Abstract: A modular valve has a valve housing which defines a manifold interface having a normally open port, a normally closed port and a common port. A manifold block is mounted to the valve housing with its valve interface sealed against the manifold interface. The valve interface of the manifold block has first, second and third valve ports which lead to respective first, second and third mounting ports at a mounting interface of the manifold block. The first, second and third valve ports and the normally open normally closed and common ports are arranged to communicate with one another in either of two angularly spaced positions of the valve housing relative to the manifold block. In one position, the first valve port comunicates with the normally open port, the second valve port communicates with the normally closed port, and the third valve port communicates with the common port.