Water Softener settings for Fleck 7000

[Vladimir Zdorikov]

<Paging dittohead or other knowledgeable users>

I've read a lot of the posts on here, but hoping for some customized advice.

I'm trying to install a Fleck 7000 softener at our house. It will be the SXT model with 1" or larger internal flow but I think that does not matter to the core programming parameters.

It will be a 48,000 grain softener i.e. 1.5 cu-ft of 8% cross-linked resin in a 10" x 54" cylindrical tank.

The feed water is 17 grains per gallon. No iron and so no turbulator. City water. Large house, would like high flow/gpm for certain situations.

Will be using metered delayed regeneration mode.

I am planning to use a salt dose of 6 lbs/cu-ft, which means the resin will operate at 1.5 * 20K = 30K grains of capacity. Thus, I will program the control head with C = 30K.

I understand I can use either 0.25gpm or 0.5 gpm BLFC as long as the programming matches.
But what are the tradeoffs between these two -- how to decide and what does it affect?

I'm thinking of a 2.8 gpm DLFC but not quite sure how that is selected. Should it be sized and selected before the injector size, the other way around, or it does not matter? I see some posts saying the DLFC should always be sized larger flow rate than the injector -- is that true, and if so, why?

Same question regarding the injector size -- what factors decide its sizing? I see some information indicating that for my config, I should use a Violet #00 injector which is determined by the 10" resin tank diameter, but I am confused if that should be determined by the salt/brine tank diameter?

Also, I see a common configuration sold by some folks is with the #2 injector, which provides 0.5 gpm brine draw and 1.0 gpm slow rinse according to the charts/datasheet by Fleck. So how exactly do we pick the injector size -- what factors must it consider and in what order?

Thanks in advance!

 

[Reach4]

It will be a 48,000 grain softener i.e. 1.5 cu-ft of 8% cross-linked resin in a 10" x 54" cylindrical tank.

You should get 10% crosslinked for longer life in the face of chlorine.

I understand I can use either 0.25gpm or 0.5 gpm BLFC as long as the programming matches.
But what are the tradeoffs between these two -- how to decide and what does it affect?

Affects granularity of the fill. Let's assume 0.25.

'm thinking of a 2.8 gpm DLFC but not quite sure how that is selected.

2.4 gpm for a 10 inch tank.

Should it be sized and selected before the injector size, the other way around, or it does not matter?

Not related

System info (not programmed)
salt lb/cuft : 6 ; A choice ( efficiency vs capacity)
BLFC : 0.25 ; Brine Refill rate GPM
cubic ft resin : 1.5 ; Same as (nominal grains/32,000)
Raw hardness : 17.0 ; including iron etc
Estimated gal/day : 120.0 ; 60 gal per person typical calc (use for estimate only)
Estimated days each regen : 12.3 ; presuming days each use reserve capacity

Fleck 7000SXT Settings:
DF = Gal ; Units
VT = dF2b ; Downflw/Upflw, Double Backwash
CT = Fd ; Meter Delayed regen trigger
C = 30.0 ; capacity in 1000 grains
H = 20 ; Hardness grains after compensation
RS = cr ; Cr = base reserve on recent experience
CR = 0 ; 0 is default (leave it)
DO = 30 ; Day Override (typ 30 if no iron/Mn)
RT = 2:00 ; Regen time (default 2 AM)
B1 = 8 ; Backwash 1 (minutes)
Bd = 60 ; Brine draw minutes with #0 red, 80 if #00 white.
B2 = 5 ; Backwash 2 (minutes)
RR = 6 ; Rapid Rinse minutes
BF = 12 ; Brine fill minutes
FM = t1.2 (usual) ; t1.2 is default flow meter

 

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[Vladimir Zdorikov]

Thanks, Reach4.

I know there are a bunch of settings that I can just program in, but as an engineer (although not a water engineer), I wanted to also take this opportunity to understand how and why these parameters are derived and what are the tradeoffs in selecting them.

