Water Mixing Station - Automation

[shafiq_hossain]

So, I've finally set up my water mixing station. It is composed of two barrels, one to collect RODI and the other to mix salt. I have a pump set up in between the barrels. Depending on which valves I leave open or closed, I can either:

1. Direct water flow from RODI barrel to Salt Water barrel
2. Direct water flow from Salt Water barrel to Salt Water barrel - basically water coming out the bottom and going back into the same barrel from the top. This is to faciliate mixing of the salt.

I would like to keep the barrels covered which leads me to the next phase of the project. The following is what I would like to trigger based on the positions of a number of float valves. Let start by describing the position of the float valve followed by the action I would like each to perform:

1. One float valve (Float RODI_LOW) in the RODI barrel to check when the water level is low.
2. Three float valves in the Salt Water barrel to check:
a. Water level is low (Float SALT_LOW)
b. Water level is high (Float SALT_HIGH)
c. Water level exposes heater (Float SALT_HEATER)

The following events are what I'm looking for.

1. If RODI_LOW is ON (water level is low), then turn OFF pump
2. If SALT_LOW is ON (water level is low), then turn OFF pump
3. If SALT_HIGH is OFF (water level is high), then turn OFF pump
4. If SALT_HEATER is ON (water level exposed heater), then turn OFF heater
5. If SALT_HEATER is OFF (water level submerges heater), then turn ON heater.

In each case, I would need to be able to turn the pump or heater back on (possibly using a toggle switch).

I would have liked to hook everything up to my Apex, but I have the following limitations:

1. Mixing station is about 70 feet from my main tank, which is where the Apex system is currently installed.
2. I already have 2 break out boxes. Even if I can hook up a third one, would the cord be too long to carry the signal about 70 feet away.
3. Programming might be too complicated. Well, the wiring might be complicated too.

So, is there any way to do this without having to pull the plug to the pump every time I want a different float valve to trigger an event?

Thanks....

Edit: I forgot to mention that I assume I would need to be able to bypass certain floats. For example, how do I keep the pump on in the salt water barrel after transferring the water from the RODI barrel. At that p, oint, the water level in the RODI barrel will be low. So, I would like the float in the RODI barrel to turn off the pump when the water level goes low, but then I would like to be able to turn the pump back on so I can start mixing the salt in the salt water barrel?

Thanks....

 

[rdnelson]

The short answer is yes, you can build a control panel to do what you want. There is always a way. It can be done with Programmable Logic Control (PLC) which I believe is all an Apex is (but since I don't have one I am not sure) or it can be done the old fashion way with relays and some creative circuitry. I could design something up for you but would need to know the sequence of operation a little better. The other down side to using the old fashioned method is it takes up space to house the required relays.

I would bet that there would be a couple hundred dollars in this in relays, enclosures and misc stuff by the time it was all said and done. An Apex may be able to do the job cheaper. But since I have never seen an Apex I can't say for sure that it would work or how hard the programming would be.

Hope that helps. If you think you want to move forward with the old fashioned method and have a little time I would be happy to put together a schematic wiring diagram for you.

Edit: Here are a few thoughts.

1. If RODI_LOW is ON (water level is low), then turn OFF pump <span style="color: Red">This could also open a solenoid that allows your RODI to start making more RO water thereby filling the container.</span>
2. If SALT_LOW is ON (water level is low), then turn OFF pump <span style="color: Red">If you want to go automated all the way, this could be set up to open a valve from the RODI to pump water into the mixing container thereby refilling it. Of course it would then reduce the specific gravity of the water.</span>
3. If SALT_HIGH is OFF (water level is high), then turn OFF pump <span style="color: Red">I assume this is intended as a safety to ensure the container does not overflow. Is that correct? If not, I am not sure the intent of turning the pump off.</span>
4. If SALT_HEATER is ON (water level exposed heater), then turn OFF heater <span style="color: Red">Easy to do.</span>
5. If SALT_HEATER is OFF (water level submerges heater), then turn ON heater. <span style="color: Red">Again, easy to do and would actually be a function of the #4 above.</span>

 

[shafiq_hossain]

