sizing new pressure tank and CSV for use with Clack air injector prior to softner

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LLigetfa

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How does the injector see more pressure when it is between the pump and the pressure tank when the pump is controlled by the pressure switch on the tank tee?

The injector goes between the pump and the pressure switch. It is a major enough constriction to make the pump pressure go higher than what the pressure switch sees.
 

gojoe3

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Why do you think you need so much drawdown? You probably need more contact time in a tank that can be flushed out. Yes, it is easy to get more contact time and more drawdown by having a larger tank provided you have the room for it.

Again, as I mentioned before, tune your system by matching draw to supply to not cycle as much.

The composite hydro-pneumatic tank I mentioned is serviceable whereas most bladder tanks are a throw-away. You really should not use a bladder tank anyway as the air you inject has no properly designed place to be vented off. You shouldn't let the air collect in the top of your media tank.

I assumed I needed more drawdown because of how my pump cycles when I am watering the lawn in the summer with an impulse sprinkler.
It seems to work fine at all other times. That is why I have always been interested in the prospect of using a CSV.

Earlier this week when I had a well guy, fairly familiar with my system, come over to determine what was wrong with my pressure tank. I also mentioned the lawn watering issue. He stated that the best thing to do was to replace my existing (12 gallon drawdown at 40/60) P tank with a larger capacity tank like the 251 or 255 (with drawdowns of 18.2 and 23.8 at 40/60) and that he would install a 50/70 pressure switch instead of the 40/60 I now have. He did not know anything about a CSV. Nor did he address the issue of the air injector even though I pointed that out to him. He just stated that a larger P tank would benefit my well pump by cycling less often and that my conditioning equipment would also benefit from the higher PSI I'd get from a 50/70 P switch.

I realize that my system would probably benefit from a properly sized retention tank and that it would be much easier to maintain if it could be flushed out by having a drain at the bottom. I'm all for this. Its just that my old system (which I installed in 2003) had incorporated a UT-80 with a compressor, a 8" x 48" "off-air tank" (that's what the guy who sold it to me called it) and a pH neutralizer. So, when I changed my system over to using an air injector as the oxidizer, the installer who sold me on adding a softener to aid in filtering the iron, determined that the 8x48 with an AVC would suffice and remain in-line after the P tank as a retention/contact tank, and that the UT-80 would not be necessary?, or would have to go because of space requirements for the new softener and brine tank? (I don't recall why the UT-80 was not re-used as the contact tank)

I will definitely take your advice and "tune your system by matching draw to supply to not cycle as much", once I determine which replacement components to specify.
So, I guess if I want to water a certain portion of my lawn efficiently and effectively, as a prerequisite for my determining my system componentry, then I should choose a certain sprinkler head and manufacturer which states the required GPM usage, so that I can make an informed decision.

Thanks for pointing out that the hydro-pneumatic tank is serviceable. I'm just not sure I want to deal with the additional maintenance which may be required because of the numerous parts associated with using that type of tank in my system.

As per your statement : "You really should not use a bladder tank anyway as the air you inject has no properly designed place to be vented off. You shouldn't let the air collect in the top of your media tank."
I neglected to tell you that there is an ACV? (pressure relief valve?) on the top of my existing "off air" tank. I just don't know if it works. I will be taking that tank apart to see what is in it, when I shut down the system to replace the P tank. Hopefully it has at least worked to vent/release accumulated air, even if it hasn't worked as a proper contact tank.

I really appreciate all your knowledge and input.
I just wish I was smarter so that I could comprehend it all quickly and put it all to the best use in a short period of time.
It takes me forever to "get it".
 

gojoe3

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Another reason not to use a bladder tank is contact time. If/when water is being drawn while it is being pumped, it bypasses the tank since the point of entry is also the point of exit. The water needs to go in one port and exit another so that it has hang time inside the tank.

Gottcha, thanks for the explanation. But why can't my existing 8" x 48" tank be considered the contact tank?
Can I reconfigure the tank I have to make it work better? Ugh! I forgot about the ability to drain it down to clean out the sediment!
 

gojoe3

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You forgot option #6 - tie into city water and use the well only for irrigation.