1) For example, what would be the tradeoff between 0.25gpm and 0.5gpm BLFC? Why would one be selected over the other? Does it only affect the amount of time it takes for the brine fill but nothing else?

2) How to choose between #0, #00, #1 etc. injector sizes for a generic configuration? I see some injector flow curves on the mfr website but how is one supposed to use that to derive which injector size(s) will work for some arbitrary configuration of softener?

3) Re DLFC, I had a typo -- meant to say 2.4, not 2.8 gpm. Is there any insight into how/why this size is selected? Or how it interacts with other choices?

Thanks!

 

[Reach4]

1) For example, what would be the tradeoff between 0.25gpm and 0.5gpm BLFC? Why would one be selected over the other? Does it only affect the amount of time it takes for the brine fill but nothing else?

Pretty much. With BF=12 with 0.25 blfc you inject 3 gallons. BF=6 could do that with 0.5 BLFC. There could be a time when you wanted to inject a different amount of salt. The 0.25 gives 0.25 gallon resolution.

2) How to choose between #0, #00, #1 etc. injector sizes for a generic configuration? I see some injector flow curves on the mfr website but how is one supposed to use that to derive which injector size(s) will work for some arbitrary configuration of softener?

You know how much water you are using. That grows by about 15% when the salt dissolves. You want the salt to be withdrawn in about 25% of the BD time. If BD=60, you want the draw to be in about 15, or up to 20 minutes. See the graphs in the service manual. Since the 7000 is not in bypass during BF, then expanding to 80 or 90 minutes for BF is no big deal. Expanding BD from 60 to 80 does leave the softener in bypass for 20 more minutes. Slightly slower flow is a tad more salt efficient. You mainly don't want the salt to pass too fast.

The 0.25 BLFC doubles brine fill (BF) time vs 0.5 gpm BLFC, but that does not increase the time softener is in bypass. The softener is not in bypass during BF.

3) Re DLFC, I had a typo -- meant to say 2.4, not 2.8 gpm. Is there any insight into how/why this size is selected? Or how it interacts with other choices?

Low enough to not blow resin out during backwash, even with colder than average water. Fast enough to fluff up the resin bed during backwash, and wash away any junk.

 

[Vladimir Zdorikov]

Thanks -- I now understand the BLFC sizing -- apart from the resolution/granularity, it's choice would seem to be partly dictated by the injector size.

I did a bunch of reading, including the injector flow charts in the service manual. I will use a #00 injector with BD = 80 minutes.

Above, when you say " Since the 7000 is not in bypass during BF, then expanding to 80 or 90 minutes for BF is no big deal.", did you really mean BF the second time it occurs in the sentence? BF is 12 minutes, not 80 or 90. The BD is 80 minutes -- I'm not sure if the system is in service or bypass during BD? (I do understand it is in service during BF...)

 

[Bannerman]

Since the 7000 is not in bypass during BF, then expanding to 80 or 90 minutes for BF is no big deal."

Yes, that should have said fewer minutes for the Brine Fill setting, not the 80-90 minutes for the Brine Draw setting.

Sizing the injector so BD will be 60 minutes duration is most common. There will be a slight efficiency gain when the brine travels more slowly through the resin bed so technically, there will be a slight benefit in using a smaller injector although you will continue to use the same salt (BF) and usable capacity settings either way.

 

[Reach4]

Thanks -- I now understand the BLFC sizing -- apart from the resolution/granularity, it's choice would seem to be partly dictated by the injector size.

I did a bunch of reading, including the injector flow charts in the service manual. I will use a #00 injector with BD = 80 minutes.

Above, when you say " Since the 7000 is not in bypass during BF, then expanding to 80 or 90 minutes for BF is no big deal.", did you really mean BF the second time it occurs in the sentence? BF is 12 minutes, not 80 or 90. The BD is 80 minutes -- I'm not sure if the system is in service or bypass during BD? (I do understand it is in service during BF...)

