Pump Control Relay

I have an irrigation pump (220V) that is currently control by pressure switch, and a pool pump (115V) that is on manual on/off control. I would like to add relay control to these two pumps via my home computer. I would appreciate suggestions/instructions on the types of the relays and the wiring I can use. (I currently control my irrigation valves using a digital output card (5 VDC), and have a few spare digital output points to drive these pumps). Thanks

Depending on the distance of the wire runs and other issues I would not suggest you do this your self.

PS. Because your new and I can’t go back and look at your other posts I’m not going to help on this. But I’m thinking you would need 2 relays on each motor. One to nock up 110 for a long run and one for the 220. The issue would be properly fusing everything so you don’t burn stuff up with a good power flicker or serge.

Hmm. I think I said to much.

garcanser said:

I have an irrigation pump (220V) that is currently control by pressure switch

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Why do you need to computer control the irrigation pump that is controled by the pressure switch... I don't see what that gains you? The other pump can be controlled by a 5 VDC operated relay, many varitieties out there, or they do make pump contactors but not at the 5 volt range probably.

Rancher

Rancher,
why do you need ten water level sensors in a holding tank? Obviously the guy has his mind set on doing this and wants info on how to do it. It probably gains him in some way or he wouldn't be asking for advice on it.

Garcanser, maybe you should get a hold of a computer engineer that specializes in computer activated relays. If people can control the temperature of their home from a computer miles away i'll bet there is a similar program that can do the same for your pumps.

SAM

sammyhydro11 said:

Garcanser, maybe you should get a hold of a computer engineer that specializes in computer activated relays.

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Sonny, you silly boy, he doesn't need a computer engineer to solve this problem he already knows what he's doing. He has a computer digital output card which he is using to control his water valves, he just needs the proper relay to control his pump. Garcanser, how are you now controling your valves, most 5 VDC relays are DIP form factor, most irrigation water valves are 24 Vac.

Rancher

It's not inappropriate to ask a poster what they are trying to accomplish, when they ask some narrowly focussed question. Why home computer control is needed over systems that function just fine on their own, is something that doesn't make a whole lot of sense. Especially when the existing controls consume far less power than a home computer.

You have a couple of choices.

1. Your 5 Volt digital output will probably drive a solid state relay that will operate your pumps directly. You might need two solid-state devices for the 240 Volt pump because you should open both lines. However, if you have a safety switch that can disconnect both lines you can probably use just one for the control.

2. The digital output will probably not drive a mechanical relay large enough for your pumps. Therefore, you would need to drive a small relay with a 5 Volt coil, and let the contact of that relay operate the coil of the power relay or contactor that actuates the pump. You could use a 24 VAC coil for the power relays if you need to string wire across an open space. Otherwise, you can use 120 Volt coils on the power relays. Your final relay for the 240 Volt pump should be a 2-pole relay.

Thank you all for your suggestions.
Currently, all my control valves are driven by 24 VAC relays. If I understand the suggestion correctly, I need to use one of the 24 VAC relays to drive the 240 VAC power relay.
I should probably explain why I want to control the pumps this way. I have a fairly big garden and when I go away on vacation during the summer months, many plants will die if they are not water when the weather is dry. Currently I use a very small computer that is web enabled so that I can turn on the irrigation valve from any where I can have access to internet via any browsers. The problem is I have to leave the pump on. Since my cheap piping system can fail anytime and drain my pond while I am away, the cheapest next step is to allow remote on/off of my pump when I need them. Obviously this is not a long term solution. , but probably reasonably affordable. Make sense?

garcanser said:

Make sense?

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Yes makes sense.

garcanser said:

Currently, all my control valves are driven by 24 VAC relays.

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This doesn't make sense, are you driving the 24 VAC relays with the computer output card?

Rancher

Hey rancher I have one of the cards in my comp that he is talking about.

Its 12 or 6 relays that the computer will turn on or off for you. It the relays on the card work off the 5 volt off the power supply (computer power supply are 12 volt with a split 5/7 volt output). Using theses relays and a 24 volt or I like the 48 volt power supply to run larger relays.

Garcanser all you will need is a 220 and a 110 relay. I think you will want the nomaly closed. You can get both of these at any electrical supply house. Just make sure you tell them you are using a 24 volt system for controls. The one thing you need to look at is the voltage drop on the 24 volt lines.

For the pool pump you can just leave it on and use the relay for the on off.

As far as the irrigation pump the pressure switch is controlling the pump so the irrigation valves are controlling the usage. So you would only let the pump run for a limited amount of time a day. So if something blows you will have less mess?


