Hayward Heater Woes

Hi all.  Hayward H400 heater 15 years old but seemingly in good condition.  Had several bouts with the display and control PCBs.  Current situation is new board and dislplay.  New Ignitor and new 5" Flame sensor.  Blower comes on, gas comes on and heat light comes on for about 3-5 secs and then shuts off. 3X and provides IF error code.  I pulled the ignitor and it gets energized and red hot.  I cleaned out all spider webs from orifices and I smell gas as it starts up.  I don’t here the whoosh of the flame up from the burners and it fails to light.  The valve regulator adjustment screw is all the way in which I believe is max flow for the valve.

Thoughts? Thank you for any advice!

Joe

Does your heater have a flame detector and have you checked to determine if its working properly. If no flame is detected gas flow is normally cut and 3 tries put you in fault mode.

Hi thanks for responding. - yes and I just changed it.  They recommended a 5" one over the 3 that it came with.  Very puzzling.  I just went out there in the dark.  I see through the site glass that the ignitor lights up brightly.  It injects gas for a few seconds but flame up doesn;t happen.  Maybe the burners are clogged?  Not sure how to take off the manifold.  Large coupling on the gas line that is very tight.