Sprinkler system low water pressure

[Senin]

My automatic outdoor water sprinkler system suddenly has low to no water pressure. It just came on. Some times it works fine, others it has low pressure. Any ideas on what could cause that?

[Tony Hwang]

Hi, Leak?

[Norminn]

You've looked at the system to make sure there are no broken pipes, right? Sprinklers in our neighborhood used to get very low pressure in early am because that was when everyone had their timers set to start. City or well?

[James]

Have you let it run through more than one zone, to determine if you have low pressure in just one zone, or ALL zones ?

Know this might give you a good hint as to the problem........

James

[Senin]

It's crazy, sometimes they all work, sometimes none work, and sometimes only one zone will come on full blast (and the others barely trickle)---- the one that is the farthest away.

I live in the city. Inspected parts of the pipes, some are buried underground and can't see them. Could it be related to the neighbors?

[Mikepier]

You might have a clog in one or all of the sprinkler heads. Remove them, flush out the line, and try it.

[James]

I would think that if there were a clog in a sprinkler head, why would they work part of the time, but will not work at other times ?

How about the water pressure in your house.... does it seem to stay even, always a good pressure ?

Do you use a pump, or do you have municipal water ?

James

[Harry K]

Based on that description, it is a system pressure problem. I would install a pressure gauge and see what the pressure is doing both with the sprinklers on and off and at different times of the day.

I suspect that someone up thread has it correct - all the neighbors trying to water at the same time.

Harry K

[RicodJour]

Sprinkler systems need both sufficient pressure and sufficient flow volume. One or the other might not be up to the task.

It's entirely possible that it is a neighborhood problem (assuming you don't run the sprinkler off of a well) - ask around. It is also possible that you have a leak or diminished capacity water main. If your house is older and the water main is galvanized, the inside may be partially blocked - galvanizing doesn't last forever and it rusts from the inside out. That would lower your flow volume considerably. Test it by filling a 2 1/2 gallon bucket at different times of the day and night. Time how long it takes to fill the bucket.

You need to get a water pressure gauge, ~$10, and hook it up to a hose bib and take repeated reading throughout the day and night. Check the pressure with nothing at all running, then turn on the sprinkler zones one at a time and see what the water pressure is at the hose bib. You should see the pressure drop as you turn on each zone, then the pressure should build back up as the heads pop up. It should stabilize at a pressure of at least 30 PSI - that's a fairly typical minimum pressure for correct operation. If you see one zone has lower pressure, you may have a leak.

I suspect it is a combination of problems.

R

[Senin]

Thanks. Where it stands now, the third, farthest away station works great. The other two closer stations drip. Does this sound like an electrical thing or a plumbing thing?

[Bob F]

If the problem zones have automatic drain valves, it could be that the pressure is not getting high enough to close the valves, so the valves leak large amounts of water, so the pressure can't get high enough to close the valves. A master valve that is not all the way open could cause this problem.

Bob

[Senin]

Thanks.

Another strange development. I turned on a hose/faucet near the sprinkler system. Amazingly, then I tested the sprinkler system and all the 3 sprinkler zones worked perfectly.

[SteveB]

Low water pressure. Leak. Faulty diaphragm in actuator. Obstruction.

Steve

[SteveB]

Gawd, I love my Rain Bird Maxi Paws on a high pressure irrigation water supply. A mouse would go through that system and not get clogged!

Steve

[SteveB]

When the water kicks on, the rocks (obstructions) go to the orifice in the sprayer. Another time, they don't, or rearrange themselves differently. Each time, they drop to the bottom waiting for the next wave. And every time, it's different until they become clogged in one spot.

Steve

[Bob F]

That suggests to me that the valves don't like the high water pressure.

One thing you could do is remove the last sprinkler on the problem zones, then flush the zone to wash out any debris.

Bob