Asked on 6/7/2016by Matt

I have an existing 1-1/4" gas line run at around 140'. Will that be sufficient for this heater?
 Reply

A  Answered on 6/11/2016 by InyoPools Product Specialist Lennox H.

Hi Matt, According to the Hayward H-series LoNox Installation Guide you will need 1-1/2" pipe.
 Reply


?     Asked on 12/9/2016by Bill

how do i properly winterize my hayward h 250 ? as far as i can see they tell you to open the drain on the header. this doesn't seem to be enough.
 Reply

A  Answered on 12/9/2016 by InyoPools Product Specialist Lennox H.

Hi, Bill. Draining all of the water from the unit is all it takes to winterize the unit. You can take it an extra step and get a heater cover to protect the unit from the cold.
 Reply


?     Asked on 2/21/2017by Inyo Visitor

Is the keypad cover on this unit or does it need to be purchased separately? Does price include shipping?
 Reply

A  Answered on 2/21/2017 by InyoPools Product Specialist Scott W.

Yes, the keypad cover comes with the unit and the price includes shipping.
 Reply


?     Asked on 5/25/2017by Arnold Zaffos

With regards to the Hayward H400FDN, is the cover a new design for 2017?
 Reply

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

Yes, the new design has a cover on the key pad.
 Reply


?     Asked on 6/6/2017by Jeff

What size propane line is required?
 Reply

A  Answered on 6/12/2017 by InyoPools Product Specialist Lennox H.

Hi, Jeff. The Hayward H-series LoNox Installation Guide provides the gas line info on page 22 under Gas Supply and Piping.
 Reply


?     Asked on 8/24/2017by Elisha

I ordered this heater, Is there a service installed?
 Reply

A  Answered on 8/25/2017 by InyoPools Product Specialist Joe S.

Good afternoon, for a list of installers you will need to review Hayward's Dealer locator. All you need to do is Enter a postal code to find the nearest Hayward authorized pool professional.
 Reply


?     Asked on 9/20/2017by Steve

What is the best way to determine the BTU size of heater required for my pool? I currently have a 406,000 BTU unit and my pool is 27,000 gallons.
 Reply

A  Answered on 9/20/2017 by InyoPools Product Specialist Lennox H.

Hi, Steve. Our Sizing A Pool Heater Blog has all the steps you'll need. 
 Reply


?     Asked on 11/22/2017by Patrick S.

Can turn this pool heater on and off whenever I want? or once I turn it on for the season (say April), I have to keep it on running 24/7 until I winterize it in September? Is there a "On/Off" button? I live in PA, 45'X25' pool
 Reply

A  Answered on 11/22/2017 by InyoPools Product Specialist Lennox H.

Hi, Patrick S. You can put the unit in STANDBY mode which will turn the Heater off. 
 Reply


?     Asked on 1/4/2018by Mike

I have a 15 year old Teledyne Laars 400000 BTU heater supplied by three-quarter inch natural gas line. Is the 3/4 inch gas line existing going to be enough to supply this heater they are both 400000 btus. Thx. Mike
 Reply

A  Answered on 1/5/2018 by InyoPools Product Specialist Lennox H.

Hi, Mike. A 3/4 gas line is sufficient for specific applications, refer to page 22-24 of the Hayward H-series LoNox Installation Guide
 Reply


?     Asked on 4/16/2018by CURT

WE HAVE A jANDY HEATER AT THIS TIME BUT THE CONTROL PANEL HAS GONE BAD DUE TO BEING ON THE WEST SIDE OF THE HOUSE AND BEING EXPOSED TO A GREAT DEAL OF SUNLIGHT. I NOTICED THE CONTROL PANEL ON THE 400btu GAS HEATER HAS THE CONTROL PANEL ON THE FRONT AS WELL. if PURCHASED WHAT CAN WE DO TO REDUCE THE ULTRIVIOLET SUN FROM DAMAGING THE CONTROL PANEL. tHANK YOU CURT
 Reply

A  Answered on 4/18/2018 by InyoPools Product Specialist Megan C.

The Universal H-Series Low NOx Heaters are equipped with Keypad Bezel Cover to protect the keypad. 
 Reply


?     Asked on 5/5/2018by Ronnie

What size pool is this heater good for???
 Reply

A  Answered on 5/5/2018 by InyoPools Product Specialist Lennox H.

