Is your system drawing from a resevor with a float valve? Does your system have check valves at the boom or in the mechanical room? Do you have dema valves controling your
soap supply? Sounds like design problem maybe. Presoak may be clearing out of your manifold when you turn on the rinse cycle, if its in line a distance from your wand it may take a few seconds to clear. If its in all bays and your drawing from a central tank for cold rinse might be but not likely. Probably just a dema valve with a bit of "stuff" under the seat. Hit it with a small hammer or disassemble, flush and clean. Have a great day! jjw
