I recently purchased a home with an in ground pool. The pool is equipped with a Hayward H400 FDN gas heater. It is 4 years old. I was first getting a CE code. I replaced display board and it went away. Heater is firing up and after 1 minute of running it throws a HS Code and abruptly shuts off. I called Hayward tech and they told me to replace the temp sensor ( $47 ). I did that this morning. I am still getting the same code. I call back Hayward and the guy tells me if it is still throwing a HS code then the Integrated control board needs to be changed but suggest calling in a certified tech. I called a company and it is $130 to show up. I can get the integrated control board for $169. I am pretty handy and have no problem changing parts. I am leaning towards just changing board. Has anyone had and experience with the HS code for Hayward heaters. Any ideas or advice will be appreciated. Thanks in advance.