Hi, Ronnie. This heater can be used to heat a pool/spa that is 10K-40K gallons. If your pool is larger you might need another unit depending on how fast you want the water heated.
 Reply


?     Asked on 5/6/2018by Jack

I'm opening the pool and starting up the Hayward heater, there is a crossover pipe between the inlet and outlet on the heater, is the crossover pipe in the open or closed position during normal operating function? I have it in the closed position but the heater keeps turning on and off. What is wrong? Thanks
 Reply

A  Answered on 5/6/2018 by InyoPools Product Specialist Lennox H.

Hi, Jack. The valve should be in the opening position. The water flow might be too much for the unit. 
 Reply


?     Asked on 5/21/2018by Bill

I currently have a pentair heater that is at least 20+ years old that I am replacing. (1) will this heater work with my Easy Touch Automation Remote? (2) there is a 3/4 inch gas line running about 85 feet from my meter to the current heater. Will that work with this?
 Reply

A  Answered on 5/24/2018 by InyoPools Product Specialist Lennox H.

Hi, Bill. This heater will work with an EasyTouch Automation Remote 2-Wire. The gas connection at the heater is 3/4", this unit will only work with 3/4" gas line if you have a High-Pressure, 2-Stage application. 
 Reply


?     Asked on 6/13/2018by Inyo Visitor

How do you turn the heater off?
 Reply

A  Answered on 6/13/2018 by InyoPools Product Specialist Lennox H.

Hi. You can turn off the heater from the power source, the breaker. 
 Reply


?     Asked on 6/17/2018by Roy

I have a pentair 400,000 btu heater now however the water lines come in from the left side of the heater. Can this heater be retro fit so i don't have to re route existing plumbing?
 Reply

A  Answered on 6/20/2018 by InyoPools Product Specialist Joe S.

Yes, this unit will allow you to rotate the unit. There will be a How To: Rotate UHS Heat Exchanger in the manual. 
 Reply


?     Asked on 11/6/2018by Gershon A Goldman

For a three wire remote connection to the Hayward Pro Logic board, where does the third wire, (spa) attach?
 Reply

A  Answered on 11/9/2018 by InyoPools Product Specialist Lennox H.

Hi, Gershon. The 3-Wire is for COM, POOL, and SPA. 
 Reply


?     Asked on 1/6/2019by Edwin Lee Ballard

Does the burner modulate or is it on/off only?
 Reply

A  Answered on 1/10/2019 by InyoPools Product Specialist Michelle B.

Hello, This will only be on and off.
 Reply


?     Asked on 2/7/2019by Gina

Is there a difference between the Hayward H400K and the H400FDN? If so, what are the differences, as well as the difference in price? thank you!
 Reply

A  Answered on 2/8/2019 by InyoPools Product Specialist Michelle B.

Hello, There is no difference between the two.
 Reply


?     Asked on 3/11/2019by Rosie

Can you turn this pool heater on remotely via your Smart Phone. I have an Apple phone?
 Reply

A  Answered on 3/12/2019 by InyoPools Product Specialist Michelle B.

Hello, Unfortunately, this unit does not have remote capabilities.
 Reply


?     Asked on 3/13/2019by Tim

How much does it cost to replace the fuse board on this heater?
 Reply

A  Answered on 3/13/2019 by InyoPools Product Specialist Lennox H.

Hi, Tim. The Field Wiring Panel UHSLN - FDXLICB1930 is available, click the link to view availability and cost.
 Reply


?     Asked on 4/21/2019by Pete Kamper

I'm looking at the Hayward N G Heaters. The 400,000 BTU and the 500,000 BTU The 400,000 has a shield over the control panel.Does the 500,000 also have this shield? Thank You
 Reply

A  Answered on 4/25/2019 by InyoPools Product Specialist Lennox H.

Hi, Pete. All of the Universal H-Series Low NOx Heaters will include a Keypad Cover Kit - FDXLKPC1930
 Reply


?     Asked on 5/20/2019by Sarah

Can this heater be installed below pool water level? Also how long is the 120 power cord? Thank you in advance.
 Reply

A  Answered on 10/15/2019 by InyoPools Product Specialist Steve M.

