Originally Posted by Without A Drought
if the sensor is wired to the common in the field, you have a few options. if you can get to the sensor, remove the cap, or do whatever it takes to "untrip" the sensor (take the cap off, empty the catch cup, etc.). if you cannot get to it, you can buy and wire in a bypass switch. these are simple on/off switches that will close the open circuit the rain sensor made in the common wire. you can also strip a little bit of each wire where it comes down from the roof and twist the 2 wires together, which also closes the circuit. not the best practice, but it works in a pinch.
the hardest part of all of this is in the troubleshooting. ive spent many hours trying to track down a bad common before i remembered to check for a field wired rain sensor. but, that's the true measure of a good service tech. not how many heads you can change in a day, but how fast you can figure out what the problem is and how to fix it.
I went back yesterday and apparently the rain sensor had dried out and "untripped" itself. The system ran fine. Thanks for the tip about installing a bypass switch.
I certainly learned a lot on this service call when it comes to field wired sensors!!
I appreciate everyone's input and advice.