My UAD300 water alarm system is alarming with no visible water being present.

Remember that this system was designed to be very sensitive, so the smallest amount of moisture will trip the alarm. Most problems experienced with this system are battery related. The battery used should measure 12 Volts using a simple volt meter. It is helpful sometimes to clean the ends of a new battery with rubbing alcohol or even sanding them very lightly with a very fine sand paper. Spinning the battery in the holder can also help it seat properly. When a good battery is installed the console should alarm each time that you touch the two pin sockets on the transmitter. Now insert the water sensor plug into the pin jacks on the transmitter and touch the silver water sensor pad which should again trigger the console. If the console alarms immediately upon plugging the senor in you may have oxidation built up on the silver sensor pad. Carefully clean the silver pad with rubbing alcohol and dry. Occasionally oxidation has built up around the white striped wire solder connection on the pad (this is on the side that connects the “uncle alberts water alarm” silver letters to the wire). This oxidation may be easily removed by carefully scraping with a fine screwdriver. Once clean the console should alarm reliably each time that you touch the pad across the foil connections.