Hayward H400 pool heater

I have a Hayward H400 series pool heater that cycles through startup but will not ignite and is showing an IF code once lockout has occurred .   This is a list of items I have already completed with not results.

Cleaned heater, replaced frayed wires, replaced ignition components,  replaced circuit board, yes I have propane and the valve is on.   I do smell the propane when attempting to start and the ignition switch does get hot.  Any ideas

Hi Vinny - same problem here - had the pool guy come out and he was not a heater expert.  He did get the valve off for me which I just replaced today and no joy.  I am at my wits end with this thing.  Do you get anywhere?

This is my second Hayward Heater in 14 years.   The first time it was pretty much the same story,  not experienced tech,  changed gas valve and circuit board, no results.   Pool people were clueless.  After totally annoyance I reviewed a library on YouTube.   It turns out that the tubes at the bottom of the heater were totally rusted through.   These tubes catches the gas when first coming into the unit to ignite.

This time out it was spiders inside the gas valve of the unit.  In particular,  there a white plug on the top right side of the gas valve,   Take a can of air and insert where the plug was and discharge air for about 10 seconds.   Spray how CW40.  Plug back on ,  turn gas back,  pushed button BINGO

Thanks for the reply.  I will pull the burners out today as that could be the problem.  We did have the whole assembly off and I blew everything out so we will see.  Thanks again and happy swimming.