# Low Pressure Troubleshooting



## GA_Fescue_Man (Jan 7, 2019)

Hope things are going well. I am having some trouble with low pressure on my sprinkler system and just wanted to get some ideas for trying to troubleshoot the problem before I call a company to come out.

The system was already installed when we bought the house in 2012. It is a 4 zone system with 21 sprinkler heads. The system does not have a backflow preventer. In the fall of 2016 I replaced all of the heads with Rainbird 5004 rotors. In the fall of 2017 a company replaced the 4 valves at the valve box with Hunter PGV valves and also installed a manual valve drain (to winterize and drain water from the valves). In the fall of 2018 I regraded part of my front yard and we had to re-install the Zone 2 lines because they were impacted during the grading. After re-grading the system was working great as before and I renovated my yard with TTTF, watering daily until the turf was established. I'm in GA and I winterized the system in November 2018. In February of this year, I applied my Round 1 application, turned the sprinkler water supply on and watered in my application with about 0.5 inches of water. Everything was working wonderful as it always has.

This past weekend, after applying my Round 2 application, I turned on the system and the pressure was definitely lower than normal on all 4 zones. Water is coming out of all the heads, but as an example, instead of spraying a radius distance of 25 feet with a nice vertical fan pattern, it is now spraying 15 feet with more of a linear stream of water coming out. Basically, the pressure is lower on the entire system for some reason. I have scouted the area for leaks and did not see anything, and because the entire system pressure went down, it does not seem like it's a leak in one of the zone lines. I also double checked the main water shutoff knob to make sure it was turned fully on and it is.

One thing that I noticed that I have never noticed before was when the sprinkler system was running this time, the water pressure was lower inside the house (kitchen sink had a smaller volume of water coming out and the shower head in the master bath had less pressure as well). In the past, I usually run the sprinkler system in the early morning hours (2 AM to 8 AM) and have never really noticed the lower pressure inside the home. Is it normal for the water pressure inside the house to be lower when the sprinkler system is running?

Today, I will double check the piping around the valves and the manual drain at the valve box to make sure there are no leaks there. Do you guys have any other ideas on troubleshooting this? I appreciate everyone's time. Thanks.


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## g-man (Jun 15, 2017)

Is this city water? Could you check with the city if they change the pressure?


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## GA_Fescue_Man (Jan 7, 2019)

@g-man I live in an unincorporated part of the county (not in the city limits). I called the county's Water Resource Department about 1 hour ago and spoke with someone there, and supposedly there are no issues with water pressure in my area. I explained the situation about the lower water pressure inside my house when a sprinkler zone was running and she mentioned that "it sounds like a classic pressure reducing valve issue" in the house. She said theoretically you should not have any water pressure loss inside the house, even with the sprinkler system running. She is not a irrigation specialist, just a county water department person, so I'm not sure what to make of that. Can someone confirm that the water pressure stays the same inside the house, even if a sprinkler zone is running outside? If the pressure reducer in the house is not working properly, would that affect the sprinkler system outside? I have not noticed any pressure issues inside the house when the sprinkler system is not running.

I will take some photos tonight to hopefully give everyone a better idea of the system. I will also check the manual valve drain to make sure that is not leaking. My other thoughts are to start checking the flow control, solenoids, etc. on the valves to make the sure the valves are opening all the way. I know some basics about valves, but just enough to be dangerous, so well see. Any other ideas?


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## g-man (Jun 15, 2017)

That info helped me. It is likely that they are sending a high pressure to your house and then there is a pressure reducing device to drop it to ~60psi. I wish the irrigationtutorials website was running.

A pressure reducing device might have a filter. I would check the filter to make sure it is not restricting flow.


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## GA_Fescue_Man (Jan 7, 2019)

Thanks @g-man. Just to clarify. Here is basic outline of my water system.

1. Main water line shut-off at the street.
2. From there, goes for about 5 feet or so and the line splits, one goes to the house and other goes to my sprinkler shut-off and eventually into the valves and sprinkler lines. 
3. From there, the house line goes about 95 feet or so and eventually connects to a pressure reducing device and the main house shut-off. Then eventually goes into the water heater, on to the kitchen sinks, showers, etc., inside the house.

