My well pump cycles on and off... please help!

[arm24jeff]

I have a four-zone irrigation system at my house, using a 60-ft. well and a sta-rite pump. I never had this problem before, but for the last few months, 3 of the 4 zones will cause the pump to cycle on and off during their uses. Basically, the water pressure will get normal out of the sprinklers, then the pump will get up to 50 psi and turn off, and the sprinklers will die down to nearly going in the ground before the pump kicks on again. The back zone, which uses the most heads, is the only zone that this does not happen on. It can't be the number of heads per zone, though, since we had this system for a year where it did not do that at all. I know it is bad for my pump, but I am stumped on how to fix it. Any advice is greatly appreciated!

Jeff
waterlogged, in Florida

[howiek]

Hello Jeff

I'm going to move your post over to the Plumbing Forums (from Lawns) - You'll probably get a better response from the pros over there :)

Howie

[nomind]

Hi Jeff,
- What kind of pressure tank set up do you have, size etc.
Is the pump a jetpump or a sub, what hp. what gpm etc.
Is the irrigation auto control, what type ?
Was it set up by a well or irrigation pro ?
We need detail to even begin to contemplate your problem. :cool:

Do it Right - Do it once

[arm24jeff]

Okay. The pump is a 3/4 hp Sta-rite, it is set to "kick off" at 50 psi, and kicks on at 20 psi. The irrigation is auto-controlled by a Rainbird system. The well was installed by a well-pro, tied into a pro-installed Rainbird irrigation system. The well ran all four zones perfectly for over a year and a half, but the last couple months it cycles on and off through 3 of 4 zones, while the back zone does not cycle. The back zone has the most heads, and those heads run unrestricted. In other words, the other three zones have heads that have been cut back a little bit so they don't spray on the neighbor's houses. What blows my mind though is that there was never a problem until fairly recently. I have to test out the gpm on it, and can do that tomorrow when it's light again. Any ideas until then? Thanks so much! :)

[nomind]

Hi Jeff,
- please post back ALL the info, I really can't do anything without knowing everything I asked. :cool:

Do it Right - Do it once.

[arm24jeff]

Hi Jeff,
- What kind of pressure tank set up do you have, size etc. - 3/4 HP PUMP WITH 4.8 GAL TANK ON TOP
Is the pump a jetpump or a sub, what hp. what gpm etc. JET PUMP WITH 7.5 GPM
Is the irrigation auto control, what type ? AUTO CONTROL (RAINBIRD ESP-6TM)
Was it set up by a well or irrigation pro ? WELL WAS INSTALLED BY WELL-PRO, HE TIED THE WELL INTO THE IRRIGATION SYSTEM, WHICH WAS SET UP SEPARATELY BY A IRRIGATION PRO
it is set to "kick off" at 50 psi, and kicks on at 20 psi.

The well depth is 60 feet. Four zones, the zone that does NOT have issues has 6 heads, while all the other zones have a max of 4 full-size heads, the rest of the heads are simple risers.

What other details would help you? Thanks again for your help and patience. Plumbing obviously is not my thing :)

[nomind]

Hi Jeff,
- I think the key to your problem is in the tank. I'm quite amazed that a pro would set this up with such a small tank. This in itself ensures that the pump will run almost continuously to keep up a pressure. The tank has apparently lost some air, so now the pump will react to that. The temporary solution is to check tank air at the top (while it's empty) then pump in air to 18 psi. The long term and more correct solution is to get a bigger ( at least 33 gal) tank. ( I'm assuming this does NOT serve a house as well ? -If it does, revise that tank size to 60 gal.) :cool:

Do it Right - Do it once.

[Pumpman]

Systems like this are very common in So. Cal.
The system is designed so that the pump will run continuously while the system is in use. The small pressure tank is there to simply give the pump a "cushion" to start and stop against.
Adjusting the pressure switch is usually required so that the pump will run within the parameters that the system requires. Sprinkler heads are rated in GPM at a certain PSI. For example, a head may be rated at 2 gpm at 40 psi. If you have 6 heads on the zone, the pump will be required to deliver 12 gpm at 40 psi. Less heads on a zone will require less water, so the pressure will be a little higher on that zone. This is where you may need to adjust the switch to allow the higher pressure without shutting off.
I'm guessing that the pressure switch is no longer working where it needs to be to accommodate the three smaller zones.
Before you adjust anything though, see if you can install a pressure gauge on the system so you can see at what pressures the system is operating at. I wouldn't want to adjust the pump out of it's operating range.
Just as a note, we've gotten a little more high-tech with this type of system now. We've started using VFD's with 3 phase motors. This allows the pump motor to ramp up or down to meet demand.
Ron

[nomind]

Thanks for explaining that Ron, - kind of a weird system. I'm surprised they can't set the system up so the P/S doesn't have to be constantly adjusted ? :cool:

Do it Right - Do it once.

