Problem #1 with the lights is one that's a real head scratcher. I got nuthin' except maybe bored poltergeists.
Could #2 with the fan be caused by whatever you're using to determine the heat level failing open or closed to always indicate a high heat condition? That would explain the fan turning back on all the time since the Ocelot would always see high heat as true.
For #3 you might try replacing or swapping the solenoids for zones 2 & 3 with others as I've had those fail in the past or maybe the 24VAC power supply for the solenoids is failing or there's a shorted wire to the solenoids.
Thanks for the suggestions.
All I can think of on problem 1 is some sort of intermittent noise source or powerline glitches. The XTBM-Pro only gives the current noise level, which is zero. But several weeks ago I did detect a high noise level that disappeared as breakers were tripped, but it didn't resume when that breaker was switched back on.
My idea on problem 2 is similar to yours. There is a thermister in the garage that the Ocelot uses to calculate temperature. I have to pick through the code to see what might be causing the problem. I wrote that code two decades ago, and it has worked fine until just a few days ago. Maybe all it needs is a refresh.
I've had solenoids go bad before, but they are working fine. I can manually switch them on and off through the Rain8 with a 4-button X10 wall controller. If it was a stuck valve, the next zone would have come on, but it didn't. Similarly, the 24VAC is fine.
I can understand one unit acting up after a couple of decades due to a soft programmed bit, but why are three different controllers misbehaving the same way? (Zone 3 stuck on again this morning.) The only idea I have is that somehow random X10 traffic is confusing the Rain8 while it is proceeding through its sequence. But it had worked fine for almost 2 decades. Why now?
As a test I'm going to modify a XTB-523 to only accept the housecode that controls the Rain8. If that fails, I guess I'll have to move the timer function into the Ocelot, and only use the Rain8 as a multi-channel X10 relay.
I considered a commercial smart irrigation controller, but we have the unique situation that there are just a couple of inches of soil on top of a lava flow for our 20' x 40' "lawn". So that dries out very quickly in the summer when days are often over 110F. The Ocelot runs periodic short cycles depending on the temperature to keep everything alive. And of course we have to be compliant with water restrictions during the summer months.
Jeff