Automatic cistern pump

[scubabyte]

I'm sure this will sound a little strange - it is.

I live in a community that turns on the 'city' water 3 times a week. Once on, we're supposed to pump the water into our cisterns and make it last until the next cycle. The fun part is that the city turns on the water irregularly.

I'm thinking it would be great to install some sort of sensor/switch that would turn on the pump when water is present. I've poked around the forums, found some flow sensors (but don't really have a "flow" until I start the pump), several float switch types, and even considered combining these with a relay. Before I go that far, I thought I'd toss the challenge to the experts.

The pump is 1/2 hp, 5 amp, 120 volt. The line is 1 1/4 inch throughout. And, I'm not worried about turning the solution off.

Any thoughts or gizmos you know about?

 

[Studhauler]

Is the city water in a pipe and pressurized when the turn it on?
Can you take and post a picture of your set-up?

 

[speedbump]

There has to be some sort of flow coming from the City... right? If so, a Flow Switch would work. These turn on at 1 gpm flow.

Is the pump to increase the flow into your cistern because the City's flow won't fill it in time? How do you control it so the cistern doesn't overflow?

We need more info.

 

[Studhauler]

Like Speedbump was saying; why can't the "city" water fill the tank with its own pressure, why do you need to pump it into the tank? I understand why you need to pump it out of the tank.

 

[scubabyte]

Sorry for the lack of detail - the city has enough pressure to send the water down a ground/street level pipe and that's it. All of our cisterns are above ground containers that are plastic or concrete. The water is pumped up and into the container. While mine isn't, most are high enough that there is only gravity feed to the house from there.

Unless the flow switch is immediate, it won't work as the 'pressure' stops at the first rise. In other words, there's no 'flow' - just standing water. In most cases, the first rise is the pump (ie. most people have them sitting on the ground). I actually get the impression that the pumps are also working as a syphon.

As for the turn off, I already have a float switch that cuts the pump off so the cistern doesn't overflow and waste any water.

Thanks much for your replies and thoughts thus far!

 

[speedbump]

I'm still confused.

Let's do it this way. Where the city water pipe ends; is the pump connected to the end of that pipe and pushes the water into the cistern?

How do you get the water from the cistern into the house?

 

[johnjh2o]

Sorry for the lack of detail - the city has enough pressure to send the water down a ground/street level pipe and that's it. All of our cisterns are above ground containers that are plastic or concrete. The water is pumped up and into the container. While mine isn't, most are high enough that there is only gravity feed to the house from there.

Unless the flow switch is immediate, it won't work as the 'pressure' stops at the first rise. In other words, there's no 'flow' - just standing water. In most cases, the first rise is the pump (ie. most people have them sitting on the ground). I actually get the impression that the pumps are also working as a syphon.

As for the turn off, I already have a float switch that cuts the pump off so the cistern doesn't overflow and waste any water.

Thanks much for your replies and thoughts thus far!

Would it be possible to set up a float switch in the City container?

John

 

[speedbump]

Would it be possible to set up a float switch in the City container?

I don't know, I'm still not sure what his system looks like. So I can't make any suggestions. Maybe he can send a picture of it.

 

[Studhauler]

I think that flow switch will work, as soon as it senses a flow of 1 GPM it will turn on his boost pump to fill the cistern. The float switch will turn it off when it is full. Provided the city water will flow enough with the boost pump turned off.

 

[scubabyte]

I didn't think the rest of the system mattered (as it works perfect) but Speedbump asked:

The city turns on the water flow from a tank that is 50 to 60 feet above the street and 1/4 of a mile away...there is no pump. It goes into a 2 inch line that runs down the middle of the street. All homes have a "T" that feeds their 'system'. So, to answer Speedbump's question, yes the city water ends at my pump. I pump what water I can get into a cistern that is 5x5x8 feet. From there, I have another pump and pressure tank that provides water to the bathroom and kitchen.

