View Full Version : Follow up to low pressure thread, lots of new data...

08-29-2007, 06:34 PM
OK, here's a bunch of data to mull over.......I decided to check the pressure of everything after getting a new water meter installed on Tues. Presuure at the closest bib to the supply is 50 psi. If I turn on the kitchen faucet, which is about 10 ft from the source, it drops to 45 psi. When I turn on the sprinkler system, pressure drops to 30 psi at the lowest with zone 4 on, and 32 psi for the other 7 zones. Zone 4 is the one that is causing the most problems and the range for each head is about 18 ft. Oh, and there are 5 heads in this zone. The heads are Rain Bird rotary heads. The system is about 10 years old.

Other zones with the same style heads have ranges from 21' to 24'. Some have 4 heads, one even has 6 and still gets 24' distance. Zone 3 has 4 rotary heads and two spray heads and the range is 21' for two and 18' for the other two. (I assume that the two going 18' need to be cleaned out.)

Checked the neighbors hose bib closest to his meter and it's 48 psi, so I guess I'm getting as much as everyone else in the area.

So.............based on this I'm guessing that I either have a bunch of spray heads that need to be cleaned or that there is possibly a faulty valve? What else do I nee to check? The supply line from the street is copper and has an outside dia of .901' which would indicate 3/4". The line from the meter to the sprinkler system is 1" copper.

Thanks for any help that you can give!

08-29-2007, 06:48 PM
Note that several folks have asked for measurement of the flow on your other thread. Time to get out the bucket and stopwatch.

08-30-2007, 06:14 AM
You might just have a leak. Poor performance plus low pressure at the supply can mean a leak. Poor performance plus higher supply pressure can mean a restriction (faulty valve, tree roots choking a pipe)

08-30-2007, 07:21 PM
OK, here's some more data......filling a 5 gal bucket in the upstairs bath tube took 67 seconds. The same bucket in the kitchen sink, 2 min. 35 sec. A hose bib in the garage roughly 30' from the meter.....35 sec. !!!! Yikes, 35 seconds.:eek: And I made a huge mess trying to hold the bucket up while I was looking at my watch!:mad:

Now the meter readings....With zone #4, which is the worst for coverage, I got 1.25 cu ft per minute. Zone 3, which is about the same for coverage, 1.25 cu ft/m. Zone 6, which has head shooting at least 24'+.....1.2 cu ft/m.

And just for giggles, the bath tub that filled the bucket in 67 sec showed .55 cu ft/m.

So, what have I learned? First is that I should have paid a lot more attention in my fluid dynamics classes 30 years ago and that it seems that I have a lot more pressure/flow at 9:00 PM than I do in the day time when all of the repair guys show up.

So what does all this mean to you guys?

09-03-2007, 11:39 AM
The plot thickens..........went to wash the car this morning and hardly any pressure at all. Checked it and was around 32psi.:( Neighbors was the same so I called the water company, again, and they are suposed to call for an appt. in a day or two. What the heck is going on here????

Seems like there is a drastic difference in pressure from morning to eveing here.