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I currently have an off grid water pump system that works well. Grundfos 6SQF-2 Helical Rotor pump, and Grundfos SQFlex controller and system monitor. Getting approx 5 gallons/ minute at peak. Right now, I have to manually turn the pump on and turn it off. I need a means to control the pump when I am not at the property to make sure that my tank doesn't go dry or that I don't over flow the tank. The obvious answer is a float switch, but the distance to the tank is too far to trench for the line and if I laid it above ground it would be eaten by rabbits. It was suggested to me that I could put in a timer relay that would give me the option of having the pump come on a fixed amount of time each day. I wonder if someone has done doing similar and could point me in the right direction for a wiring diagram and parts list? The pump is powered directly from the solar panels through the controller and is rated for 5-240 vdc. Any advice would be appreciated.
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Have you tried to contact the pump controller manufacturer and see what options they have to control the pump. Usually there is a place to install a control contact (like a timer or level switch ) in the circuit -
Yes I did. I contacted Norther Arizona Wind and Solar where I bought the system. I was told that they did not sell anything designed to do what I need to do. They suggested that I get a timed relay that would connect to the controller where the float switch would normally connect. The relay could be set to turn the pump on and off for set amounts of time. Explained that was the concept but didn't have any further info to offer. Not smart enough on electric to work through this myself.Comment
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The way I read it you don't have batteries at the pump.
A possible option is to put a good float valve at the tank and a pressure cutout switch at the pump.
when the tank is full the float will shut of the supply line. When the line pressure builds to preset pressure the pump will cut out.
you would need an accumulator in line to stop cycling.
need to make sure the cutout switch can handle the amps and volts required.
I was going to add a link but it may cause issues. I googled after my post and there are kits availableComment
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Thanks Bala, I do own a float switch and there is a connection for it within the controller. The distance from the tank to the controller makes it impractical, since I would have to trench in very rocky soil or have the wire exposed to be eaten by rabbits. Given the small wire size I assume that it is a low voltage connection, I'm looking for a solution that could be used as a replacement and have been advised that a timer relay would be a good solution. Looking for someone who has done this before or who understands it better than I.Comment
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While I have not done that type of installation before I can tell you there are a number of solid state timers out there. You just have to find one that is rated for the voltage and has a contact that can handle the amount of amps going through it. You also may have to install it in a weather proof box if you can get it to fit inside the pump control box.Comment
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pmeyers , that float switch connection is looking for a set of dry contacts. i.e. it does not have pump level voltage switched at the float like some level switches do.
Can you use a battery? If yes, I have a solution for you.Comment
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Not sure I follow oregon_phil. The float that I have is a sealed unit that has a ball in it. When it is vertical the ball is at the bottom of the float, when horizontal in the middle. No water contact. In any case yes I could use a battery with out a problem. Interested in your solution.Comment
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dry contact means it's not looking for a certain voltage across the contacts. My HVAC system looks for 24VAC across their stupid logic contacts. Some float switches can handle pump level power across the contacts within the float. This float switch can only handle signal level low voltage and has three wires coming out of it. Two control wires and a ground wire.
My solution uses a timer that is sold by Northern Arizona Wind and Sun, but the same functional timer can be bought on Amazon cheaper (cheap too?) for under 15 bucks. The amazon review look rather iffy in some cases. If I was doing a DIY project at home, I would probably try the 15 buck timer, but that's just me.
I haven't done this exact set up since I don't have your equipment, but I am a tinkerer and have done multiple projects fun projects like this before.
You can check out the float level connector functionality on your cu200 by turning the system off, put a wire jumper between the two contacts for the level switch. Then turn the system back on. it should not run.
Before you buy the flexcharge DC timer from Northern Arizona Wind and Sun, you could send them the schematic ahead of time and let them tell you it will work just in case it doesn't work and you need to return it.Comment
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I didn't have time to read the service manual last night, but when the "float switch" (or wire jumper) is closed, the yellow LED in the water tank pictograph on the CU200 control panel should be on.
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Thank you for very much information oregon-phil! My comment re: dry contact shows my level of electronics. My assumption is that the little ball opens or closes a connection. So I think that your saying that when the connection is completed the pump doesn't run. When open, it does? In any case I like what you have proposed. Happy to buy the less expensive timer if you don't mind posting the amazon link. Does the battery power the timer, or does it send a current to the controller? Thanks againComment
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Don't know about Northern Arizona reviewing this. The guy pretty much blew me off when I asked about a timer. Forgot to mention that I had bought my pump system from themComment
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You did mention that in one of your posts.
The CU200 level switch function is already active right now. No float switch is connected to the controller so it functions like it doesn't care about a float switch.My assumption is that the little ball opens or closes a connection. So I think that your saying that when the connection is completed the pump doesn't run. When open, it does? In any case I like what you have proposed. Happy to buy the less expensive timer if you don't mind posting the amazon link. Does the battery power the timer, or does it send a current to the controller?
The float switch for the CU200 is configured as a water tank full sensor. It normally open when in the NOT FULL level position and closes a set of contacts when in the upright FULL level position. The CU200 is expecting a dry contact float switch. Google "Wet vs. Dry Contacts: Knowing the Difference". Do not send any power source to the level switch contacts in the CU200.
The battery ONLY powers the timer. Do not send any power of any kind to the CU float switch contacts.
I'll leave it up to you on how you might charge your battery.
I would still recommend that you jumper the float level connector in your CU200 to make sure you understand how it works. Even though you are working with practically no voltage/current in the connector for the float switch, there is high voltage a couple inches away in your controller. Please be careful when working with electricity. Like I said before, you could turn off your system, install the jumper, then turn back on the system. The yellow tank full LED should light up. If you had a DC shutoff, that would be even safer.
I have updated the document to show the lower priced timer option. Good luck!Comment
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It is not a float switch system I suggested It is a float valve with pressure switch at he pump.
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This solution could work as well because the pressure switch referenced is a simple contact switch. I'm not sure how willing the OP is to reconfigure the pump to storage tank water line, run the pressure switch sensor line back to the controller, add a float valve at the storage tank and perform experimentation to set everything up. Only the OP knows for sure.
I think one unknown is how much hysteresis is built into the pressure switch and that's why you mentioned cycling.
I have no vested interest in one solution set or another. I'm just throwing ideas out there like you. It is good to get more than one thought train going on a problem so people don't get tunnel vision on a particular solution.Comment
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