Check My Settings for Fleck 5810 SXT

[Dmlaero]

I think I understand the principles, but I don't do this often so just looking for someone to check over my planned settings to make sure I didn't screw something up.

I've based this on a using a 7.2 lb/cuft salt dose to achieve 22,700 gr/cu-ft capacity which gives me a total system capacity of 56,700 grains. That will require an 18 lb salt dose which will be delivered by drawing 6 gal of brine, so at 0.25 gpm I need a BF time of 24 min. Hardness tested at 22 grains, so I'm estimating usage to be 6600 grains per day (4 people x 75 gal/day) which will will trigger a regen every 8.5 days.

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Resin Vol: 2.5 cu-ft
BLFC: 0.25 gpm
DLFC: 4.0 gpm
Injector: #3
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DF: GAL
VT: 5810
RF: dF2b
CT: Fd
C: 56.7
H: 22
RS: cr
DO: 21
RT: 2:00
B1: 7
BD: 60
B2: 3
RR: 7
BF: 24
FM: t1.2
RE: OFF
VR: OFF

 

[Reach4]

Very similar.
Using terrylove.com/forums/index.php?threads/fleck-9100-sxt-programming-settings.60651/ numbers.

System info (not programmed)
salt lb/cuft : 7.5 ; A choice ( efficiency vs capacity)
BLFC : 0.25 ; Brine Refill rate GPM
cubic ft resin : 2.5 ; Same as (nominal grains/32,000)
Raw hardness : 22 ; including iron etc
Estimated gal/day ; 300 ; 60 gal per person prediction (auto-tunes)
Est days/regen ; 7.68 ; presuming days each use estimated
I would have preferred a #1 or #2 rather than the #3 Injector - Yellow
I used H=25 due to high-hardness compensation factor.

Fleck 5810SXT Settings:
DF = Gal ; Units
VT = 5810 ; Valve type
RF = dF2b ; Downflow, Double Backwash
CT = Fd ; Meter Delayed regen trigger
C = 57.6 ; capacity in 1000 grains
H = 25 ; Hardness grains after comp factor
RS = cr ; Cr = base reserve on recent experience
DO = 30 ; Day Override (typ 30 if no iron/Mn)
RT = 2:00 ; Regen time (default 2 AM)
B1 = 5 ; Backwash 1 (minutes) [3...10]
Bd = 60 ; Brine draw minutes
B2 = 4 ; Backwash 2 (minutes)[3...10]
RR = 6 ; Rapid Rinse minutes
BF = 25 ; Brine fill minutes
FM = t1.2 (usual) ; t1.2 is default flow meter
RE = OFF ; Relay
VR = OFF ; ?

 

[Sponsor]

 

[Dmlaero]

Reach4, I appreciate your time to check things over. Looks like I had it figured about right.

 

[Dmlaero]

I would have preferred a #1 or #2 rather than the #3 Injector - Yellow

Even though I thought I had a grasp on this, I went down a rabbit hole thinking about your injector recommendations and dug into the 5810 SXT Installer Manual. For my 13"x54" / 2.5 cuft tank the 4.1.1 Injector/DLFC/BLFC-Valve configuration table indicates the #3 Yellow injector is correct, but my 0.25 gpm BLFC is undersized and should be 0.50 gpm.

Q1: If BLFC only controls refilling of the brine tank at the end of the cycle, then it would appear the only advantage to the 0.50 gpm over the 0.25 gpm BLFC is that it would cut the refill time in half. Is it that simple or am I missing something?

Moving on to the injector sizing...
The injector sizing formula in the manual indicates the total flow rate of the injector should be about 4x the resin volume per hour.

That means my 2.5 cuft of resin requires a total injector flow rate of 1.25 gpm. The #1 White injector has a total flow rate of ~1.1 gpm @ 65 psi and the #2 Blue injector has a total flow rate of ~1.6 gpm @ 65 psi. My current #3 Yellow injector has a total flow rate of ~1.9 gpm @ 65 psi. The #1 White or #2 Blue injectors are certainly closer to the 1.25 gpm target flow rate which corroborates your stated preferences for injector selection.

The #1 White injector will draw brine at ~0.32 gpm, so it will pull my target of 6 gal through in ~19 min.
The #2 Blue injector will draw brine at ~0.53 gpm, so it will pull my target of 6 gal through in ~11 min.
My current #3 Yellow injector will draw brine at ~0.60 gpm, so it will pull my target of 6 gal through in ~10 min.

Q2: Based on these times, I'm confused as to why the BD time is 60 minutes. Is that just so the brine has enough contact time with the resin for the ion exchange to occur?

Q3: The table recommends the #3 Yellow injector for a reason, so I'm curious what that reason is since the #2 Blue injector and #3 Yellow injector draw brine at nearly the same rate. Is the #3 Yellow injector specified because its higher total flow rate allows the brine to be more evenly distributed through the resin over the larger cross sectional area of a 13" tank?

Q4: A counter argument against the #3 Yellow injector and for the #2 Blue injector is that maybe the lower total flow rate of the #2 Blue injector would force less rinse water through the resin allowing the brine longer contact time?[/QUOTE]

 

[Bannerman]

the 0.25 gpm BLFC is that it would cut the refill time in half. Is it that simple

Yes.

I prefer 0.25 as it will allow finer adjustment of the salt amount used. Each 1-minute Brine Fill will signify 0.75 lbs salt vs 1.5 lbs salt for a 0.5 GPM BLFC.

For residential sized softeners, the injector will be typically sized to cause the needed volume of brine to be transferred from the brine tank to the media tank within approx 15-20 minutes. At that rate, the Brine Draw setting will be 60 minutes, thereby allowing the remaining 40-45 minutes for slow rinse flow to continue to leasurly push the brine through the resin bed and out to drain, causing the calcium, magnesium to be released from the resin to be flushed to drain along with rinsing away chloride and excess sodium from the brine.

Water treatment often involves compromise. A faster flowing injector can achieve a Brine Draw cycle that will be less than 60-minutes, but at the cost of reduced contact time, thereby resulting in less efficient exchange of sodium ions from the brine to the resin and therefore less hardness ions being released from the resin (= incomplete regeneration of resin capacity)

A lower flow injector will cause the brine draw cycle to take longer, allowing increased contact time with the resin, which will cause ion exchange to be slightly more thorough. While this will marginally improve the exchange efficiency, for a residential sized system, the slight amount of resulting additional capacity gained is not significant enough to allow programming a higher usable Capacity setting. With no significant additional capacity benefit, there will be little benefit to using a smaller injector and running the risk that regeneration may not have been completed before soft water will be required.

60 - 90 minutes Brine Draw time for a residential sized system is most often chosen as it usually provides the best balance of time and ion exchange efficiency.

 

[Reach4]

Q2: Based on these times, I'm confused as to why the BD time is 60 minutes. Is that just so the brine has enough contact time with the resin for the ion exchange to occur?

I don't know, other than I have not seen a recommendation for under 60 minutes. Math with a #2 would seem to call for about 41 minutes. Maybe the thought is that the faster slow rinse will be less laminar, so an extension of the rinse would be called for to get the salt with margin.