How do I fix this sprinkler head?

[CottonEyedHorn]

I've had this same sprinkler head "repaired" twice by the same guy, who, although cheap, is still apparently over priced. This head is on the first zone, and without fail, doesn't come on fully when that zone comes on. It looks exactly like the one in the diagram below. The riser comes all the way up, but I get a lot of water coming from where the wiper seal line is pointing to. If I pull up just slightly on the riser, it works fine. How do I fix this? Should I just replace the whole unit

Oh, and in case someone mentions "check the valves", that'd be nice if I could find the freakin' valve box

 

[NickDanger]

Pull it up and spray it with some silicone spray if you don't want to spend the $5 to replace it. If you do decide to replace it, and you buy the same brand, you don't need to replace the entire head (you'll have to buy an entire head). Just unscrew the cap and replace everything except the body. There is no reason NOT to replace the body except you will probably be glad if you dig out around it to keep crap from falling in the line and clogging a screen somewhere in the line. Usually the last head. Most likely, your guy just replaced a screen for which he should have been paid about 7 cents in parts, $1.00 in labor and whatever a service call costs. Of course, the subsequent repair ought to be a warranty item.

You probably have had some grit in there that keeps the riser from rising smoothly. The alternative is that you just don't have enough pressure in your line, but that usually manifests itself farther down the line.

I have to wonder though. If you don't know where the valve is, how do you know it's the first head on the line? It doesn't necessarily follow from the fact that the head is closest to the house.

 

[NickDanger]

Sorry. Reread and you just said it was first zone. If it is the last head on the line, you might benefit from reducing from 3/4" down to 1/2".

 

[CottonEyedHorn]

Thanks Nick. I think I may just end up replacing the whole unit, seems easier that way.

 

[NickDanger]

If you do, you will probably end up with a clogged screen somewhere. Just run the system for a while and see if any of the heads weaken. It will eventually end up at the end of the line. Or, you might not have any clog at all.