My fingers skipped a groove. I have edited #4. In BD, the softener is in bypass, but not in BF.

 

[Vladimir Zdorikov]

Thanks, Reach4. I have it programmed and working now.

Could you point to any material that explains the RS=cr; CR=0 settings?
I'm hoping to understand those settings better and the factory service manual is not clear...

 

[Reach4]

Could you point to any material that explains the RS=cr; CR=0 settings?
I'm hoping to understand those settings better and the factory service manual is not clear...

I think you are asking about the algorithm.

See https://terrylove.com/forums/index....g-advice-for-fleck-7000sxt.69050/#post-512626 paragraph 4.

On my softener, I went to a fixed reserve, because I was impatient waiting for the mystery algorithm to adjust.

 

[Vladimir Zdorikov]

Yes! I was asking about the algorithm used by the RS=cr setting. And also exactly what properties of the algorithm are tweaked by varuing the CR=0 parameter. I suppose no one has played with the latter.

Thanks for the pointers.

I tried to read up a bit on the B1, B2 and RR cycles but not sure I understood.

1) What determines the flow rate through the resin during these 3 cycles -- Injector Draw, Injector Rinse or Injector Total (i.e. Draw + Rinse).
2) Why is the RR setting needed at all?
3) In the BD cycle, what determines the flow rate -- I gather that the brine is sent through the resin at the Injector Draw flow rate for the initial part of the BD cycle, that seems clear enough. Then it appears that for the remainder of the BD cycle, just water is sent through the resin -- is that at Injector Rinse or Injector Total flow rate?

Note sure if there is a writeup somewhere that explains the above?

 

[Bannerman]

I tried to read up a bit on the B1, B2 and RR cycles but not sure I understood.

1) What determines the flow rate through the resin during these 3 cycles -- Injector Draw, Injector Rinse or Injector Total (i.e. Draw + Rinse).

The flow rate for both Backwash cycles and Rapid Rinse is governed by the flow rate of the Drain Line Flow Control (DLFC) restrictor that is installed within the drain assembly.

A 2nd BW cycle is beneficial when an ultra efficient salt setting is chosen. When using 6 lbs/ft3 or above, a 2nd BW is not necessary.

The flow rate for Brine Draw and Rinse (aka: Slow Rinse) is determined by which injector is installed. As the injector acts as a venturi, Slow Rinse flow through it will result in a vacuum on the Brine port which is sufficient to draw in brine from the brine tank at a specific flow rate. Both flow rates combined will be the injector total.

2) Why is the RR setting needed at all?

Rapid Rinse will recompact the resin bed as the spaces between resin granules had been expanded during the BW cycle. As water will always follow the path of least resistance, without compaction, the flow through the spaces will be less resistive so the water will have less contact with the resin and hardness leakage will therefore be higher through the softener. Although Service flow will be downward which will act to eventually recompact the resin, the RR cycle will ensure compaction at the specific flow rate needed which will reduce hardness leakage directly following each regeneration. Although 10-minutres is commonly programmed, a 6-minute RR setting will be typically sufficient.

3) In the BD cycle, what determines the flow rate ... Then it appears that for the remainder of the BD cycle, just water is sent through the resin -- is that at Injector Rinse or Injector Total flow rate?

Further to answer #1, Rinse flow will continue for the entire BD cycle which is typically 60-minutes duration. Once the brine within the brine tank is drawn down to the midpoint of the brine pickup screen at the bottom of the brine tank, the Air Check ball within the screen will no longer float. Once the ball comes to rest on the brine pickup opening, the opening will be closed off to prevent air from being drawn into the softener. Once the brine pickup opening is closed, the only flow through the injector will then be Rinse flow.

 

[Reach4]

1) What determines the flow rate through the resin during these 3 cycles -- Injector Draw, Injector Rinse or Injector Total (i.e. Draw + Rinse).

The injector-- see the graphs in the later pages of your service manual. The injectors are color coded.