I saw two problems with our Ambient Falcon WS-8478 - the rain gauge stopped displaying rainfall amounts and the Outdoor Sensor array was showing a "low Battery" icon.
Pulled the mast down and clean up the sensor array/chassis outside and in, green soap and water then mopped it dry with paper towels.
There was 1/2 (!) a bug stopping up the Rain Collector funnel and I put in 3 replacement AA Batteries - Duracell AA24 Alkaline cells. The PWS has been in place since Jan/Feb 2019 so I'm seeing a year and a half, just about, from a set.