You say that "zones 4 and 5 ran at the same time. "

Most likely , your zone 4 valve is stuck, for whatever reason. When
your controller sent electricity to zone 5 it ran fine, but zone 4 was
still running because even after that valve power was cut off, the valve
itself is stuck and that is why you had to shut the water off.

Some folks can fix bad valves. Some valves have a replaceable diaphram,
some don't.

good luck !!


James