Hello, I have an irrigation pump that draws water directly from a concrete canal. There is no pressure tank in the system, only a foot valve on the end of the pipe in the canal to hold the prime. So when the pump is off, there is no pressure in the system. We prime the pump at the beginning of the watering season and don’t have to prime it again as long as the pump doesn’t run dry. The canal does not always have water in it, and when there is water in it, the level can drop without notice. As a result, there’s a danger of running the pump dry when the water level drops. The whole irrigation operation is very much a “look and see†process. Look to see if there is water in the canal. If so, turn the pump on. When the pump is running, keep an eye on the sprinklers to ensure water is still being delivered. If no water, quickly run outside and shut the pump off. This “look and see†process is problematic as it makes a “watchdog†out of you and it’s difficult to start any other projects or go to town with the pump running. Plus, we have a sizeable investment in the pump and don’t want to replace it because it ran dry. What I would like is a way to protect the pump by shutting it off automatically when system pressure drops, while still being able to perform the initial start without system pressure. I have a couple of thoughts on how to do this, but if there are other solutions, I’m interested in hearing them.
The first idea is a pressure switch(s) that would allow a pre-determined amount of time to pass for the pump to start and build pressure. Once the pump is running the system builds pressure. But once pressure drops or never builds after a predetermined amount of time, the pump shuts off and will not retry until it’s reset. I haven’t found a pressure switch that has a built in delay mechanism and I don’t have the know how to configure the right combination of delay switches and pressure switches to make such a thing work.
The second idea is to have a manual override via a momentary switch. When it’s time to start the pump, you push and hold in the momentary switch, turn the pump switch on, and when the pump has developed pressure and water is flowing from the sprinklers, release the override switch. When the pressure drops, the pump shuts off. Again, I don’t have the know how of wiring a momentary switch into the existing circuits, and with the pump on/off switch 200’ away and the Amps I am dealing with, it may not be feasible.
I have included a JPG picture/file with the current wiring diagram of the pump circuit. I’m thinking this can’t be an uncommon problem, but I have searched and have not found what I am looking for. I have not spoken to an irrigation specialists because the closest one is several hours away. Any help and/or suggestions will be greatly appreciated.
Thank You,
Scott
The first idea is a pressure switch(s) that would allow a pre-determined amount of time to pass for the pump to start and build pressure. Once the pump is running the system builds pressure. But once pressure drops or never builds after a predetermined amount of time, the pump shuts off and will not retry until it’s reset. I haven’t found a pressure switch that has a built in delay mechanism and I don’t have the know how to configure the right combination of delay switches and pressure switches to make such a thing work.
The second idea is to have a manual override via a momentary switch. When it’s time to start the pump, you push and hold in the momentary switch, turn the pump switch on, and when the pump has developed pressure and water is flowing from the sprinklers, release the override switch. When the pressure drops, the pump shuts off. Again, I don’t have the know how of wiring a momentary switch into the existing circuits, and with the pump on/off switch 200’ away and the Amps I am dealing with, it may not be feasible.
I have included a JPG picture/file with the current wiring diagram of the pump circuit. I’m thinking this can’t be an uncommon problem, but I have searched and have not found what I am looking for. I have not spoken to an irrigation specialists because the closest one is several hours away. Any help and/or suggestions will be greatly appreciated.
Thank You,
Scott