At the time of my first post I didn’t think you know what you wanted or what you were doing. But I think this is what you were wanting to know.

Hey Nailed, you're right, I got a relay output card also, but he distinctly said 5 vdc output, so I wanted to make sure. I suspect what he has is just relays thru which he is controlling the 24 VAC valves with a 24 VAC transformer.

Rancher

And I understand the part about wanting to turn off the pump controled by the pressure switch, insurance!

If you want to make sure your plants get water while you are away, you should find a trust worthy neighbor. Letting a computer control your water system is the best way to insure the plants will not get water.

Is this the same Valveman that sells his CSV as new technology that we should embrace, and give up the old tried and true ways of well/pump systems.

Valveman, join the 21st century, everything will be done by computer control, even variable flow pumps, better, longer, cheaper.

Rancher

garcanser said:

Thank you all for your suggestions.
Currently, all my control valves are driven by 24 VAC relays. If I understand the suggestion correctly, I need to use one of the 24 VAC relays to drive the 240 VAC power relay.

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I think there may be a bit of confusion about what relays you have, and some standardization of language would be helpful.

A relay is really defined by the coil voltage and the current capacity, so when talking about the Volts of a relay, you should be referring to the coil voltage.

Most relays are rated for 24, 120, and 240 Volts at the contacts, regardless of the coil voltage.

Your computer is producing a logic output of 5 Volts. That 5 Volt signal is apparently driving another relay with a 5 Volt coil. From your comments earlier, you are using 24 Volts through the contacts of that relay to operate the valves.

You should check the Amp and Voltage rating of the relay that you are using to operate the valves. That will determine if you are able to operate a larger relay through those contacts.

It is quite likely that you can use that relay to operate the coil of a larger "Pump" relay. I recently installed a system with a remote control where a very small relay was able to handle 3 Amps at 120 Volts, and that would be plenty.

If you determine that the relay that operates your valves has the Amps/Volts capacity to operate a relay or contactor for the pumps, then you can get inexpensive Double Pole relays to operate the pumps. You only need a Single Pole relay to operate the 120 Volt pump but there is a lot of benefit to having only one model in your inventory.

You should get relays that are "horsepower rated". Enclosed relays that will handle 1/2 HP at 120 Volts or 1 HP at 240 Volts are readily available with 24 VAC or 120 VAC coils. Check stock number 1EZ90 and 1EZ92 at www.grainger.com

If I need something larger I usually use a 2-pole "Definite Purpose Contactor" by Square D, such as Grainger stock no. 5B124, 5B126, 5B127, 5B129, 5B131, or 5B132.

The CSV was designed to replace computerized variable speed pumps. There is nothing better, longer, or cheaper about a VFD. VFD's were 20th century. CSV is 21st century technology. Hi-tech does not have to be electronic in nature, just beneficial, and a CSV is very beneficial. I have been thoroughly trained in electronics, computers, VFD's and the like. That is why I would never use one to control my pump system. I actually like water to come out of the faucet when I need it.

If after reading a few of these suggestions, you still think the computer will water the plants when needed, you are sadly mistaken.

valveman said:

you still think the computer will water the plants when needed, you are sadly mistaken.

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I wonder what Valveman thinks is in those automatic valve timers made by Rainbird and Watermaster... gears and timing motors? Nope Cary, those are computers...

Rancher said:

I wonder what Valveman thinks is in those automatic valve timers made by Rainbird and Watermaster... gears and timing motors? Nope Cary, those are computers...

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Yes they are, and they are no where near as reliable as the old dial type clocks.

The last house I built (2006) that I hope to retire in has a computer that is running 4 cards that have 12 relays on each card.

I live off the grid with PV and hydro 48 volt battery system. I only have 90 amps 220 to run my house (using 6 outback inverters).

As for the computer cards I control temp witch uses 18 relays, outdoor lighting on 10 relays, backup generator on 2 relays (needed 2 times for hydro work), and field irrigation on 10 relays. No it’s not running on a 2MHZ like most would think it’s on a 486. I have a spare setup sitting right next to it so if I fry I just have to switch out the wire harnesses and restart the other system.

Sounds pretty cool, but look out I got beat up for having 10 level sensors in my storage tank so I knew how full it was... A 486 will work just fine for that application.

Rancher

You guys got my interest up. What are these cards and how are they controlled? Is there software that can be programmed to actuate these relays? If so, where can it be found. Freeware I hope!

bob...