hot water heater fault light on LP

Do you have reset buttons inside the wh

yes, two rubber reset buttons, neither will depress so I guess not tripped?

With 'two rubber reset buttons' you have a Suburban Brand (always nice to post brand/model cause they are different)

Left reset is for 120V AC electric element

Right side is for 12V DC---propane

Resets are for Hi temp t-stat (they trip at 170/180*F if normal fails to open at 130*F)

Fault light......
No DC power
Main flame fails to light

You get fault light immediately........but does it attempt to light and fails? (some have light come on until flame happens---then comes back on if flame fails)
If no spark/no flame then you have no DC power

DC power comes from DC Dist Panel (Fuse) goes to ON/OFF switch then to DC Junction Box (on back of WH tank) then to the set of t-stats then to circuit board for gas valve & spark.

Easiest place to check for DC is at set of t-stats
Remove reset cover
Right side RED wire to top t-stat....measure for 12V DC going in (No DC IN.....then junction box connection/bad switch/blown fuse)
Then RED wire at bottom t-stat..measure for 12V DC coming out (No DC OUT...then bad set of t-stats-------YES DC OUT then check connections at circuit board/dirty=loose etc)
That is IF connecting wore between top/bottom t-stats isn't burnt into

thank you for the detailed info!

I blew the burner out with compressed air, turned the LP wall switch on and went outside to listen and sure enough it fired up.

Thanks for the help!

There are basically 5 things that can make the LP FAULT light light.

1: LP issues (I assume you have LP and the tank valves are open but hey.. Got to ask). Also regulator issues (How does the stove work?)

2: Clogged gas jet.. There is an insect that likes to nest in gas jets.. They can clog from other things too

3: Flame sensor issues. Yes they can go bad

4 Ignition issues.. Often I find spark gaps too wide and considering I only work on my own and my parents... 75$ of the time I've found spark gaps too wide this is not a good "It's ok" rate. The water heater by the way was the other 25% The only on set right

5 Control board issues.. My OEM took at least 3 tries before it worked when cold

The Replacement COntrol board is much better.