1. If RODI_LOW is ON (water level is low), then turn OFF pump <span style="color: red">This could also open a solenoid that allows your RODI to start making more RO water thereby filling the container. </span><span style="color: blue">That's an idea or I could stick with the current float attached to the quarter inch rodi line which turns off the water flow when the water level reaches the float.</span>
2. If SALT_LOW is ON (water level is low), then turn OFF pump <span style="color: red">If you want to go automated all the way, this could be set up to open a valve from the RODI to pump water into the mixing container thereby refilling it. Of course it would then reduce the specific gravity of the water. </span><span style="color: blue">I was looking around for electronic valves but could not find any. I assume they're pretty expensive, right? But this would make sense only when the mixing container reaches the low level.</span>
3. If SALT_HIGH is OFF (water level is high), then turn OFF pump <span style="color: red">I assume this is intended as a safety to ensure the container does not overflow. Is that correct? If not, I am not sure the intent of turning the pump off. </span><span style="color: blue">Yes, that is correct.</span>
4. If SALT_HEATER is ON (water level exposed heater), then turn OFF heater <span style="color: red">Easy to do.</span>
5. If SALT_HEATER is OFF (water level submerges heater), then turn ON heater. <span style="color: red">Again, easy to do and would actually be a function of the #4 above.</span>

 

[rdnelson]

You can get irrigation solenoids at Home Depot for about $10 each.

Edit: When I get a bit of time, I will draw up a wiring schematic and see what it would take. It could then be tweaked to what ever you want to incorporate.

 

[realfish]

rdnelson99;733679 wrote: You can get irrigation solenoids at Home Depot for about $10 each.

Edit: When I get a bit of time, I will draw up a wiring schematic and see what it would take. It could then be tweaked to what ever you want to incorporate.

Good idea, not sure why I never thought of that since I just put in five new zones at the house.

 

[rdnelson]

Got a few minutes yesterday afternoon to start on the wiring schematic. I will try to get it buttoned up today and get it posted here. Then we can tweak it to your liking.

 

[shafiq_hossain]

Thanks a bunch!

 

[rdnelson]

OK. Here it is. It would take 6 float switches, 3 solenoids and 3 relays. The float switches would need to be Normally Open/Normally closed and the relays would need to be Double Pole/Double Throw. As is most always the case, the wiring ladder diagram may need to be tweaked in the building process. It is hard to think of all the scenarios in your head while putting one of these together. Bench test will usually make you aware of something you forgot. LOL
<fieldset class="gc-fieldset">
<legend> Attached files </legend>

 

[shafiq_hossain]

Thanks. I'll ponder over this tonight. On a side note, let me ask you for another suggestion. Although not related, but I believe it will benefit many of us. We all have expensive electrical equipment hooked up (whether running or not). One power surge is all it takes to knock out a huge investment. Having said that, I was thinking of getting a whole house surge protector hooked up directly to the panel. I found two. HOme depot sells a GE version (my panel is GE) for about $47. It is rated around 1500 joules. Another electrical supply store sells one by cutler hammer for aboiut $130 rated at about 2800 joules. What do you think is more practical. Is the 1500 joules even overkill. If so, then I should be safe with that instead of the more expensive one. But if a home can typically go over 1500, then the more expensive one is extra money worth spent. Your thoughts?

 

[rdnelson]

Surge protectors are pretty much the same as anything. The cheaper it is the less effective it is as a rule of thumb. The best approach is a cascading protection plan. In this case, I would put one at the panel and then again at the outlet. While the joule rating is an indicator it isn't the only one. The biggest danger from a stand point of surge protection is from lighting. A lightning strike in the vicinity can put a very high current on the electrical grid but distance and equipment between you and the strike can limit the effects somewhat by the time it reaches your home. On the other hand, a strike on you property can cause massive damage and not much will protect you against that.

Where I live, we have very good power and are normally not affected by storms. In 6 years we have lost power maybe 3 times. For that reason, I have not put any surge protection or UPS on my system. I know I should but...... But, in other areas you may see much more and the investment in protection could be well worth it.