Thanks for the suggestion, but...

It's not an option. I can't afford it now 15K to 20K. And it would ruin my beautifully landscaped yard, no easy access to the main.
 

LLigetfa

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...why can't my existing 8" x 48" tank be considered the contact tank?

It is and can be, but since it holds less than 10 gallons it doesn't have a whole lot of contact time. It all depends on how much iron you have, how much air is getting injected and through what range of pressure, and how fast you use the water.

Iron removal is a messy business and there is no such thing as no maintenance or even low maintenance. It will gum up the inside of the piping, tanks, and softener.
 

gojoe3

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I don't know how many air injection systems you've worked on other than yours but I have worked on a few over the years. I don't like them but..

How does the injector see more pressure when it is between the pump and the pressure tank when the pump is controlled by the pressure switch on the tank tee? And an injector works with gpm based on the pressure range the pump is operated at.

The mixing/retention tank I posted the link to is a 12" dia tank only 65" tall and is equivalent to a 120 gallon retention tank. And the contact time is greatly reduced to damn near none, Plus it has 3/4" bottom drain.

I suggest maybe using the softener to remove the iron instead of air injection.

"I don't know how many air injection systems you've worked on other than yours but I have worked on a few over the years. I don't like them but.."

Neither do I !

"The mixing/retention tank I posted the link to is a 12" dia tank only 65" tall and is equivalent to a 120 gallon retention tank. And the contact time is greatly reduced to damn near none, Plus it has 3/4" bottom drain."

I really want that tank. Think they'll trade me for mine if I throw in some other spare conditioning components I have lying around?

"I suggest maybe using the softener to remove the iron instead of air injection"

I don't mean to be cynical here but,

I thought both my pH neut tank and my softener were also acting as my filtration media and iron removal tools, already.
I am assuming that the air injection is only oxidizing the ferrous iron so that the ferric iron can be removed by my pH and softener media when either are backwashed.
I am certain that the air injection is not actually removing any iron. Ahem, except for the amounts of precipitated iron sediment that my bladder style pressure tank have captured and held captive, resulting in my current predicament.

Thanks again for everyone's input.

I'm still not certain on which way to go but I have to determine the simplest, most effective, least costly solution, even if that requires replacing the P tank in the near future. At least I can be up and running and then I could test out the effectiveness of the air injector before and after the P tank, and I could see if I can configure the system to use a CSV and run some trials.
 

gojoe3

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It is and can be, but since it holds less than 10 gallons it doesn't have a whole lot of contact time. It all depends on how much iron you have, how much air is getting injected and through what range of pressure, and how fast you use the water.

Iron removal is a messy business and there is no such thing as no maintenance or even low maintenance. It will gum up the inside of the piping, tanks, and softener.

Thanks for bearing with me...I'll be back...having skipped b'fast and lunch to do this...it's now time to eat and digest both the food and all this info!!
 

gojoe3

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It is and can be, but since it holds less than 10 gallons it doesn't have a whole lot of contact time. It all depends on how much iron you have, how much air is getting injected and through what range of pressure, and how fast you use the water.

Iron removal is a messy business and there is no such thing as no maintenance or even low maintenance. It will gum up the inside of the piping, tanks, and softener.

Good to know. I have another tank just like it, not being used. Could I just install it in series and would this help?

What if I added a control valve to the additional tank it so it could backwash out the sediment?

I copied and pasted this idea below from the other thread I have going here :

quoted from a post by craigpump

"I'm not a treatment guy by any means, but he has to deal with iron issue before he puts in a new tank or eventually the same issue will occur. I have seen guys install a short 42 gallon galvanized tank before the Amtrol with a micronizer before the galvanized tank. They plumb the inlet into the middle port and take water out the top of the tank over to the tank T on the Amtrol. Their theory is that the iron will drop out in the galvanized tank which can then be drained off. I personally have never done it."

What do you think? Do you think it should work?
 

