PiggyBack is a hybrid 4-station timer used to increase the capacity of an existing controller. You can upgrade an 8-station clock to a 12, or a 12 to a 16, etc. PiggyBack is especially useful when adding more valves with DOUBLER or DOUBLER2 where all the stations in your existing controller are already in use. Adding another controller just complicates your life every time the weather changes. PiggyBack turns on after the controller completes it's cycle so there are no start times or programs to set.
A trigger wire connects PiggyBack to a station on the controller. when that station turns on, PiggyBack is alerted through the trigger wire and when it shuts off, PiggyBack begins watering. PiggyBack always follows the station it is connected to. You can add stations to a lawn program by connecting by connecting the trigger wire to the last lawn station or add to a shrub program by connecting a PiggyBack to the last shrub station. You can even do both! To shorten total watering time PiggyBack's trigger wire can be connected to the first station to water drip systems while the controller operates the sprinklers. To add more than 4 stations on the same program connect the trigger wire of a second PiggyBack to the last station of the first PiggyBack module.
Each station of the PiggyBack has time settings of one minute to 4 hours. A manual Start/Advance button makes testing and flushing sprinklers easier. PiggyBack can be used without a controller by connecting to a 24VAC transformer. With a 2 Amp fuse and optically isolated outputs on each station, PiggyBack is one of the most reliable parts of any sprinkler system.