Hi Ray,
I have built the open sprinkler v1.4u and I did have a bit of trouble with the unit starting a watering zone then after about 15 seconds, the unit would re-boot and start from scratch, I found that because I have a relay (taking about 20mA at 24v) and it operated 4 master solenoids (most would only have one) and then a zone (2-8) would operate the particular watering zone solenoid, (each solenoid drags about 130ma ac at 24v) so the over all current would cause the PTC fuse (thermister WH60 075)) to heat and go high resistant as its suppose to do and therefore at approx 17v AC being supplied (at the point after the PTC) then would reboot the unit, all stations would be switch off and it all recovered, so what I did for a fix was to put a 1amp fuse instead, I know that if a S/C was to happen, the triac would get red in the face and probably be destroid (which I think are good for 600-800mA), but could be food for thought, I may get a lower rated one and put in each triac Cct,
cheers
Gazza