I don't mind taking a picture but there's nothing to take a picture of. The pump for the city water sits on a concrete floor at ground level and the exhaust pipe runs to the top of the cistern. In the cistern is a float that when raised, turns off the electricity to the pump. That picture would be a concrete cube as the float is inside. Perhaps I simply don't know what you want a picture of so if you let me know, I'll give it my best shot.

Moving on to John's question - the only city container is the large tank 1/4 mile away. From there, it's nothing but pipes. Are you thinking of creating some container to put a float in? ie. a 5 gallon bucket buried in the ground or something? I have to think about that but would guess I'd suck it dry (and turn off the switch) as the pump is much faster than the trickle we get.

On to the flow switch. I like this idea and only hope we get 1 gpm. The one's I've seen (like the fs-3 or fs-4) are small. I'm guessing I would get some T's and put this in parallel with the city line? Seems simple (and I like simple) if you guys think it will work.

Thanks again for all your time.

 

[speedbump]

OK, now it makes a lot of sense to me. For some reason, I couldn't get from the two inch line to the cistern and you didn't mention two pumps so I was confused.

I'm thinking the only way a flow switch would work is if there were somewhere for a pint or more of water to go when the city turns on the water. This would have to be on your end by the pump. The pint of water moving through the float switch, could turn on the pump, which would than keep the flow going and keep the flow switch happy until the float in the cistern turned it off. I might be missing something, but it sounds like it would work.

Maybe a tee in front of the pump with a check valve on it. The check valve will let water flow out, but when the flow switch kicks the pump on, the vacuum will keep the check valve closed for the rest of the cycle.

 

[scubabyte]

OK - I think I get the picture. Since I have a 1.5" line, I'm thinking of a T with a 1.5 to 3 inch adapter and 6 inches of capped 3 inch (s/b about a pint) facing sideways (so it empties) as my flow catch.

What about the flow switch - Can I put it in parallel with my 1.5 inch line? yes, before the new pint catch I imagine it would be best to be on the bottom side to take advantage of gravity.

Regardless, it's worth a shot and I'm off to order a flow switch! Thanks again.

 

[Studhauler]

I think you will still need a way to drain your catch. The catch will need to be empty each time so the flow has somewhere to go. The flow switch will need to be inline, all the water that flows into your lift pump will have to flow though the flow switch.

Cody

 

[speedbump]

He could probably wire in a solonoid valve to empty it, but he would need a time delay of some sort. I'm not sure how you would tell it when to empty, because it could happen when the pump is still running. This could be a tricky project.

 

[Studhauler]

I think the empty valve should be manual. A simple hose bib would work. When the city is all done running the water, some time before they turn it on again, walk out and empty the catch. Now it is all ready to go for the next time.

I can imagine waiting at home 3 days a week until the city decides to turn on the water is a PITA. Good luck with your system and let us know how it works.


Cody

 

[speedbump]

Your probably right Cody, it would be the simplest and easiest. I was having all kinds of wild ideas running around in my head about how to build a circuit that would do this, then I thought about my Ham Radio buddy that builds all kinds of Circuits from scratch, then we have to wire that to a valve of some sort, now we have to get power to it and on and on. Hose Bibb: $5.00 Simple.

 

[Studhauler]

I have another idea that is not the simplest or cheapest to implement, but probably the simplest to operate. Like I said, "not the cheapest" will be an understatement. You could put the cistern under ground. This is how they did it in the midwestern United States back in the 1800's. They would catch the rainwater from the rooftops and have it gravity flow to the tanks underground or in the basement of the farmhouse.

You wouldn't need any pumps or switches to fill the tank. The city water would flow into it until full. Assuming you had a closed cistern, like a plastic tank. The only pumps or switches you would need are to pump the water into your house.

In the midwest they put then in the ground so they wouldn't freeze in the winter. And the water would stay cool in the summer.

Cody