Abstract: An irrigation system valve controller which provides for alternating operation of two conductive output paths from a single energizing input source. The valve controller allows adding new valves to an existing automatic sprinkler system without having to route additional wire between the new valves and the existing system controller, and provides independent control of each valve using a single pair of input power leads from the existing controller.

Abstract: A circuit isolator apparatus for use with pump or master valve circuits having a plurality of controllers connected thereto. One isolator apparatus is used in association with each controller. The isolator apparatus includes a pair of relays which allow only one controller to access the pump or valve circuit at a time to prevent feedback between controllers and damage to controllers due to incorrect phasing.

Abstract: A device for expanding the number of stations controlled by an existing irrigation controller or the like, or which can be operated as a stand-alone irrigation controller. The device (10) includes a control processor (12) which sequentially activates one or more control lines (66) for a predetermined period of time, the time periods being independently set for each control line. The timing cycle of the device (10) can be initiated manually or from a station control line (60) of an existing master controller (50). Activation by a master controller occurs after the station control line to which the device is connected completes its timed cycle according to the master controller. One or more of the devices can be cascaded to provide unlimited expansion capability.

Abstract: A retrofit mechanism for automatic lawn sprinkler systems. An electrical latching switch which when successively energized switches energizing power to one of two or more conductive paths is housed in a waterproof casing. The retrofit mechanism is installed near an existing electrically operated control valve in an automatic lawn sprinkler control system. The latching switch is wired to the system controller by the wire originally connected to the existing valve. The existing valve and one or more new valves are connected to the conductive paths of the retrofit mechanism. Thus, new valves are added to the automatic sprinkler system without running wiring and conduit between the new valves and the existing controller.