I recently bought a house with an existing system. As far as I can tell it has 11 zones with 4 heads to a zone. I have opened each zone manualy with no problems. The water pressure seems to be fine, but when I set the system from the control panels (2) nothing happens. I have replaced both fuses in the panels and have checked that the power supply was working. The system is a watermaster model 57116. Please help.