Jet Pump...What the Heck is that?

[Chris Trot]

Who wants to help me save my marriage... I am attempting to use a 1500 gallon water tank to water plants at our nursery. I was planning on attaching a jet pump to the opening at the bottom and then running a 100' hose from the pump to anywhere I needed to water. The problem I have is this: what size pump would I need to move water up 8' (to get over a rock wall) and then 100' but still have a flow rate of about 7-10 gallons. I am hoping to get about 2-3 hours of watering out of the tank, thus alleviating some of the watering burden I place on my wife, thus elevating her mood, which I assume will result in less friction in our marriage...so in a sense if you have any ideas whatsoever about this, you would be basically saving my marriage...or seriously helping me to avoid a highly upset wife who spent 8 hours watering plants...I also understand that I would be unable to shut off the water at the hose end...because it mess up the pump...any help is much appreciated...if I can do this for her...it would be huge...Thanks for your help.

 

[Wet_Boots]

Jet pumps are a good choice, and a 1/2 horsepower jet pump would work for you. If you want the output to work with a hose with a trigger spray on the end, then you want a pressure tank in the configuration, to work with the pressure control that is mounted on the pump.

 

[Sponsor]

 

[Gary Slusser]

I don't know but I'm pretty sure that you can't get 7-10 gpm out of a garden hose 100' long with the normal 1/2 hp jet pump.

Instead of a hose, I'd run a roll of 1" PE pipe and reduce the end fitting to allow connection of a garden hose. And if you wanted, you could add a tee wherever you needed water in the 100'. You could run drip irrigation quite a ways off the line. But you need a pressure tank either way.

 

[Chris Trot]

I was planning on running a 1" plastic tube through the gravel about 10 feet, then up eight feet to a 4x4 post where I will attach a 100' garden hose. I can't run plastic the farther than that because I need a flexible hose to reach among the plants. What exactly does the pressure tank do? I should also mention that the whole setup is running off electric. Do I have to house the whole unit in a little shed or can I simple construct an awning to cover it...hmm...I wonder how well it would go if I told her that the water tank, jet pump, and pressure tank were her birthday present. I appreciate the help.

 

[Gary Slusser]

The tank allows the pump to shut off, then the compressed air in the tank provides the pressure/power to move water until the pump's pressure switch turns the pump on again; pressure rises and switch shuts off the pump.

No to the birthday present idea. I can tell you that this great gesture to help and provide, she won't see it that way.

 

[Valveman]

If your hose or water lines are not large enough to put out 7 to 10 GPM, and your pump is trying to put out 7 to 10 GPM, the pressure tank will fill and drain continuously while your pump cycles on and off continuously. A Cycle Stop Valve will let you use a very small pressure tank, and will keep the pump from cycling on and off, so you can use the water anyway you want without damaging the pump system. But, even a CSV won't fly as a present for the wife!!!

 

[Themp]

I am running a cheapo 1/2 HP pump off of a 300 gallon rain barrel on a 75 foot hose, with about 15 feet 1 inch PVC under the deck. It has very good pressure and I've clean my gutters with it, over 10 feet up.

Here is what you need:

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_7738_7738

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200329784_200329784

http://www.lowes.com/lowes/lkn?action=productDetail&productId=154967-15649-PPS4060&lpage=none

The pressure switch cuts the pump off at 60 psi, when you stop watering with the hose. It cuts back on at 40 psi, when you start watering again. The hose actually acts like a pressure tank in that it has a small amount of flex and gives you a small kick when you start watering before the pump cuts in. You will notice a small drop in spray at the hose end, before it gets up to speed, however. A pressure tank would help, but in my situation I use this for garden watering and such and did not see the need for it. I have a switch by the hose that lets you switch power to the pump. I usually turn off power when not using the hose. Actually folks on this forum helped me with this setup as I was a novice when I started.


Here are some pictures of my setup:

http://thehemps.com/gallery/main.php?g2_itemId=16757

Tom

 

[Valveman]

When not using a pressure tank, be sure to turn power off to the pump when not in use.

 

[Gary Slusser]

Tom, I think you have a centrifugal pump, not a jet pump. And yours is to; "Provide hours of dependable service! Perfect for a number of long-running water transfer applications on the farm, at the construction site and at home.". I don't know how long it will last being cycled on/off so much, especially if you start it with the hose shut off. You should add a small water heater type expansion tank at least.

 

[Themp]

Gary, yes I knew it was not a jet pump. I was going for the cheapest cost. I admit I have no idea how long the pump will last, but I am curious as to how a pump fails being used in this manner. My guesses would be the pressure when it reaches 60 psi and shuts down is hard on the seal back to the motor itself or the capacitor fails because of repeated starts. And adding a small water heater tank to the system would not give me enough water pressure storage to not have the pump cycle in my mind, since the hose is used for 30 to 60 second bursts. Meaning my wife in watering her garden moves from area to area watering and has the hose running no more than a minute or two per area.

We do release the pressure in the system when the power is shut off to the pump by just releasing the hose bib.

Thanks for the feedback, Tom

 

[Speedbump]

That pump won't last long no matter how you treat it, but if you keep turning it on/off in 60 second intervals, you will certainly shorten it's life even more.

Pressure is the least of a pumps problems, they are designed to handle pressure. What they can't stand is cycling and heat. The heat will come when the pump runs dead head with no water running through it.

bob...

 

[hj]

pump

The pump has a finite maximum pressure. If your system will withstand that pressure, then the pump will just "slip" when you are not using any water, but you do not want the static phase to last too long because you need at least a little flow to keep the water from overheating and causing cavitation on the impeller.

 

[Gary Slusser]

Tom, Chris asked about a jet pump. You are making incorrect assumptions. It's the time the pump is off between starts, the shorter off time, then more heat build up in the motor and the sooner the motor fails from overheating. You would have been better off with a jet pump but, add a small tank and you'll extend the pump's life substantially.

BTW, cost is purchase price plus operational expense plus maintenance costs. Cheap is usually the most expensive and means you get to redo things over'n over until you increase the quality of the product; or give up on the project. And costs go way up when you misapply a product by using it in a way it was never intended to be used. Like a centrifugal pump that is designed to run for hours on end moving tons of water (literally) at high gpm rates, not stop and start within seconds spurting at most a couple gallons for only a minute or two.

 

[n8_b]

Tom, I think you have a centrifugal pump, not a jet pump. And yours is to; "Provide hours of dependable service! Perfect for a number of long-running water transfer applications on the farm, at the construction site and at home.". I don't know how long it will last being cycled on/off so much, especially if you start it with the hose shut off. You should add a small water heater type expansion tank at least.

Jet pumps are centrifugals....

 

[Gary Slusser]

I guess you could say that if the jet pump didn't have a jet; but they do and a centrifugal doesn't.

So what difference do you think the jet makes in comparison to a centrifugal without a jet? And tell me why you would call both pumps the same thing although they are different. I guess we could color code'em.