Sprinkler won't work on one faucet, works fine on the other

[indifferent]

I have two outdoor faucets; one of which is installed after the whole house water pressure regulator. The other one is connected to the main pipe right before the water pressure regulator and this is the one that simply doesn't supply enough water to run a single rotary or oscillating sprinkler. Oddly enough, the very same hose/sprinkler combination works perfectly fine when attached to the other pressure regulated faucet. I've checked water pressure on both faucets and the pressure is slightly higher (44 psi) on the faucet which does not work, as it should be. Pressure on the other faucet is 40 psi. There are no any leaks in the house. It just doesn't make any sense that a sprinkler connected to the faucet with higher pressure will not work. See the attached image. Any suggestions?

 

[speedbump]

The only thing I can see from your picture is that the pipe feeding the faucet in question is 1/2" while the pipe going through the pressure reducing valve is 3/4". Not sure what size pipe feeds the other faucet, but if it's 3/4", that may be your answer.

One other thing I see is that you have BIG mosquitoes there.

 

[indifferent]

The other pipe is 1/2" too.

 

[speedbump]

But are they both the same length?

 

[indifferent]

No. This pipe with the problem is longer, about 20 feet. The other one is maybe 10 but that really shouldn't matter at all. I can't even use a 30 feet hose with it versus a 100 feet long hose which works fine on the other faucet.

 

[speedbump]

Well, length does matter. Friction loss increases with length. However I don't think 10 feet would make much difference.

Either you have a blockage in the pipe somewhere or your faucet is messed up.

 

[majakdragon]

Trying to figure out why you would have a pressure regulator, at all, if the pressure before the regulator is less than 80 pounds. No need for it. You obviously have a clog somewhere in the line that will not operate a sprinkler. First place I would check is the outside faucet valve.