Sarah, we apologize for the inconvenience, however, we have been unable to obtain an answer from the manufacturer to your question. We suggest trying to give them a call and speak to them directly regarding this issue. Hayward can be reached by calling 800.429.9273.
 Reply


?     Asked on 5/28/2019by Sarah

Can this heater be placed below the pool level. And what do I have to do.. is it just change the water flow?
 Reply

A  Answered on 6/11/2019 by Industry Professional

This heater is not designed to be used below pool level
 Reply


?     Asked on 6/11/2019by Paul Gilly

Hi, I have a Hayward H400 heater installed in 2007. It has been taking long to "click" on & would stay on for about 6-7 minutes then shut off with the IF code. Any suggestions? thank you, Paul
 Reply

A  Answered on 7/9/2019 by InyoPools Product Specialist Joe S.

That would be an Ignition failure error. If the control exceeds the maximum number of ignition retries or recycles the heater will shut down and go into lockout. Automatic reset is 60 minutes.
 Reply

  • Commented on 7/10/2019 by Product Owner

    Hi Joe, I did change out the ignition piece & the problem was corrected--Thank You!
     Reply


?     Asked on 7/31/2019by HARMAN FRIEDMAN

I currently have the Haywood 400.000 btu unit, it appears that the 500,000 btu unit is the same but stronger and heats quicker, are they interchangeable? will there be any difficulty with the exsisting pipes or anything else?
 Reply

A  Answered on 7/31/2019 by InyoPools Product Specialist Joe S.

Good afternoon, The PVC for the water and wiring would match. The Gas line would be the variable that would need to be addressed by the installer. It would depend on the run from the meter to the heater.
 Reply


?     Asked on 8/3/2019by ramanbhai patel

my heater do not get ignite and display bd and fan don't run also
 Reply

A  Answered on 8/6/2019 by InyoPools Product Specialist Joe S.

Good afternoon, the BD error code would be for a BD Bad board or secondary high voltage fault. You would need to contact a service company.
 Reply


?     Asked on 9/13/2019by Kelley Weems

How many gallons is this heater for Universal H-Series Low NOx Heater 400K BTU - NG - W3H400FDN
 Reply

A  Answered on 9/19/2019 by InyoPools Product Specialist Megan C.

Hello,Please see our Sizing Your Pool Heater http://www.inyopools.com/Blog/sizing-your-pool-heater/ for details. 
 Reply


?     Asked on 10/5/2019by Inyo Visitor

Can I use this heater with a Jandy AquaLink RS system
 Reply

A  Answered on 10/6/2019 by InyoPools Product Specialist Lennox H.

Hi. Yes, this heater can be used with a Jandy AquaLink RS System. 
 Reply


?     Asked on 11/2/2019by Lyn

What is the efficiency of this heater?
 Reply

A  Answered on 11/4/2019 by InyoPools Product Specialist Lennox H.

Hi, Lyn. This unit is rated at 84% efficiency. 
 Reply


?     Asked on 11/18/2019by Dan

Will this heater replace my 7 year old Hayward H400FDN without having to do any extra plumbing? Will everything match up with the older version?
 Reply

A  Answered on 11/19/2019 by Industry Professional

Yes, both models will match up.
 Reply


?     Asked on 12/8/2019by James Watson

Have a 16k gal pool with spa all ungrounded. What natural gas heater is Best?
 Reply

A  Answered on 12/9/2019 by InyoPools Product Specialist Steve M.

James, the Universal H-Series Low NOx Heater 400K BTU - NG - W3H400FDN would be a little overkill for your 16,000-gallon pool. You can heat the water efficiently with 250k BTU unit. As far as quality, in my opinion, Hayward makes the best product.   
 Reply


?     Asked on 4/19/2020by PJ

I have a 7500 gallon spool. Need a new heater to replace a Sta Rite 400,000 but nat gas. Looking at Hayward...recommendation?
 Reply

A  Answered on 11/6/2020 by InyoPools Product Specialist Hector F.

Hi PJ, this Hayward H-Series Universal pool heater is a good replacement model for a Sta-Rite 400k BTU NG residential pool heater.  
 Reply


?     Asked on 5/11/2020by John A Taylor

I currently have a Laars LX model number LX400N will this heater match up plumbing wise and have same BTU?
 Reply

A  Answered on 5/11/2020 by InyoPools Product Specialist Patrick P.

Hi John, this is the heater that we suggest as a replacement for the LX400N however the plumbing ports are not in the exact same spot as your LX400N so there will be a little re-plumbing. We are not aware of a heater that has the same plumbing ports as your old LX400N heater.
 Reply

  • Commented on 5/11/2020 by Product Owner

    Hayward vs Raypak 400K what is better? If I convert to saltwater later down the road are both compatable?
     Reply

    • Commented on 5/11/2020 by InyoPools Product Specialist Patrick P.

