Question about Hayward Pool Products Hayward 400k Ng H Series Spa & Pool Heater

1 Answer

Problem with my H400 IDL natural gas electronic ignition heater

I have a Hayward H400 IDL natural gas electronic ignition heater. My heater is about 5 yeras old and I have used it 5 times. I opened the pool this year and followed the directions to fire up the heater and it didn't work. It would start its cycle and I would hear a click then it would catch and I would feel heat from the vent and then after 3 seconds it shuts off. I had my gas company come out and they thought it was a delivery issue. I wasn't sure why now since it had worked all these years but they changed an old regulator and I recieved a greater gas flow but within the tolerance of gas supply needed to operate the unit. They checked all the limits, gas valves, cleaned the flame sensor, burners, cleaned alll the gas pipes made sure there were no obstructions and no cob webs. In the end the diagnosis was bad module controller or flame sensor or both. What do you think. These parts are expensive and I was told I could repalce them myself. help.

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.


    An expert that got 10 achievements.

  • Hayward Pool... Master
  • 8,694 Answers

Bad flame sensor

Posted on Oct 24, 2017


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

  • 14 Answers

SOURCE: Hauward H400 heater won't turn on

check pressure switch operation most heaters will not operate without sufficient water flow/pressure. You can use a multimeter to troubleshoot the wiring using the schematic. If its induced draft milivolt ignition verify there is suffiecient gas flow to the unit

Posted on May 26, 2009

  • 15 Answers

SOURCE: Hayward H Series 400,000 BTU Pool Heater Won't Ignite

You can not manually light it. Open the front cover look for the gas nozzles brass looking on a tube. on the right side you will see a wire going to a sensor above the next to last burner take the nozzle out for that burner. 7/16 wrench unsrcew the nozzle and see if it is clogged. use something soft to push it out. Spiders love to lay eggs in these. Spray with WD40 and reassemble should work now

Best of luck

Posted on Jun 23, 2009

  • 331 Answers

SOURCE: finned tubes get too hot all thermostats and controls chech out o

Sounds like you might have an elevation vs gas burn issue. If you are using a unit not designed for the elevation it is installed at, the unit can burn incorrectly causing the problem you are reporting. Hayward as well as other manufacturers make units to operate from sea level up to about 2000-3000 foot and units designed for higher elevation. It has to do with burn rates and proper gas mixture with oxygen. higher elevation has less oxygen and thus need different size gas orifices. It also is important to make sure you are using a Natural Gas unit with Nat Gas and not propane. Propane burns much hotter and requires smaller orifices. This can also cause premature burn out. Check with Hayward to determine your unit qualifications vs location of installation

Posted on Apr 14, 2010

  • 1378 Answers

SOURCE: my plumber needs manual for Hayward #H400 FDP

The P at the end stans for propane...the manual found here is for the H400FD series natural gas or propane.


Posted on May 31, 2010

  • 78 Answers

SOURCE: hayward H400 error code bo

This error means "Bypass Operation". On the back of the control module there are some "dip switches". They have an on or off position. Check switch number 2. Make sure it is in the "off" position. The "on" position is for a remote thermostat.

Posted on Jun 29, 2010

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Replace igniter on h400

Open the main door, locate the 2 white fabric coated wires, they go down towards the base of the heater. This is your igniter, usually a 5/16 nut driver will be the tool you need to remove it.

Jul 04, 2014 | Hayward H-series Electronic Gas Pool...

1 Answer

IF error code when trying to start

Error IF is ignition failure.
Last page shows troubleshoot walk through ranging from low gas pressure to bad gas control valve to failed wiring etc

If you need further help, I’m available over the phone at

Oct 28, 2012 | Hayward H-series Electronic Gas Pool...

1 Answer

No LEDs on Hayward H400 ED1

if power to unit and transformer ok need display

Aug 03, 2012 | Hayward H Series Natural Gas Electronic...

1 Answer


The last I checked a kit was available for this conversion.
I recommendyou call the Hayward technical support at 908-355-7995and they might be able to help you figure this issue out. Ihope this helps.

Sep 17, 2011 | Hayward H-series Electronic Gas Pool...

1 Answer

Can an H150PI pool heater be converted from propane to natural gas

On this heater, the conversion may be a kit that replaces all the orifices. In any case if you call Hayward technical support they should be able to provide the correct solution. I hope this helps.

Jul 27, 2011 | Hayward H-series Electronic Gas Pool...

1 Answer

I have a hayward H400 serise propane heater. I replaced the gas valve. When it goes tot turn on it takes about a minute then starts clicking to ingnite the gas. SSoem time it lights but then goes out other...

0. Check the spark ignitor conection to the board
1. Check the water by-pass valve if you have it
2. Check your gas pressure. (5-7"wc for natural gas, 9-13"wc for propane gas)
3. Clean your filter for your water system or remove it and try again
4. Check the Hi-limits on your heater
5. Replace the thermostat

May 27, 2010 | Hayward H Series Pool & Spa Heater 400k...

4 Answers

Hayward H400 Pool heater will not stay lit

"IF" - Hayward Pool Heater Fails to Ignite: the most common reason for this problem is insufficient gas supply. The Hayward heater LED display will show a diagnostic fault code of "IF" which stands for Ignition Failure. Undetected gas pressure problems if not investigated properly may result in unnecessary replacement and servicing of your Hayward Pool Heater.

Jun 06, 2009 | Hayward H-series Electronic Gas Pool...

Not finding what you are looking for?
Hayward Pool Products Hayward 400k Ng H Series Spa & Pool Heater  Logo

Related Topics:

252 people viewed this question

Ask a Question

Usually answered in minutes!

Top Hayward Pool Products Pool & Spa Experts

Jay Finke
Jay Finke

Level 3 Expert

1384 Answers

ray gallant

Level 3 Expert

52135 Answers

Tom Chichester

Level 3 Expert

45139 Answers

Are you a Hayward Pool Products Pool and Spa Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides