Problem and Optimal Settings for Logix 762 with 268 Valve

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marc5

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Hi all—new member here looking for advice from this great group. I’d like some help with optimal settings for my softener, and to solve a problem I’m having. I have a Logix 762 controller with a 268 valve. It replaced an old 460i controller on a 168. Resin tank is a Park 12” x 48”, could be 15-20 years old. We are on a well.

Just two of us in the house, averaging about 130 gallons/day. Lab test shows our water has 19 grains hardness and a trace of iron. Programming on this unit is straightforward. My settings:

Hardness: 20 grains

Salt: 9 lbs/cu. ft.

Capacity: 59 kg

DO: 14 days

After a regeneration, it indicates we have a capacity of 2850 gallons. Without guests, we don’t reach this volume, so the 14 day override kicks in. However, a couple of times a year we have a house full of relatives and water use is heavy. Last week we ran out of soft water before the 14 day override. The display showed a remaining capacity of 450 gallons. What do you think is going on? Could I not really have the full capacity of that large resin tank? Could the resin be degraded with age and use?

Before I replaced the old controller, which was dying and could only be used with a manual regeneration, I monitored the hardness of our water daily. It started out at zero hardness after a regeneration, and we could usually go about 17 days before our water got hard.

One thing I’ve noticed about our new unit: it doesn’t bring hardness down to zero at a regeneration like the old one did—usually 1 grain, or maybe a half grain. Any thoughts on this?

So to avoid this “crowd problem” in the future, I’ve lowered the capacity in the settings from 59kg to 42 kg. This yields a gallon capacity of about 1900 gallons. I would appreciate your thoughts on my setup. I’m confused about how the unit adjusts the salt dosing when I do this. What happens? How to improve it…..can I lower salt level? Should I replace resin? Also, ditttohead (and others), can you please comment more on extending days override, which you have written about?

Thanks.
 

Bannerman

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A 12" diameter tank typically contains 2cu/ft of resin. That quantity of resin has a total rated capacity of 64K grains but as some resin will fracture over time and be lost to drain, total capacity is most often estimated as 30K grains/cuft.

The salt required to regenerate 30K grains /cuft is 15 lbs or almost 30 lbs for your 59K grain setting. Your 18 lb salt setting is far too low to regenerate 59K grains capacity.

6 lbs/cuft will regenerate 20K grains / cuft
8 lbs/cuft will regenerate 24K grains / cuft
10 lbs/ cuft will regenerate 27K grains / cuft

As a reduced capacity setting will serve to increase salt efficiency, it is advisable to reduce your softeners capacity setting to either 40K or 48k and reset the BF setting to dissolve the corresponding correct quantity of salt (12 lbs or 16 lbs).


How much iron is a "trace"?
While a softener can remove a modest quantity of iron, it is not as efficient as other iron removal methods. The iron's ppm level is typically multiplied by 4 and any manganese quantity is multiplied by 2 and both those numbers are added to the actual hardness amount to obtain a 'compensated hardness' amount.

While the DO setting can often be set as high as 30 days, when iron is involved, weekly or even more frequent regenerations are generally advised depending on the actual iron content. An ongoing occasional treatment of Iron-Out (or similar) is also necessary to clear-off iron deposits from the resin.

Edited to add: As your softener capacity had been exhausted, it is advisable to restore capacity by performing 2 manual regenerations back to back using 15 lbs of salt / cuft for each regen. A strong Iron-Out solution maybe added to the brine tank prior to each manual regen.
 
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Bannerman

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Thanks for the clarification Dittohead,

While 10" X 54" is a common tank size for 1.5 cu/ft and a 12" X 52" is common for 2 cuft , since 'marc5' specifically mentioned a 12" X 48" tank, I then assumed he either had been supplied a shorter tank than usual or the tank dimension was misstated.

As it is more likely that the softener actually contains 1.5 cu/ft of resin, the calculations previously stated should probably be modified for 1.5 cf instead of 2 cf of media.
 
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marc5

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Thanks, Bannerman and Ditttdohead.