In this situation, would the pressure reducing device inside the house still have an effect on the sprinkler system outside? Also, is there a pressure reducing device at the main water shut-off at the street? Or do the sprinkler valves/heads reduce the pressure coming into the sprinkler lines?

The county water lady said the main water pressure could be up to 200 psi. I'm just trying to make sure that I am thinking about this correctly. I will definitely check the pressure reducing device filter inside the house.


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## g-man (Jun 15, 2017)

If it splits before the reducing device, then no the reducing device should not impact it. But 200psi is way too high for a residential sprinkler system. It is likely the PVC pipe will break at those pressure.

If there is no pressure reducing device at the valves, then the next thing to do it get a pressure gauge and measure your pressures.


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## GA_Fescue_Man (Jan 7, 2019)

Thanks for helping me talk through this @g-man. I think I have found the problem. There is a manual valve drain that is leaking. It is a steady drip every 10 to 15 seconds. That makes sense that the pressure is slightly lower on the entire system. This manual drain starts in the valve box & continues through into the water meter box and drains there. I tried to tighten the drain plug yesterday, but it still has drip. I ran out of daylight, so I will get back out there this weekend. Now I just need to figure out if I can fix it or if I need to replace it with a new one. I have attached some photos and the last photo is a close up of the end of the drain and where the drip is. I'll post back when I correct the problem.

I also need to do some pressure checks on the system. I checked my hose bibb pressure yesterday and it is 42 PSI, but that is the water supply inside the house, after it passes through the in-home pressure reducing device. It looks like there is no back flow prevention device/ check valve or pressure reduction device at the sprinkler valve box. That's probably something I will need to upgrade in the future.

Thanks again g-man. I really appreciate your help with this. Let me know if you have any other thoughts.


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## SCGrassMan (Dec 17, 2017)

I *think* that last pic with the spraypainted plug is where you'd want to put a pressure gauge. It's probably used to hook up an air compressor up to for blowing out the lines at the end of the season.

You'll want to read the pressure with the water flowing TO the valve manifold with all of the valves closed, and then one zone at a time with the water running through the valve.

In other words static and dynamic pressure.

Measuring static at the hose tap won't really give you any useful info unless you are using a hose bib timer.


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## GA_Fescue_Man (Jan 7, 2019)

Thanks @SCGrassMan. Gotcha. I will definitely check the pressure in this spot. The leak is dripping exactly from the spray painted plug area. I tightened up the plug but water was still dripping from just behind that spray painted plug. Is that a compression fitting that connects the plug to the 1" pipe on the other side? It seems like something may have went wrong with that compression fitting (?) just behind the plug, because the water is still dripping from that fitting. That fitting rotates so there must be some type of rubber seals connect things tightly. If it is a compression fitting, can the rubber seals in that piece go bad over time? And also, are compression fittings used as a permanent fix or is there main purpose temporary? Just thinking about how to replace this drain/blow out section if indeed that compression fitting is not working properly.


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## GA_Fescue_Man (Jan 7, 2019)

@SCGrassMan @g-man If I cannot fix that compression fitting (?), one idea I had to replace this section, is to extend the 1" PVC a little bit and attach an automatic drain plug (https://www.sprinklerwarehouse.com/products/fittings/automatic-drains/king-innovation-22163-1-2-mpt-lateral-and-main-line-pipe-drain). Would this be a good idea? Could I still remove this type of drain plug and blow out the system, if needed?


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## SCGrassMan (Dec 17, 2017)

It's more than likely a twist fit. Take it out, clean threads, put like 5 wraps of Teflon and put either it or a new one back in and try your luck.

Yes you can extend but it needs to be bone dry and you'd cut the pipe and glue new on.


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## GA_Fescue_Man (Jan 7, 2019)

@SCGrassMan. Thanks so much. I appreciate you guys sticking with me on this one. Let me see how things go this weekend.


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## SCGrassMan (Dec 17, 2017)

I will say Id err on the side of a slow drip versus tightening it until it snaps! If I were to extend it I'd put a ball valve and air compressor fitting on there so it's 100% air and water tight, yet easy to open up when you need to blow it out.


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## GA_Fescue_Man (Jan 7, 2019)

@SCGrassMan @g-man Just wanted to post an update on my sprinkler situation. My kids were sick for a little bit and then I got sick from them. The germs finally exited the house and I was able to repair the drain valve/blow out section of the system this past weekend.

