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I have a system with a Hays brass solenoid 110v main control valve running into a 5 zone Fimco Cycla-matic (metal) zone controller. The diaphragm in the Hays valve has failed and the system will not function. I cannot find any reference to this type of Hays valve to replace the diaphragm. My options are to replace the valve with a new plastic control valve or brass. I was able to get a 1 1/2"plastic valve locally and would like to replace it with this. The pipes are all about 30 years old and appear to be steel what would be the easiest way to replace the valve if I want to replace all the pipe fron the main supply to the Fimco Cycla-matic controller. Do I need some type of anti-siphon valve in place? Does anybody know where I could just get a replacement diaphragm? Thanks for your help.