The unit was shutting down after the three cycle attempts. In checking the connections and cleaning with an eraser, and looking at the igniter/sensor, I decided to go for the inexpensive replacement of the igniter/sensor. That was the fix.
The probe did appear to have a form of corrosion on it and the wire lead into the ceramic cylinder was loose.
$118 per hour service fee w/o parts
or try a $50 replacement part
The probe is the most common failure to give that symptom. Since they are subjected to the heat of the flame all of the time when water is being heated, over time they do oxidize and eventually fail. The probe has two functions, it not only supplies the spark when a high voltage is applied, but between the spark attempts, it then monitors for a tiny return voltage that tells the circuit board if there flame is burning. If the sensor fails to detect the heat of the burning propane, then it tries three times and then shuts off, for safety.
Had a problem like that with my furnace.. In my case originally the dang thing did not light,, Well I fixed that (ignition points were too far apart, Turns out this is fairly common in furnaces and not just RV furnaces, I have dealt with this issue two times, both times same problem, the other one was in a sticks and bricks).
Then it worked fine for a bit but went into the Try 3 times, lighting every time, and shut down mode.
Well, hooked up ye-old-high-impedance volt meter to the probe and simulated burner operation.. GOOD result.
Put in a new control board (From Dinosaur boards) and .. Well let's just say the next cold night I had a real warm feeling.
about 100 dollars for the board (That includes part of the S&H from American RV) I won't even try to estimate how much labor I put into it but once I identified the problem. 5 minutes covered the actual replacement.
Or.. I spent longer on -line ordering it then I did installing it.
Nothin adds excitment like something that is none of your business
Kenwood TS-2000 housed in a 2005 Damon Intruder 377