My best recommendation would be the following:
1. Surge protection at the panel. A reputable manufacturer would be best. Any of them by Cutler Hammer, GE, Square D, ITE, and Leviton would be fine. Something in the $100 to $200 range.
2. A good quality surge strip at the wall outlet. Not a $10 one. You need to spend at least $50 or you are wasting your money.
3. A good UPS. You should figure out the total watts of all equipment to be served by it and get one rated at least that amount. Keep in mind that one rated 500 watts (or volt-amps) rated for 15 minutes will only run half as long as one rated 1000 watts for 15 minutes. If you can, go with an "Off Line" UPS. This means that the utility power just charges the battery and the load runs off of the battery at all times. If it isn't an "Off Line" the utility power will run straight through and it will switch to battery if the power goes out. The reason this is important is it gives a bit of isolation from any power surges that make it past the surge protection (continuing the cascading protection principle). In addition, if the power drops slightly, you are running on batteries and the equipment wont see the dip.

Hope that helps.

 

[shafiq_hossain]

Did some preliminary testing over the weekend. Purchased an irrigation valve and 24-volt transformer. I hard wired the valve (solenoid was already attached to the valve) to the transformer. I plugged in the transformer but the valve did not open up. I'm thinking it was a bad valve. I think I should be able to hook up the valve directly to the transformer, right? My understanding is that the valve will open and remain open as long as the transformer is feeding current. As soon as the flow of current is interrupted, the valve will automatically close. Let me know if my understanding is skewed in any manner.

Thanks....

 

[rdnelson]

If the solenoid is rated at 24 volt AC (should be stamped on it somewhere) and the transformer is rated at 24 volt AC you are correct. Applying 24 volts should open the valve. Most transformers that size are dual voltage rated. They can give you 12 or 24 volt output depending on how they are wired. Make sure you have it wired for 24 volt.

 

[shafiq_hossain]

I've been working through a number of scenarios. One delimma I am running into is how to go about overriding the existing state and turning the pump back on. An example:

Float #3 state turns off Pump because barrel is full. Now, lets say I open up one of the valves which directs the saltwater to the tank. How do I turn the pump back on since the state of the float valve will not have changed? I wanted to find out if there was some type of switch I can hook up to the Break Out box when turned on would allow the pump to be powered up. The Break Out box allows the floats to be connected to it. I wanted to find out if there was any way to hook up a switch to relay and then hook up the relay to the Break Out box. Is there a relay which will present a "state (open or close)" just like the float valves do?

 

[rdnelson]

Float 3 is purely a safety to keep from over filling the saltwater container. The pump runs at all times. It either transfers water from the RO/DI container or it circulates the saltwater. If you want to use the same pump to direct salt water to the tank using automation it would mean another solenoid and and a little creative circuitry. I will see what I can come up with.

 

[rdnelson]

This should do what you are looking for.
<fieldset class="gc-fieldset">
<legend> Attached files </legend>

 

[mschum]

I'm pretty sure most irrigation water valves need water pressure to open/close.

 

[rdnelson]

mschum;743643 wrote: I'm pretty sure most irrigation water valves need water pressure to open/close.

Hmm, never considered that. Either way, there should be pressure built up in the system. The only thing that may not have enough pressure would be the one controlling the RO/DI but you could get by with a standard float valve and not use a solenoid for that one.

 

[shafiq_hossain]

Can a relay be hooked up to the break out box? If not, what about a toggle switch? Will that provide a ON/OFF or OPEN/CLOSE state which a float valve or door sensor would provide? Or is there something similar you would recommend?

 

[rdnelson]

I am not familiar with break out boxes. But, the "Selector Switch" in the schematic can be any type of switch you like. Just needs to open or close the circuit to control relay #2. I just assumed you would want it to be something you manual activate so you can be sure the tank does not overflow. If the switch is turned off, the mixing station goes back to either mixing salt water or transferring RO/DI to the mixing container.

 

[shafiq_hossain]

From an electrical standpoint, how does a door alarm sensor or float valve work? I know both are either in an OPEN or CLOSE state. But what facilitates that Is there some current flowing through the sensor which becomes unrestricted or restricted when the magnet is moved away or close to the sennsor? If so, then something would need to continually send power to the sensor, right?