Tank is a true 12” x 48”, stated on nameplate and confirmed with tape. So yes, with 1.5 cu. feet of resin, I have much less capacity than I originally thought. But the calculations made by this unit are confusing me. In the initial setup, I programmed the system size as 2.0 cu. ft. I set the amount of regenerant used as 9 lbs of salt per cu. ft. According to the manual (which I have now read several times) “Capacity is the result of the amount of media in the tank and the salt setting. The default capacity will be changed by selecting a different regenerant setting.” Later, under “Estimated Capacity,” it states, “System capacity is displayed in total kilograins or kilograms of hardness removed before regeneration is necessary. Value is derived from the system’s resin input, and salt amount input. Capacity displayed is a suggested value—as recommended by resin manufacturers. To change capacity of 762 controller, press SET to make the default capacity flash. Use the UP and DOWN buttons to increment to the desired capacity.” Does this mean that the displayed capacity is just a guide, and is not used by the program to order regeneration? If so, then the actual capacity calculated to order a regeneration must be changed by resetting the system size, right?

If this is correct, then my changing only the displayed capacity is a waste of time, and does nothing to change the regeneration schedule. Can I change the system size from 2.0 to 1.5 without a total system reset? No mention of this in manual. No big deal, but all the use data from startup date will be lost.

Bannerman: “BF”….? Not sure what you mean here. Brine refill? Why is adjustment necessary? Not sure how to do this.

Thanks for your help. Any more ideas are greatly appreciated.

PS According to lab testing, my well water has 19 grains of hardness, < .05 mg/L of total iron, and < .005 mg/L of manganese.
 

Bannerman

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Setting the capacity as the total softening capacity, is highly salt in-efficient. Since we have now established that your softener contains 1.5 cf of resin (45000 grains), that would require 22.5 lbs of salt (15 lbs/cf) to regenerate the entire 45,000 grains which equals 2000 grains per lb of salt.

The BF (brine fill) setting is a time setting which is multiplied by the BLFC number (typically indicated on a label) to establish the number of gallons of water to flow into the brine tank. Since 1 gallon of water will dissolve 3lbs of salt, it is easy to calculate how much salt will be dissolved for any given quantity of water.

As your softener has already been obtained, the usual method of setting capacity is to calculate your family's weekly requirements so as to program a regeneration to that required over 1 week or longer, and then set the BF setting to the corresponding amount to regenerate that capacity.

Your requirements equal 19 grains hardness + iron (.05 X 4) + manganese (.005 X 2) = 20 grains / gallon.

2 ppl X 60 gallons/ day X 20 GPG = 2400 grains / day X 7 days = 16,800 grains / week.

As your requirements are relatively low, you can program for high salt efficiency such as 6lbs/cf or 9 lbs for your 1.5 cf.unit. That setting would regenerate 30,000 grains (20,000 X 1.5) of usable capacity which would also extent the regeneration requirement to: 30,000 / 2400 = (12.5) 12 days.

As the valve manufacturer does not know the capacity of the softener the valve will be installed on, a capacity setting is preset as the factory 'default' which must be changed to correspond to each specific configuration.

It appears appropriate to program your capacity setting to 30K grains while keeping your 9 lbs salt setting which will provide 3333 grains / lb salt which is highly efficient.

The appropriate capacity setting will result in the softener regenerating at or slightly before that capacity is consumed. The brine setting needs to correspond to the capacity required to be restored to the system.
 

marc5

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I was discussing my apparent reduced capacity with someone knowledgeable about my system. When I told him that my media was probably 15 to 20 years old, he said that it could be the problem. He said that over time, as the resin breaks down, it washes out of the tank. One way to check it is to darken the room and shine a bright light behind the tank. You should be able to see the level of the beads. Sure enough, I tried it and discovered that the resin level in my 12" x 48" tank is about 18" below the top of the tank--amazing! Is this normal?
 
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Reach4

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You should be able to see the level of the beads. Sure enough, I tried it and discovered that the resin level is about 18" below the top of the tank--amazing! No wonder I don't have 2 cu. ft. of capacity in my 12" x 48" tank.

Perhaps this tip can help other folks. I'm going to replace my old beads soon.

A softener tank should not be topped up with resin. I think the norm is "50% freeboard" which means the tank would be 2/3 full.
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Picture from https://terrylove.com/forums/index.php?threads/gravel-bed-question.31555/

However, there is more to it than quantity. If your softening is not so good and your resin is 15 to 20 years old, replacing it seems wise.

In https://terrylove.com/forums/index.php?threads/centaur-carbon-filter-s.49445/ Ditttohead talks about a 12x48 tank and says it can hold 1.7 cuft of media.
 
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