Question about Hayward HEATER THERMISTOR - IDXLTER1930

1 Answer

The SF signal on my Hayward GAs Heater H400FD series needs to be replaced. I have the part but can not seem to be able to find it inside the unit for replacement. The diagrams in the manual are not sufficient and I can not see a similar part.

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 990 Answers

Remove the sheet metal covers (top and bottom) on the side of the heater where the pipes come into the heater. It screws into the header just behind the cover. Then just follow the wires back to the front of the heater and find where they plug in to replace the unit. This will be behind the top cover on the front.

Posted on Sep 04, 2010


1 Suggested Answer

  • 2 Answers

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

A 6ya expert can help you resolve that 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.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


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



Related Questions:

1 Answer

What should I do if Hayward pool heater is reading error code SF??

The code is SF. This is a teemperature sensor failure. Check the wiring on the electroniics bord and confirm its not damaged and that it is securly plugged in. If all is good than the temperature sensor will need placing.m either a gas fitter or swimming pool reepair center will help with this is your not comfortable replacing it

Jul 15, 2013 | Pool & Spa

1 Answer

Where is the temp sensor on a Hayward H300 ED2 pool heater

take off top there is a copper wired unit going into header and wire to the board

Sep 18, 2012 | Hayward H-series Electronic Gas Pool...

1 Answer

Hayward H400FD. Can't adjust temperature.

need new display board also check if connected to a system disconnect and try alone

Jan 28, 2012 | Hayward H400FDN Low NOx Natural Gas Pool...

1 Answer

I have a new Hayward H400FD ! How much Propane does it need in one hour of heating ??

A 100k btus burns roughly 1 gallon of propane per hour. A400k btu heater burns approximately 4 gallons (actual is somewhere between 4 - 4.18 gallons per hour.) That's assuming that the heateris running non stop during this time period.


I know your question was fairly simple and disp notrequire a whole lot of information but we appreciate you giving us somefeedback!


The Ugly Pool Guy 

Dec 11, 2010 | Hayward H Series Pool & Spa Heater 400k...

1 Answer

Haywood heater has code sf what does that mean

SF is a thermistor error. Once the heater cools down it should reset itself. If not, call a service tech.

Jul 03, 2010 | Hayward H Series Pool & Spa Heater 400k...

1 Answer

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.


May 31, 2010 | Hayward 400FDP Universal Series Low Nox...

1 Answer

SF error


I think you must be mistaken about your heater being a millivolt heater. They have not mfg these heaters for some time. And they probably would not give you an SF error. If you have an SF error, it is a newer model with a digital board. Millivolts usually have two analog temperature dials on them and no digital readouts. That should be the part. HTH

May 20, 2010 | Hayward H-Series 200k BTU Millivolt Heater...

1 Answer

Hayward H300 Spa Heater will not fire up

try to replace the thermo sensor it is located on the left side of tghe unit and has 3 wires running to it.

Mar 05, 2009 | Hayward H Series Pool & Spa Heater 400k...

Not finding what you are looking for?

Related Topics:

455 people viewed this question

Ask a Question

Usually answered in minutes!

Top Hayward Pool & Spa Experts

Jay Finke
Jay Finke

Level 3 Expert

1383 Answers

Craig Butler
Craig Butler

Level 3 Expert

1723 Answers

Charles T Nevin
Charles T Nevin

Level 3 Expert

4070 Answers

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

Answer questions

Manuals & User Guides