AWS Water Level

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Full Member, Jester. This user is located in Virginia Beach, Virginia - Zone 7b. This was originally posted on June 18, 2009.

This may be a stupid question, but here I go...

I have the AWS on all 3 of my EBs and everything seems to working properly now.  I have tested all the boxes to see if they are level and I also have tested each individual AWS sensor.  I've been having issues with my cucumber and squash plants, so I wanted to fill the EBs traditionally to see how full they were.  Well to my surprise the EBs took a lot of water to fill...  I would think the AWS would keep the EBs full to the top with water... Am I wrong or is there something wrong with my AWS..??  Thank you again everyone.

Jester

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, CeaseFire. This user is located in North Central Mississippi - Zone 7b. This was originally posted on June 18, 2009.

My AWS doesn't keep boxes "totally" full either. Maybe they are allowing room
in case Doc wants to add his nutrient solution.

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, cushman350. This user is located in Tomato Hell, Wichita Falls, TX Zone 7b. This was originally posted on June 18, 2009.

I've never performed such an experiment but I would think there would be no negligible difference in the moisture content of a 50% full reservoir and a 100% full reservoir. The goal being to always have water available. That being said, couldn't the shutoff point be raised by shortening the level sensing down tube or raising the water tube a bit?

[EarthBoxAdmin]

Disclaimer: This post was originally posted Hero Member, gardendoc. This user is located in Ocean Springs, MS Zone 9a. This was originally posted on June 18, 2009.
I agree with cushman, it is all about the available water. 

I seriously doubt there is a built-in volume for my heretical rantings 

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, psh. This user is located in Texas Coast Zone 9a. This was originally posted on June 18, 2009.

I'm in agreement also. If the AWS filled the earthboxes up completely, it wouldn't take much to make the water start flowing out of the overflow hole. The slightest tilt of the box will make water start dripping out, and you could end up wasting a lot of water.

If you look at the wicking system of African violet pots that have been around forever, the wick keeps pulling up the water even though the water level goes down to almost empty. As long as the wick stays in the water, the capillary action continues to work until the reservoir drys out.

Philip

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, CeaseFire. This user is located in North Central Mississippi - Zone 7b. This was originally posted on June 18, 2009.

The slightest tilt of the box will make water start dripping out, and you could end up wasting a lot of water.

Yep, it's probably to allow for EB that aren't perfectly level.

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, mjb8743. This user is located in Zone 7, South NJ, Garden State. This was originally posted on June 18, 2009.

Way back when the AWS first came out, this question arose. I think it was Steve (from Earthbox) that pointed out that the box will function the same, whether it has a full reservoir or just 1/4" of water...the point being that the wicking will draw no matter the depth, as long as water is available. The AWS valve has a diaphragm that senses air pressure in the reservoir. If the pressure drops, the valve turns on; pressure rises, the valve shuts off (or maybe the other way around...no matter). The key here is to have a sufficient supply of water to meet the wicking demand. A properly functioning AWS valve will do that. That's one reason an absolutely level box is recommended...or at least orient the box so the tub is at the low point in the slope.

Mickie

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, bdobs. This user is located SF Bay Area 8b. This was originally posted on June 18, 2009.

If you want the water level to be higher just go to HD and buy some clear refrigerator drain hose (its the same size) and cut a longer length. I've retrofitted the AWS system to work with other containers and it works wonderfully.

Brian

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Guest, kittyhawk63. This was originally posted on June 18, 2009.

Disclaimer: This post was originally posted by Hero Member, bdobs. This user is located SF Bay Area 8b. This was originally posted on June 18, 2009.

If you want the water level to be higher just go to HD and buy some clear refrigerator drain hose (its the same size) and cut a longer length. I've retrofitted the AWS system to work with other containers and it works wonderfully.

Brian

Hey, bdobs, that's a good thing to know. Glad you experimented and found out that it can work with other containers. How did you come to decide on how long to make the tubing? Did you measure to the bottom, inside the container, and see how high it was to the bottom of where the AWS head sits? I would like to use your idea for some containers I have.

One more question for now. Do all the containers connected to the AWS system have to be at the same level? In other words, do my non-EB containers have to be at the same level as the EB's themselves?
kh63

[EarthBoxAdmin]

Disclaimer: This post was originally posted by Hero Member, bdobs. This user is located SF Bay Area 8b. This was originally posted on June 18, 2009.

KH
The AWS system is basic genius.  You just need to know where you want the water level, and cut the tubing so that the bottom of the air bell sits at that level, or just a tad deeper.
It works on Bernoulli's Principle to flex a diaphragm closed as the water level (pressure) rises around a sensing cup, and when the pressure rises high enough, the pneumatic diaphragm shuts off.

So once the water level hits the bottom of the air bell and, in essence, seals it off....the diaphram closes and so does the water flow.  Once the water in the reservoir drops below the bottom of the air bell, the pressure up top is now enough tp open the valve and let water in.  The water will rise and again the pressure below the valve will be greater than above and shut off the flow, and on and on and on.

No, they all don't need to be at the same level. Each box and AWS valve is mutually exclusive of each other.  I cant really comment on the needed water pressure to activate the system though.

I am running EB's and non Earthboxes on the same line with no troubles

Brian

[nitrous]

Disclaimer: This post was originally posted by Hero Member, bdobs. This user is located SF Bay Area 8b. This was originally posted on June 18, 2009.

KH
The AWS system is basic genius.  You just need to know where you want the water level, and cut the tubing so that the bottom of the air bell sits at that level, or just a tad deeper.
It works on Bernoulli's Principle to flex a diaphragm closed as the water level (pressure) rises around a sensing cup, and when the pressure rises high enough, the pneumatic diaphragm shuts off.

So once the water level hits the bottom of the air bell and, in essence, seals it off....the diaphram closes and so does the water flow.  Once the water in the reservoir drops below the bottom of the air bell, the pressure up top is now enough tp open the valve and let water in.  The water will rise and again the pressure below the valve will be greater than above and shut off the flow, and on and on and on.

No, they all don't need to be at the same level. Each box and AWS valve is mutually exclusive of each other.  I cant really comment on the needed water pressure to activate the system though.

I am running EB's and non Earthboxes on the same line with no troubles

Brian

Just to clarify things here a bit.  This system has nothing to do with Bernoulli's Principle (which relates to pressure differentials between between gasses moving at different speeds. .  The water control is a two chamber, diaphragm controlled flow controller.  The water level sensor side of the system is open ONLY at the bell end of the clear tube.  The bell serves an important role in pneumatic control system.  the volume of the bell is pressurized as it is forced into the clear vinyl tube.  it is this air pressure which takes the normally OPEN valve and closes it by pushing the diaphragm against a very tiny orifice. If the orifice wasn't there, the pressure side of the two chamber system would require much more pressure to seal the water inlet. 

so, while level of the box is important, it isn't critical.  For example, if the long axis is tilted such that the sensor is lower than it should be, you will get incomplete filling.... remember, the sensor simply detects and acts on water depth.  On the other hand, if the box is tilted back (away from the overflow hole) on the short axis, the system will continuously sense a low water condition and as a result, never shut off. 

This isn't complicated.  The most common problems that these systems suffer from is 1) debris from an unfiltered water supply that eventually prevents the diaphragm closing the orifice.  Remember, the smaller the orifice, the more easily it is blocked.

The patent is well worth reading.  https://patents.google.com/patent/US6848483B1/en