I'm having a problem regulating the pressures on the house and irrigation feeds. We get a banging in the walls whenever a toilet is flushed or a shower is turned on. I know it has to do with the pressure. The pressure in the house tests at 92 psi which I know is way too high. I backed down the valve to 75 and the banging goes away, but then noticed that the sprinkler heads won't pop up. I have to put the pressure at the valve back to 90 before they will come on. The banging pipes don't happen all the time, but when it does, it lasts for a few weeks then goes away. There is a 1" backflow preventer installed after the pressure regulator which is 3/4". Could that be part of the issue? I didn't want to call out the plumber if is is just something simple I'm missing. Thanks for any help!

The irrigation system should not share the house system, but should be on a service branch by itself.

It branches right after the regulator. Should it branch before the regulator?

Why not as long as it has the required backflow device, and if it did not, then it should not be connected to the system ANYWHERE.

Are you checking static pressure or dynamic? Sprinklers should pop up with way less than 75psi. If you're checking static pressure, maybe there's a restriction causing a big pressure drop.

You state that it does fine at 90 psi but not so good thru the regulator which is why I stated that if it was off the regulator, your problem might go away.

I've only been checking static pressure at the house to give those readings. I agree that the sprinklers should pop on less pressure. The other thing I have noticed is that even with the pressure turned up, the sprinklers take a minute to pop up after bubbling. Other systems I have seen take way less time which is making me wonder now about the restriction. There is a large tree near the lines and I wonder about roots. I see some serious digging in my future. Thanks for the suggestion.

If your irrigation/sprinkler lines are self-draining then it might take a little time for the water to fill the line when the sprinklers first come on. That's normal on many installations. If you have too many sprinkler heads on a "zone" that are trying to all operate at the same time then you will have trouble with a lower water pressure setting because the volume of water gets reduced so much. Is your setup trying to operate every sprinkler head at the same time? It is best to divide the sprinkler system into zones that only have a few sprinkler heads so they will work well at normal household water pressure.



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Check for filter screens at the inlets of the regulator and backflow devices.