[Pumpman]

Hi Nomind,
You usually don't have to adjust the pressure switch beyond the initial time. The zones are designed to be similar in size so that once the pressure switch is set, it works through all the zones. Once in a while you have to adjust the differential a little out of the norm to accomodate all the zones, so yea, it's a little weird.
I design the zones with a particular pump in mind and make the system fit the pump. I'll get a little left or right on the curves once in a while, but generally, it works pretty well.
Leave it to So. Cal to be a little weird - haha!!
Ron

[arm24jeff]

Thanks for everyone's input. Sorry it took so long to get back to you, but I've been trying to mull this over. All four zones worked on the pump for the longest time, but only the last 3 months or so has it started cycling in the front three. I think the output of water vs. the intake of the pump is the key, I'm just stumped on how to fix it. Do i need to adjust the pump gauge, or do I just need to increase the output of the sprayers? As far as getting a pressure gauge, where would i find one and what would I be looking for? Thanks again!

[nomind]

Hi Jeff,
- you can get a pressure gauge at any good plumbing supplier or HD. Look for a small 0-100 gauge, usually cost about $5-6. As Ron appears to know more about this system, I'm letting him do the advising. :cool:

Do it Right - Do it once.

[Pumpman]

Hi Jeff,
The reason I wanted to check the pressure on the system was because you stated that the pump turned on at 20 psi and off at 50. I'm assuming that these were the parameters that were set when the system was installed, and I wanted to know whether the pump was still operating there.
Pressure switches will, from time to time, get out of adjustment. A simple adjustment may be all that is required to keep the pump running while the sprinklers are on, and still allow the pump to reach cutout pressure when the system shuts off.
Ron

[arm24jeff]

Hi Ron. The settings on the system haven't been changed since it was installed. If I were to need to change the settings slightly on the guage, how would I go about doing that? Is it the two screws on the back? Please let me know if you need more details. Thanks again for all of your help guys!

[Pumpman]

Jeff,
You don't change the pressure on the gauge, but rather at the pressure switch. The switch is a little (usually gray) box that is sometimes mounted on the motor or piping nearby. The wires from the breaker usually go to it, and then the pump. See if you can locate it and let me know.
Most of them will have Sq. D on the lid.
Ron

[arm24jeff]

Okay, I found the little box that says "D" on top of it, to be the pressure gauge. How do I adjust the switch? Do I need to remove that screw on top to remove that cover? Thanks again for your help... and patience! :)

[Pumpman]

Jeff,
Yes, loosen the nut on top to remove the lid. The nut will not come off.
Right in the middle of the switch, once the lid is off, will be an 3/8" adjustment nut with a spring under it.
Here's what I'd like to try first. Take a nut driver and turn the nut one full turn clockwise. Be careful, as there is electricity real close to the nut.
Then run the irrigation system and see if the pump still shuts off. What we have done by turning the nut is raised the pump cutoff pressure by 3-4 psi. This is usually enough to keep the pump from cycling.
Let us know what happens, ok?
Ron

[arm24jeff]

Hi Ron. I went ahead and turned the nut one turn to the right (the 3/8 " nut under the cover) and it did raise the cutoff psi to 53 psi, but it still cycles off. What psi is too much to let it run up to? It seems like this is the right direction, unless you think there might be something else we can do. The gpm has to be the issue, since the back zone does not cycle off, just the other 3, smaller zones. Thanks again for your continued help with this!!

[Pumpman]

That 3/4 hp jetpump should be able to do at least 60 psi. Have you watched the pressure gauge as the pump cycles to see what pressure the pump shuts off at?
Ron

[arm24jeff]

Yep, it's shutting off now at 53 psi with the adjustment I made yesterday. Should I try bumping it up to 58 or something like that?

[Pumpman]

Just bump it up a little bit at a time, until it stays running. I know this doesn't seem like a correct fix, but the conditions that a pump works in can change. For instance, if for some reason, the water level in the well rose significantly, the pump would react by pumping more water (gpm) because it doesn't have to lift the water as far as when the level was lower.
Keep us posted.
Ron

[arm24jeff]

Ron. Your fix worked!! I went ahead and bumped it up and now the other 3 zones are keeping it stable at 55 psi, so I have the shutoff just above that. They are all now running without cycling. I can't tell you how much I appreciate your help! Thanks again!!!!! :)

[wmccormick]

Your need for a pressure increase has probably resulted from an increase in well output. The water table may have risen in that aquifer, or the inflow (through the screen) rate may have increased due to heavy usage. New wells often get better when used heavily, because they develope more and bigger inflow routes. No screen is 100% efficient, but any screen, especially new ones, can increase in efficiency when used heavily.

W.A. McCormick
Lindale, Texas