      Hi John, I would suggest RayPak as it is a solid unit and that is all Raypak does is heaters. Finally the price of Raypak is better than Hayward. We would suggest this Raypak 406,000 BTU with CuproNickel Heat Exchanger if you are going to go with salt.
       Reply


?     Asked on 6/2/2020by tom weatherford

Shipping time to 77301 for 400000 btu hayward propoane pool heater
 Reply

A  Answered on 6/10/2020 by InyoPools Product Specialist Hector F.

Unfortunately, these heaters are not in stock and the average special order lead time is about 2-3 weeks unless the manufacturer is shut down due to the pandemic. 
 Reply


?     Asked on 6/2/2020by Aram

Is this unit could be work with LPG instead of NG?
 Reply

A  Answered on 6/2/2020 by InyoPools Product Specialist Patrick P.

Hi Aram, this particular unit will not work with LP but we do carry this Hayward 400K LP Heater which does work with LP
 Reply


?     Asked on 6/12/2020by Lyle

What is the amp draw at 120volts
 Reply

A  Answered on 6/12/2020 by InyoPools Product Specialist Lennox H.

Hi, Lyle. These units draw 5.5 amps and will require a 15 amp breaker.
 Reply


?     Asked on 10/8/2020by Joe

Hi, my plumbing is under 4feet high deck can I install a heater close to the filter under the deck?
 Reply

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

Hello Joe, thank you for contacting INYO POOLS. For install questions please review SERVICE & INSTALLATION MANUAL from page 27 and on.
 Reply


?     Asked on 11/28/2020by Orestes

Hey I’m replacing my Jandy lite 2 4000,000BTU gas heater. Is the H-series compatible? Will it work with the acualink system?
 Reply

A  Answered on 12/22/2020 by InyoPools Product Specialist Joe S.

Hello Orestes , yes you could replace the Jandy unit with the Universal H-Series Low NOx Heater 400K BTU - Natural Gas - W3H400FDN. Remote control connection: The heater is equipped for connection to an external 2-wire remote thermostat or a 3-wire remote switch. A 2-wire thermostat has its own temperature sensor for regulating water temperature. A 3- wire remote switch allows the “POOL” or “SPA” models to be remotely selected. Connect remote wiring to the terminal block located in the lower compartment inside the junction box (see Figure 22). The heater has 2 junction boxes (one on each side of the heater). Only one junction box should be used for remote wiring. Do not remove the wires connected to the remote connection terminal block. Remote wiring must be run in a separate conduit. Use 22 AWG wire for runs less than 30 feet. Use 20 AWG wire for runs over 30 feet. The maximum allowable run is 200 feet.
 Reply


?     Asked on 1/22/2021by Matt Murphy

What is the difference between the Hayward H400FDN and W3H400FDN for Natural Gas. Is this the same model, size dimensions, etc. My pool service technician has recommended the H400FDN as a replacement, but I am also seeing the W3H400FDN model too. I assume its the same model, size dimension, etc. Matt
 Reply

A  Answered on 1/22/2021 by InyoPools Product Specialist Joe S.

Hello Matt, they would be the same item. The W3 would represent a serial number and model number for a unit that is sold online.
 Reply


?     Asked on 4/27/2021by Joe Chadwick

Hello there quick question what is the difference between the W3H400FDN and the H400FDN ? and if I order this can I get expedited shipping to Mass??
 Reply

A  Answered on 4/28/2021 by InyoPools Product Specialist Matt S.

The H400FDN and the W3H400FDN are the exact same heater; the W3 prefix just denotes a unit that is sold through an online dealer like us.
 Reply


?     Asked on 8/10/2021by J Bailey

Does this model replace all older Hayward H400 models, or only certain ones? In my case, I have an H400ED2. Would the form factor and controls match up with my current installation?
 Reply

A  Answered on 1/14/2022 by InyoPools Product Specialist Joe S.

Good day, yes this would be a good replacement option for that unit. You will need to make modifications to the pipes and gas line.
 Reply


?     Asked on 5/24/2022by James R Amestoy

What is the use rate for gas compared to the use rate for propane
 Reply

A  Answered on 5/24/2022 by InyoPools Product Specialist Craig C.

Hello James.  One cubic foot of propane = 2516 BTUs compared to one cubic foot of natural gas = 1030BTUs.  Propane delivers more BTUs (per gallon or cubic foot) and burns less volume per hour than natural gas by a factor of approx. two-to-one.  
 Reply