It had needed to be relocated from it's old position - and as part of reconnecting it, I though I'd test it as well.
Unfortunately, it didn't want to work in the new location. Rather than buy a new one, I thought I'd open it up and see what the problem could be.
They are quite simple devices ...
- a sensor, which consists of a number of fabric type discs stacked on a rod
- when the discs are exposed to water they expand
- which in turn presses a micro switch
I disassembled the unit - and tested the micro switch - which was all ok. This particular one has the three leads:
- one common
- one for a normally open circuit
- one for a normally closed circuit
And here finally is the result - the irrigation controller showing the rain symbol.