We recently bought a home that's about 30 years old. There are only 5 zones with a maximum of 3 sprinkler heads on each zone. Zones 1-4 work OK (plenty of pressure) and good rise and coverage from the popups. However zone 5 is driving me nuts. The pressure at the sprinkler heads is so low, that they just bubble. The valve seems to be working OK and turns on and off like it should. When I remove one or more of the sprinkler heads the water simply bubbles out of the tee. I use a 26VAC sprinkler controller transformer at the valve so I can test the zone without having to run back and forth to the controller.
The valves are Richdel 240 (did they get bought out by Irretrol?). I replaced the solenoids on all valves when I started refurbishing the system. All zones work OK but zone 5 had no pressure before or after the new solenoid. I have dismanteled zone 5 valve and checked the diaphram, spring, etc. All looks OK. I have started to dig up the pipe to see if there is a leak or broken pipe somewhere. Whoever originally installed the system used schedule 40 (white) PVC underground - not sure if this is a problem. I have dug up over half the zone down to the pipe and still have no visual indication of leak or broken pipe. Is it likely that a leak is the problem in this case? Could there be a blockage in the pipe before it gets to the tee that connects to the zone 5 grid? I will continue digging but getting a little discouraged and frustrated at not finding anything positive yet that could cause the problem. Is it more likely that a break would be close to one of the heads or at a tee? The pipe is at least 6-8 inches below the surface.
Also, is there a source for parts for the Richdel 240 valves?
Any suggestions, observations, or witchcraft, will be appreciated.
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Thanks,
Nils
Plano, Texas