I am having a well drilled, around 150' deep and I spoke to a well man and he said I don't need a pressure tank that the sprinkler system will call for water and the well will pump water to the sprinklers. Could someone give me an idea as to how to plumb for this idea to work? I assume that the water outlet from the well is attached directly to the sprinkler zone box and if one would connect power to the pump it'd pump continuously unless...there is some type of valve or switch that would call for the well to pump. Please advise.

 

Yes, the pump for the irrigation system needs a pressure tank.

The pump relies on system pressure to start and stop. The system pressure in turn is mostly governed by the size of the air cushion in the pressure tank. As the air cushion expands as water is used, the pressure goes down. Pressure controlled switches turn the pump on and off.

The pump will wear out quickly if it has to start and stop frequently in very short time intervals which is what would happen if there is no pressure tank or if the air cushion got too small from leakage or (for non-bladder tanks) absorption.

The pressure tank is typically placed between the pump and the first usage point (here, the sprinkler zone box or manifold). The tank does not need both a water inlet and a water outlet; just one pipe off a tee in the water line will do. (There must be an air valve on top to allow adjustment of the size of the air cushion).

 

Thanks for your quick reply! You confirmed my suspicions about this particular business.
Thanks again

 

Wait a minute. If your sprinkler controller has a pump start realy, which most do, it will turn on the pump at the same time as it turns on a sprinkler zone. In this way you do not need a pressure tank or pressure switch.

But if you want to run a garden hose or anything that is not connected to the sprinkler controller, then you will need a pressure tank and pressure switch.

 

They are marking the utilities in the yard as I write and when they come to drill the well I'll have them try and hook up the water line as you suggest.
Thanks!

 

If the pump can be on continuously and work against the sprinkler heads and let the latter govern the rate of flow. then you might get away with no pressure tank. But if the pump output is not perfectly smooth (there is some pulsation) the pump will suffer a lot more strain in a stick slip stick slip form of mechanical action.

The way the piping and other parts are hooked up need not be changed to accommodate a pressure tank.

 

I don't know a lot about this subject but the pump is a continuous run pump. I hate to put a pressure tank in the garage as I'd have to cut out a piece of the garage slab to accommodate a big enough drill and drill three holes to the outside of the house (2 for water in/out and pump wires.
Then, I have a sidewalk opposite where the tank will be and I'll have to cut a piece out of it to get to the holes and go under the walk with lines to the aforementioned holes just drilled. It'll be a lot of work and I'm not as young as I used to be (obviously this applies to everyone). I'm going to ask the well driller guys when they arrive about drilling the holes-provided they bring a big drill and cement bit. It'd be worth it to pay someone to do the work-unless you folks have an easier idea, I'm, certainly open to suggestions.

 

Valveguy has it right. Unless you want to use the water for washing the car when the irrigation system is not on, you don't need a tank.

Where I am sitting, there are hundreds of irrigation wells around me. Some of them use lake water and some use well water and not a single one of them have a tank. Asking around tells me that the typical life of a pump (a good pump, not one of those junky ones from a big box store) is 10-15 years. I doubt a tank would extend that much. I certainly would not do what you are thinking about to put one in.

 

When using a pump start relay in a sprinkler controller, the size of the zones need to match the output of the pump. If the zone lets out too much water, the pressure will be low. If the zone doesn’t let out enough water, the pressure will be high. But when set up properly a pressure tank is not needed.

You can even install a Constant Pressure Valve when using a pump star relay, and it will hold the pressure constant even with different size zones. So you can run zones as small as you want, you just can’t size a zone larger than the pumps output.

There are a few disadvantages to a pump start relay verses a pressure tank and pressure switch. You can’t run water for the house, use a garden hose, or anything that is not controlled by the sprinkler timer. Larger systems will have water hammer when started with a pump start relay. The worst problem is when the Gophers eat the wires going to the sprinkler valve, so the valve doesn’t open when the pump starts. In this situation a pressure relief valve somewhere in the system can help keep from burning up the pump.

Many irrigation systems run off a pump start relay without having a pressure tank.

 

That is something I am going to have to consider-pump life. I had a pump built in 1966 that I just gave away and it was still pumping. That's hard to believe but they do last an extraordinarily long time if not abused. Thank you guys for your help and information. The fact that open can obtain clear drinking water out of the ground to me is a miracle in itself.

 

"the size of the zones need to match the output of the pump."

People around here use ball or gate valves to fine tune each zone.

 

"I had a pump built in 1966"

You are not likely to see that life again. Things aren't made the way they were.

 

Thanks! That is something I can do myself at each zone control-I only have two.

 

If you use valves to control the zones, don't get dumb and completely close both, then turn on the pump. I did that once and had to replace the pump seal.

 

Thanks, I do dumb things on occasion. It seems like I could put a T in the line and have the garden faucet without activating the sprinklers-IF I turn on the faucet first to prevent the pump seal blowout. The line has to be open somewhere anytime the pump is running.

 

I take it back that nobody has a pressure tank around here. I saw one yesterday. It was a tiny little 1 gallon tank and I think it was on there because the pump was a POS from harbor something. It was plumbed in on top of the pump.

 

One last question, if the zone box turns on the pump, how does this occur? Are there other valves I'd need? Would I need a check valve? and why would I need a check valve. I understand why one would need a gate or ball valve because the pump might have such force that the water might end up in the street vs the lawn.

 

You will have a solenoid valve for each zone. You will have an add-on relay (you have to buy it separately) to turn on the pump. At programmed time the controller will tell the relay to click on and open one of the solenoid valves. Then after the designated time, the solenoid closes while the other one opens. Then the relay clicks again and the solenoid valve closes. You never close the manual valves because they are just for tuning. Oh, and when you are doing that, let a little out in the street because there will be minor differences between runs. If you don't let a little in the street you will constantly be fiddling, have dry spots, etc.

I very good site that explains how to lay out a system is rainbird here:
Rain Bird Irrigation Learning Center

 

Thank you for that interesting post. I guess an irrigation company will have access to the solenoids and do the job. I appreciate the details you gave, thanks!

 

Another final question: What are the solenoids called that I would need? I've searched the internet and can't find anything but standard irrigation solenoids.

 

Standard sprinkler solenoid valves is all you need. If a pro does the irrigation work, you may not need any other valves (I prefer gate valves) since, in theory he will balance things right. I like to swap heads in and out and change things frequently since I have a garden, so I use the extra valves. Here is how I set mine up: Water source from pump goes to solenoid valve which goes to gate valve which goes to sprinkler heads.

Solenoid valves are either full open or full closed. Gate valves let me fine tune.

 

Thanks Vey, I appreciate your explanation.

 

Closing old thread... Please start new...

thanks