What is the difference? Does a well pump have a lot more pressure? Sprinkler pump doesn't seem to fill the tank or get above 32 psi, Will purchasing a well pump and mounting it over a horizontal 20 gallon tank fill the tank?



Starting thread: Water-spigot-sprinklers.

 

There is a huge variety of pumps and there is no one "well pump" and no one "sprinkler pump". It all depends on the specific pump you have purchased. What are the pressure and volume specs for your sprinkler pump?

 

Also in this and in your other thread about spigot on sprinkler system, you have not identified the source of water. A sprinkler pump might be able to lift a few feet (10?) from a canal or open source but not from a dug well. A surface well pump will be able to pump higher but again with limits. A submerged pump in a drilled well can pump greater heights.

I suspect that the existing pump is not capable of pumping greater than 32 PSI against the pressure or volume in your tank. That could be due in part to the height you are trying to lift. Sprinkler heads are usually at ground level so the lift is minimal.

 

I live on an Island in Florida and it is fresh water well water. how deep is the well I have no idea, it is used for sprinkling period and has always been faithful in the water supply. I suspect what your telling me is correct, the pump just cannot get above the 30-32 psi and put water in the tank. The specs I don't know which is why a I ask the question if I were to find a more powerful pump could I get the tank filled?
Warren

 

You can get more water into a pressure tank by reducing the preset pressure of the tank and also the desired pump restart pressure.. The consequence is that the variation in pressure from pump shutting off to pump starting again will be greater. All systems with pressure tanks will have the pressure vary as water is drawn and the pump restarts. Most water systems with pressure tanks allow the pressure to drop to no less than half of the pump shutoff pressure which apparently for your pump is 32 PSI , with a suggested pump turn on pressure between 16 and 24 PSI. This may or may not be enough to power your sprinklers.

 

The nameplate on the pump may give the information (head, flow, psi, etc) as well as the electrical specs.

 

With many irrigation systems you don't use a pressure tank. The irrigation controller turns on the pump whenever it's irrigating and shuts off when done irrigating. Even if you leave the pump able to run when not irrigating you still don't really need the tank as long as you have a pressure switch to turn the pump off. The only thing the tank does is limit the on/off cycling of the pump.

 

unable to find specs for GPM or lift on pump. Pump is old, motor new with amps used and such

 

The pump is a 1.65 HP motor 115 volt. rpm 3400 or about. No matter how its adjusted it cannot go below 20 psi without shut off, and despite removing air from tank will not go above 36 psi and not shut off.
Would I be better to get a new pump? 1/2 HP that sits on top of the tank?

 

Most irrigation pumps are not designed to generate great pressure since most sprinklers need about 30 psi. If you want more pressure you'll probably have to look at a new pump. When shopping pay attention to the specs. The motor hp doesn't mean much. You wan to look at how many gpm it can provide and at what pressure.

 

The pump capability together with the pressure switch determine the maximum pressure that will be found in your system.

The pressure switch together with the well supplying capability in gallons per minute (and having electric power) determine the minimum pressure that will be found in your system.

If the maximum pressure your pump can deliver is 36 PSI, you need to be aware that the minimum pressure for reasonable coverage of the sprinklers is probably still around 30 PSI. It is possible you need a new or different pressure switch.

There are various formulas and instructions used to determine how much air needs to be added to or bled out of the pressure tank to maximize the time between pump restarts and stay within the minimum and maximum pressures you selected.

Provided that the air pressure is set properly, you do not worry about the number of gallons of water in the pressure tank.

While nothing forbids having a lot of water in the pressure tank, depending on the minimum system pressure needed and the maximum pressure the system can create or sustain, only a small amount of water might come out of the pressure tank before the system pressure drops enough for the pump to need to restart.

 

Ok so now I have a 3/4 HP pump, I tried a 1/2 HP but it would only run 1/2 second every 30 seconds and the store said it was a bad pump, This has the pressure switch attached to the motor. I changed it from 220 to 115 and under the pressure switch hood it has 4 places to hook up, The black wire is hooked to the inside terminal and white wire to other inside terminal, How do I wire this thing?

 

It would be better for the motor to have it run on 240v.

There are two diagrams below.
With 240v..... both wires get switched.
With 120v..... the white wires/neutral are connected together and just the black wire is switched.

 

You mean leave the motor on 220 even though it looks like its a 110 volt system

 

No. The motor needs to be set to what is there.
I thought it was originally 240v and you were converting to 120v.

 

It does the same thing it runs 1/2 second every 15-30 seconds. All primed and wired as directed

 

What is the water pressure when the pump is cycling off and on?

Are you running the pump on 240 or 120 VAC?

 

set up for 115 and isn't on long enough to build pressure How do I check if this is 220 system or 110 system

 

I always thought it was 220 but previously through pictures they seem to think its 110

 

Ok now with it wired with 220 per your picture and the pump set at 220 it is running and went up to 22 then stopped and began the jack hammering the psi in the tank is 28psi. I turned on a spigot and the jack hammering stopped but the pump is running about 20psi. So i think I do have 220 VAC. and how do i stop the jack hammerin?

 

First, you need to know at what pressure your pump turns on (cut in). Turn off the pump and open the faucet so all water pressure is bled out of the system. Then set the air in the pressure tank to be 2-3 PSI less than your pump's cut in (turn on) pressure. This will allow the pressure tank to do it's job and should smooth out the flow and stop the rapid on/off cycling of the pump.

 

So it jack hammers really fast when I turn on the power which is at 48psi. The gauge is on the side of the pump is at zero so I have a gauge near the opening to the tank and go by that. So when I finished running the water it recovered the tank from about 20 to 48psi then began jack hammering until I either cut the power or run the spigot again. The gauge holds at 48psi. then turning the power back on at 48 psi it begins immediately jack hammering and I open the spigot and the gauge drops to 32 before the pump runs normally. the air pressure is at 28psi.

 

So I checked the air with the tank apparently full of water and it has an enormous amount of air So I let air out (its jack Hammering all this time) until it is at 30PSi. then water starts coming out the air valve. I cannot stop the jack hammering long enough to figure a cut in pressure but I think its 32psi

 

If water is coming out the air valve then it sounds like the pressure tank is bad and water logged. For a pressure tank to work there must be a chamber of trapped air. Most modern tanks have a rubber bladder inside the tank to separate air and water. If that bladder gets a hole then the tank can fill with water. For a short term fix you can add air to the tank but it will need to be done regularly.

 

I agree Its a brand new tank too. Thanks for your help today

 

I'm a little confused.... You can't arbitrarily switch from 120v to 240v. You need to know what you are supplying and wire it that way. If you don't have a meter to test..... is there a single or double breaker supplying the pump ?

I'm trying to figure out what jack hammering is. Is it the pressure switch turning on and off real fast ?

 

Double breaker supply at the breaker box, I'm sorry I meant the pump was turning on and off sometimes slow say every two seconds to once or twice a second. The noise resembles a jack hammer

 

so New tank with air psi 20lbs and 220 wiring to what I am viewing above. pumps water well but at 50 psi rather than shut off it turns off and on real faster and wont stop until spigot opened and water running. So how do I get it to shut off and stay off until I open a spigot or the auto sprinklers run?