Low Pressure on 2 heads

[drummonkey4jc]

I'm new to the world of irrigation etc, but have an annoying problem. My front yard has an underground sprinkler system with the pop up brass sprinkler heads. It comes straight from the main water line to the house. Right before the first sprinkler head, the line splits in two, one going north one south. On the south run, there are 8 heads. It is 3/4" pvc all the way down the line. The last 2 have terrible pressure, and just sort of squirt out maybe a foot-2 feet. The north run has 3 brass heads and one impact turning sprinkler and no problems. Is this just a "too many heads for one run" problem? I just planted grass seed and need to water, so I need to fix it soon. I didn't really notice the problem earlier since one of the sprinkler heads was completely buried, and I only found it when prepping the soil for the seed. Any thoughts? It may be a pipe dream(pun intended) but I'd love to not disturb the new seed too much I attached a diagram of the yard.

[FloridaOrange]

You might have a broken pipe for those last two heads.

Given your description it sounds as if you don't have a backflow preventer on your sprinkler system......I know you're not asking about it but if that's the case you really need one installed.

[upper]

Unscrew the bad heads off,then check for blockage.If you still have poor flow then Florida may be right.Or plug the other good heads and see if it helps the bad ones.What kind of valve do you have? Upper

[drummonkey4jc]

well in the process of moving the last head over to the other line, i learned it had a big hunk-o-gunk in it, so with that cleared out, moved to the other run, it works just fine. FYI there is a backflow preventer on it..just didn't know thats what it was called Thanks!

[FloridaOrange]

Glad you got it and you have the preventer. Upper was (obviously) correct, the last sprinkler head advice I gave weas a collapsed line - it was stuck in my head.