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Pump turn off if filter clogged

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BCRUMB

Active Member

Posts: 12

1

Wednesday, July 20th 2005, 2:52pm

Pump turn off if filter clogged

Help, I want to put a filter before and after my pump from the dirty ground water I will use. I think I need a device that will shut the pump off if the flow is weak(since this may indicate my filters are clogged). Anyone know what type flow switch I need and where I might get one? Part number would be great. What about how to wire it it?

Thanks,

Bcrumb

BCRUMB

Active Member

Posts: 12

2

Wednesday, July 27th 2005, 11:50pm

Just thought I would update and give more info. I have my system up on county water already. Paid a guy who does commercial sprinklers for a living to do my house. He helped me greatly to test the pump and GPM and such, so I don't really mind if I paid a little too much. Paid $2200 for four zones. Had to buy my own pump but he is giving me a 1/2 HP StaBrite pump that we tried to use but needed more umph. Ended up settling on 2 HP which I had to purchase separately($450). For this 2200 dollars I got a total of 15 Hunter I20s, 4 Hunter scrubber valves, and a Rain Bird ESP Modular outdoor controller. He also dug about a 75 foot trench I needed for power to a Gazebo and routed county water to the back yard for me so I could have a spigot near the pool in addition to helping me figure out whether I could actually uset the water under the pool for irrigation. It smells, but there is plenty of it. Supplied 25 GPM for 1 hr before running dry. Each zone only uses about 9 GPM with the currently used 1.5 nozzles that are installed.

After doing more research, Can I use the rain sensor terminals to attach a device that will cut my pump off when current increases or decreases beyond some preset levels. This could be an indication that the well is dry, the pump sucked in a rock, or the output filter is clogged? Or should I consider some sort of flow switch to turn the pump off when there is no flow. The only problem with this method is that there be no flow when the pump is off so it would hold the pump "off" unless there was a delay circuit or pull up resistor of some sort.

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

3

Thursday, July 28th 2005, 4:43am

Using a two horsepower pump to push nine gpm is two times preposterous. The basic idea is to save money in operating costs, and a good 3/4 HP jet pump could deliver 9 gpm at almost any usable suction lift. My Goulds book shows a 3/4 HP jet pump lifting 10 gpm 25 feet on the suction side, and pushing it at 40 psi. If the sprinkler system layout requires higher pressures at the heads, then it is a very bad layout, given the knowledge that it is to be fed with pumped ground water. And if you were stuck with needing higher pressure, 1 HP jet pump could have delivered it. More to the point, the performance of the half-horse pump should have been evaluated, and the sprinkler system designed to fit. Not the other way around. If it takes more zones, with less heads per zone, no big deal. As for a safety shutoff, you use the pressure-control switch that comes installed on most shallow-well pumps, and add a tiny pressure tank on the outlet side of the pump. Pressure above a certain amount (like you'd get with a clogged strainer) will cut off the pump power.

BCRUMB

Active Member

Posts: 12

4

Thursday, July 28th 2005, 7:20pm

U are probably right, WB. At the time, I thought we were going to have more heads per zone. I guess the sprinkler guy decided to err on the side of caution and cut the zones to 4 heads to make sure the pump could handle it and then also we splurged on the pump. I should try the 1/2 hp first shouldn't I? It may well do the job, then I could return the 2 hp pump. It is a monster, draws over 12 amps on 220v, I will have to run another circuit just for it. Hey, thanks for all your input.

Bcrumb

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

5

Thursday, July 28th 2005, 9:09pm

The thing is to use a JET pump, and not an ordinary centrifugal pump. A jet pump has an internal ejector to recirculate the pumped water in a way that gives you higher output pressure, at the cost of lower flow, which is okay, because you could never make use of the higher flow anyway, given that it's at pressure below 30 psi. (A plain two horse centrifugal can pump eighty gpm, a one horse, forty)

BCRUMB

Active Member

Posts: 12

6

Monday, August 8th 2005, 8:10am

Thanks for the advise. I took the 2hp back and got a 1 hp jet pump from HD. I ended up disabling the pressure switch because it kept shutting down on HIGH pressure. Under continuous operation, it pressurizes to 58 psi and pretty much stays there. I can open 2 zones at the same time and still maintain 50 PSI. Thinking about changing the nozzles on the I20s from the 1.5s installed to 3.0s so I can run it for less time.
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