Stanley, can you find and get into your irrigation valve box? Do you know what a manifold is?
If you can, then there are only a few items that could be there. Backflow prevention assemblies, shut off valves, filters, and master valves.
If you have a manifold, then you would have a manifold, irrigation valve(s) and the wiring. The valve is the item that the wiring is connected to. An irrigation valve can be in a variety of shapes. www.sprinklerwarehouse.com/Sprinkler-System-Irrigation-Valves-s/36.htm
If you have a weeping valve, it is probably caused by either debris in the valve, causing the diaphragm to not seal properly, or a faulty diaphragm.
You can try to open up the valve and see if there is anything in the valve. Shut the water off first. Sand, dirt or small pebbles can also cause the diaphragm to not seal, so the debris can be very small. If your diaphragm is faulty, you can replace it.
Normally when I go to a service call with a weeping valve, I will do an inspection and a quick clean out. Other than that, it's less expensive for the client if I just replace the guts and upper portion of the valve. With the cost of the valve, and labor rates, it's less for the client than taking expensive time searching around for a diagnosis to repair a cheap part.
If you replace the diaphragm or the valve guts, the valve parts will have to be from the exact same make and model as you have in the ground now.
Mick
This post has been edited 1 times, last edit by "Fireguy97" (Aug 24th 2010, 1:13pm)