I took SCGrassMan's advice and replaced that twist fit drain valve with a shutoff and air compressor adapter connection. I will use this adapter to blow out the system if needed (https://www.amazon.com/Winterize-Sprinkler-Systems-Outdoor-Faucets/dp/B0055Q6CRO). That seems to have fixed the low pressure problems for the most part and the spray patterns and distance seem back to normal. The zone 1 pressure still seemed a little low, but that zone has 7 heads on it (this system was inherited and I would have designed it differently ), and after thinking about it, the pressure on that zone always seemed a little less than the others. I measured the static pressure and then the dynamic pressure for the 4 zones. That info is below. Let me know what you guys think about the pressure measurements and if things seem normal? For the most part, the system is operating as it was before. Thanks again.

Static Pressure - 60 PSI
Dynamic Pressure Zone 1 (7 sprinkler heads)- 40 PSI * The end head is the longest distance from the valve box.
Dynamic Pressure Zone 2 (6 sprinkler heads)- 50 PSI
Dynamic Pressure Zone 3 (5 sprinkler heads) - 50 PSI
Dynamic Pressure Zone 4 (1 sprinkler head) - 58 PSI * Water is shutoff at the 2 other heads in this zone. Don't use zone often.


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## SCGrassMan (Dec 17, 2017)

For your low pressure zone, what I would look at:

-sprinkler bodies. Are they 30 or 40 PSI regulated?
-sprinkler heads - are the screens clogged or can they be changed out for something with better distance on less flow like MP rotators?
-are we sure there are no leaks on the supply line to that zone?

I guess you could cap off all 7 and run the zone and see if water flows.


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## GA_Fescue_Man (Jan 7, 2019)

@SCGrassMan These are the sprinkler heads that I purchased from Sprinkler Warehouse (https://www.sprinklerwarehouse.com/products/lawn-irrigation/sprinkler-heads/rotors/rain-bird-5000-pl-r-rotor). Essentially they are the Rainbird 5004 Rotor with PRS (Pressure Regulation), SAM (Check Valve), & Plus (Flow Shut-off). Here is another specifications document from Rainbird (https://www.rainbird.com/sites/default/files/media/documents/2018-02/ts_5000Series.pdf).

1. From what I have read, the PRS function regulates these heads to 45 PSI. You may want to double check me on that. That's interesting. What happens if the pressure on that zone does not have 45 PSI serving the heads? Does it just have less flow? That makes sense. I don't believe there is a way to adjust this function . I think this is just internal to the sprinkler rotor.

2. I'm not sure on this one. For the most part, I have the standard angle 2.0 plastic nozzles inserted at each sprinkler head. I do have 1 low angle 2.0 nozzle that is close to my landscape bed. That head has some tree limbs hanging close by.

3. That's a good point. These heads make it simple just to shutoff the water at each head and check for water leaks along the zone line.

OK man here's my plan.

A. I will double check the dynamic pressure again for all zones, just to make sure of the PSI measurements. 
B. Shutoff the water flow for all sprinkler heads on zone 1 and check for water leaks along the zone line.
C. If needed, I could remove the nozzles from each head and try to flush out the heads to remove any clogs, etc.?

Any other ideas? Is their a flow adjustment on the zone 1 valve that could affect the pressure? How can I check for this on my valve? I have Hunter PGV 1" inline valves. I am just not sure of the exact model #.


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## SCGrassMan (Dec 17, 2017)

I like B and C. Some hunter valves do have flow rate adjustment but you're probably just at the limit of supply.


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## GA_Fescue_Man (Jan 7, 2019)

Thanks @SCGrassMan. Let me troubleshoot that zone soon. It's about the same as it's always been. The coverage is pretty good for that zone, so if nothing is leaking and there are no clogs, I'm just going to deal with it for now. I appreciate your help. Have a good one.


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## SCGrassMan (Dec 17, 2017)

Any time! Hope I helped some.


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## Thick n Dense (May 7, 2019)

Has anyone checked if HD sells the parts used here? I was thinking of trying to save a couple of bucks.

https://www.amazon.com/Winterize-Sprinkler-Systems-Outdoor-Faucets/dp/B0055Q6CRO/?tag=lawnforum-20


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