LLigetfa

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quoted from a post by craigpump

"I'm not a treatment guy by any means, but he has to deal with iron issue before he puts in a new tank or eventually the same issue will occur. I have seen guys install a short 42 gallon galvanized tank before the Amtrol with a micronizer before the galvanized tank. They plumb the inlet into the middle port and take water out the top of the tank over to the tank T on the Amtrol. Their theory is that the iron will drop out in the galvanized tank which can then be drained off. I personally have never done it."

What do you think? Do you think it should work?
What Craig described there is a contact tank. Since he uses the top port for the exit, the tank will not hold air so it is just like a waterlogged tank. You would still need a bladder tank after it as he said.

You could use a galvanized tank like he said but instead of using the top port, use the highest side port to exit. That way it still holds air so it offers drawdown capacity. The air then gives you some push for when you flush it. At the bottom of every pump cycle a little air will burp out.
 

LLigetfa

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I have a question. Where do you tap in for the outside hose bib that you use for watering? Is it raw water, iron filtered, or softened?

I have four different hose bib outlets; raw for sprinklers away from the house, iron filtered hard water for soaker hoses, and filtered soft water (hot and cold) for washing.

My equipment is down in my crawlspace which is height limited so cannot fit a taller tank. Both my iron filter and softener poke up through the floor under the stairs where the access hatch is to the crawlspace. No room there for a taller tank either. If I want to add more retention and/or more drawdown capacity, I need to daisy chain tanks to do it.
 

Gary Slusser

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The injector goes between the pump and the pressure switch. It is a major enough constriction to make the pump pressure go higher than what the pressure switch sees.
I say the injector should go after the pressure tank and be the correct model based on the pressure switch range the system is operated at.

Installing it before the pressure tank and pressure switch causes rust build up in the water line immediately after the injector and into the switch and its nipple. That in many cases causes problems due to blockage which stops the switch from seeing pressure changes in real time causing a lag in pump operation of both starting and stopping as it should. The cure is to clean the rust out of the line and the switch nipple and the switch which is a real PIA. The frequency depends on the amount of soluble iron in the water.

And since the injector only works based on the pressure switch range, your additional pressure should not be increasing the volume of air as you assumed.
 

Gary Slusser

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Thanks Gary,

It would be great if I could put the air injector after the pressure tank.
You can, iMO that is the only place it should go. See my reply above.

Another option is to go with the advice of someone that has serviced more than just his own air injection system. That would be me or LLigetfa.
 

LLigetfa

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I fully agree that putting the injector before the switch does cause rust to eventually plug up the nipple and get under the diaphragm. I was even starting to respect your advice until you let loose the following BS.

And since the injector only works based on the pressure switch range, your additional pressure should not be increasing the volume of air as you assumed.
The injector works by having enough of a pressure differential across it to create suction through the vortex in the venturi. It must have been lost on you that one of the original complaints the OP has is of not enough pressure, hence the desire to put in a CSV. Putting the injector after the tank will cause enough of a flow restriction to have the opposite effect of what the CSV would have provided, namely a pressure drop commensurate with flow.

The other complaint the OP has is cycle time. The injector presently acts like a dole valve to slow the refilling of the tank, essentially extending that portion of the cycle. Moving the injector to the other side of the tank, will slow the draw and speed up the refill.
 

LLigetfa

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You can, iMO that is the only place it should go. See my reply above.

Another option is to go with the advice of someone that has serviced more than just his own air injection system. That would be me or LLigetfa.
LOL Ja, take advice from some fly-by-night guy that lives in a motorhome parked in a Walmart parking lot leaching free internet.

There is very little value in knowing the pressure before the air injector. What would you do with that info?
Well... there is value, to prove Gary wrong! Put a gauge before and after the injector and see the pressure differential while testing the air draw. Then do the same after the tank. Don't take my word for it and certainly don't take Gary's word! Test it for yourself.
 

gojoe3

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What Craig described there is a contact tank. Since he uses the top port for the exit, the tank will not hold air so it is just like a waterlogged tank. You would still need a bladder tank after it as he said.

