Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 3 of 3

Thread: Hayward H400IDL2 pool heater with service code SF

  1. Back To Top    #1

    Hayward H400IDL2 pool heater with service code SF

    I have a Hayward H400IDL2 pool heater that has an error code of SF. I believe this is a bad temperature sensor. From what I have been able to figure out, there are 2 of these sensors, 1 for high temp & 1 for low temp. How can I figure out which one is bad? Is there some type of test to them that can be done, ex: resistance, voltage while running, etc. I have some electronics & electrical experience & have a DVM to check circuit problems. Thanks.
    15x34 in ground, 16.5K gallons, Emerald Isle pebble finishing
    Pentair IntelliFlow VS-3050 pump
    Pentair Quad D.E. filter
    Pentair IntelliChlor
    Pentair IntelliBrite 5g LED light
    Pentair Great White Vacuum cleaner

  2. Back To Top    #2

    Re: Hayward H400IDL2 pool heater with service code SF

    SF (Sensor Failure) indicates that the temperature sensor (thermistor) is not getting good data to the circuit board. Check the wiring. If the wiring is Ok and the error persists, replace the sensor. There is only one temperature sensor (IDXLTER1930). There are two Hi-limit sensors, but they are not involved. ... r1930.html

    Here is Ignition Board (aka Integrated Control Board or circuit board) (IDXL2ICB1931) (Heaters built after 9/20/04)

    You can see the three prong connection site for the thermistor. ... ze%3dlarge ... mage/3424/ ... _171/3a/5/ ... %20NOx.pdf

    I'm not sure, but I think that you can test the thermistor according to this chart. I think that that thermistor might have two thermistors inside for extra reliability. It compares readings and throws an error code if the readings don't match or if the readings are "out-of-bounds". ... -chart.pdf

    I think that if you test resistance from black to one of the reds, the resistance in ohms should match the temperature of the thermistor. And, the resistance from black to the other red should match the first result.
    Support the site

    Trouble Free Pool is a free resource. The people who answer questions are volunteers. If you find the site to be a good resource, please consider making a donation to help support the site. Thanks.

  3. Back To Top    #3

    Join Date
    May 2014

    Re: Hayward H400IDL2 pool heater with service code SF

    I have a Hayward H250. This solution worked for me as well. turns out that the copper pipe to the water pressure switch was all corroded and it ended up leaking water which corroded the wiring of the thermistor. So I had to replace both the copper piping (Which comes with the pressure assembly) so replace that as well and the thermistor.
    Biggest issue is that no manual tells you that the thermistor and the copper piping are only accessible if you take the 2 panels off on the right side (upper and lower) 7 screws total that are around the piping. They are in the manifold but are not exposed. The thermistor is kind of hidden but once you take those off, easy as pie.
    No videos show this. Someone should make one. Total repair was about $180. Pool guy would have charged $500.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts