new to the forum, had some issues with my hayward h400idl and a quick google search took me here. we've had a hayward h400idl for about 8 years now, and this summer it stopped working.
after inspecting the unit, i discovered that the ignitor was broken (the end had somehow broken off inside the heater). i figured that was the problem, but after replacing it, the burners still won't fire up. what happens is i'll start up the heater, the pilot light will come on (i can see the orange glow through the small glass hole), and then i can hear the machine click on and i can smell the natural gas begin to flow. after a couple of seconds the machine clicks off, the gas smell dissipates, and the pilot light turns off (orange glow disappears). this cycle happens three times i believe, and then i get the "IF" ignition failure code on my front panel.
it was suggested that my flame sensor may be the problem, so i took it out and cleaned it with some emery cloth. when i put it back in, same issue: no ignition. i ordered a replacement flame sensor off amazon which came today, put it in, and still no ignition.
any help/suggestions would be great.