You could use a galvanized tank like he said but instead of using the top port, use the highest side port to exit. That way it still holds air so it offers drawdown capacity. The air then gives you some push for when you flush it. At the bottom of every pump cycle a little air will burp out.

I'm considering doing the contact tank setup like Craig described.
I've searched for galvanized tanks online and all I came up with was this one from Sears in stock at a store a couple of hours away from me
http://www.sears.com/shc/s/p_10153_12605_08302951000P

I'm not sure of the quality and I'm skeptical because it states that it is glass lined. Looks like the bottom drain is too far up the side of the tank to use for cleaning out the sediment easily. I can't tell from the photos if it has an opening on the top for the supply.

My other concern with this tank is the stated drawdown, 6 gallons at 40/60 PSI. Could this affect the performance of the bladder tank located downstream?

I'll be calling some local supply houses tomorrow to see if I can locate a galvy tank that will work.

Thanks for the advice
 

gojoe3

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I have a question. Where do you tap in for the outside hose bib that you use for watering? Is it raw water, iron filtered, or softened?

I have four different hose bib outlets; raw for sprinklers away from the house, iron filtered hard water for soaker hoses, and filtered soft water (hot and cold) for washing.

My equipment is down in my crawlspace which is height limited so cannot fit a taller tank. Both my iron filter and softener poke up through the floor under the stairs where the access hatch is to the crawlspace. No room there for a taller tank either. If I want to add more retention and/or more drawdown capacity, I need to daisy chain tanks to do it.

I tapped in before the conditioning components. After the P tank.
It is raw water filtered with a wound filter for each of 3 spigots (hose bib outlets)
I also have a spigot in the garage which is softened and goes thru a shower valve so I have hot and cold for washing off my mountain bike after those muddy winter rides.

Wow, your space restrictions are really limiting. I have much more space but height is and issue.
 

LLigetfa

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Good luck finding a galvanized tank that is made well enough to last. I'm sure there are some out there. I've heard of some folk using cheap electric water heaters as sediment collectors/contact tanks. They just shorten the dip tube a little and replace the cheap plastic draincock with a good full port ballvalve. Not sure how long they last but they come already insulated so as not to sweat.

There has been some reports of problems with Wellmate composite tanks but I think some of them may have to do with excess cycling. My Wellmate tank that I installed in '99 looks as good as the day it went in and had only the AVC replaced recently. I still have the original AVC as a spare which cleaned up well with a soak in Super Iron Out. I would not hesitate to buy another Wellmate.
 

LLigetfa

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I tapped in before the conditioning components. After the P tank...

If iron staining is not a problem with your sprinklers then maybe you could totally rethink the entire setup. I would consider a two-stage setup provided your pump is up to the task.

Run your pump at the highest pressure (60/80?) it (and the conditioning system) is capable of into a bladder tank. The sprinklers see this higher pressure. The drawdown is less at higher pressures but the pump may be running at the edge of its curve so the GPM self-regulates somewhat. Just make sure it cannot deadhead!

Put the injector after the tank Assuming there is enough flow most of the time for aeration. Put a pressure regulator after the conditioning equipment to give you constant (50 PSI?) pressure in the house. The pressure drop across the injector (and across the entire conditioning system) should be evened out by the regulator.

This is all based on supposition that all components can handle the pressure and that the pump curve is suitable.
 

LLigetfa

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This is all based on supposition that all components can handle the pressure and that the pump curve is suitable.

I doubt that the injector would work at those pressures. You would probably have to drop about 20 PSI to get it to work. So, 40/60 at the pump and 35/40 PSI at the regulator.

Just curious what about the air compressor was bad enough to abandon? I've been thinking about adding a compressor to mine so I can have better pressure and more complete aeration. My dealer is trying to sell me an Excalibur system, claiming it will give higher flow with less pressure drop. It supposedly has the injector inside the unit but then it cannot have very much contact time even with the two tank model that I don't have room for. Not sure why it would work with higher pressures either so I am somewhat skeptical.
 
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