Fleck 6700 water softener: Brine sucks air, how does it work
_firs...@lr_dot_los-gatos_dot_ca.us
a separate brine tank (separate meaning that the cylindrical mineral
tank stands next to the brine tank, not in it). The brine tank is a
15x17 inch square tank. It has the usual grid at the bottom, and a
~3" diameter tube that contains the "air check valve" (long stick in
the tube, with a float, and the valve at the bottom). The softener
Fleck valve has an injector that's marked as "0.5 GPM = 1.5
lbs/minute; 2 GPM drain flow", which sounds very reasonable.
Our water is very hard, about 21 grains per gallon. The softener has
1 cuft of resin, with 32 kgrains capacity. Because we are on a
well/tank system, the water pressure cycles between 40 and 60 psi.
Typical water usage is around (or below) 100 gallons per day, which
means that regeneration should occur on average every two weeks.
There are a few things that I think I understand: The amount of brine
used during the brining/regeneration step is determined by the setting
of the tank fill/makeup step. In our case, we need about 10 lbs of
salt for each regeneration (we have 1 cuft of resin), which means
about 3.3 gallons of brins; round that up to 3.5 gallons for
simplicity. With a 0.5 gpm injector valve, that means that we have to
run the refill/makeup cycle for about 7 minutes.
This is my understanding of the various steps in the regeneration cycle:
- First comes a fast backwash cycle (in our case set for 10 minutes at
full drain flow), which is intended to flush out "dirt" from the
resin bed, since the resin bed effectively acts as a depth filter.
- Second is the actual brining / regeneration step. During this step,
at first brine is run into the resin bed, and once we're out of
brine, the resin bed is slowly rinsed. In our case, this step is
set for 60 minutes (which seems very reasonable, and agrees with the
recommendations of the resin manufacturer, Purolite).
- Third is the fast rinse cycle, again at full drain flow, again 10
minutes.
- Last is the tank fill / makeup cycle. It runs for 7 minutes, and
supposedly puts 3.5 gallons of water into the brine tank, which is
exactly the amount of brine that's going to be used in the next
regeneration cycle.
So far, so good. Did I get everything right above? Do the numbers
above sound right? Now come the parts I don't quite understand.
First, during the regeneration step, we measured the flow of water
coming out of the drain of the water softener. And it's quite
accurately 1 gallon per minute. This means that it will go through
all the brine (3.5 gallons) in 3.5 minutes, and then it starts sucking
air from the brine tank. It will then spend the remaining 56.5
minutes doing slow rinse, while continuously sucking air from the
brine tank. Is this right ? The particular reason I worry about it
is that I always thought that resin beds hate having air in them: it
shakes the resin loose, and the it gets flushed down the drain.
Second, what is the real purpose of the "air check valve" in the brine
tank? First, it is a shutoff valve: When the brine level gets way too
high in the brine tank (which could happen if the tank fill / makeup
cycle is set way too long), it shuts of the incoming water to the
brine tank. This is good, but a little redundant, as the brine tank
also has an overflow spigot that is plumbed to a drain. I would have
thought that the valve should also operate as an air check: During the
regeneration/brining step, as soon as we are out of brine, it shuts
the suction off, so no air gets sucked into the mineral tank.
Explanations from owners of Fleck-valve equipped softeners or other
experts would be very welcome.
--
The address in the header is invalid for obvious reasons. Please
reconstruct the address from the information below (look for _).
Ralph Becker-Szendy _firstname_@lr _dot_ los-gatos _dot_ ca.us
Gary Slusser
<_firstname_@lr_dot_los-gatos_dot_ca.us> wrote
> We have just intstalled a water softener with a Fleck 6700 valve, and
> a separate brine tank (separate meaning that the cylindrical mineral
> tank stands next to the brine tank, not in it). The brine tank is a
> 15x17 inch square tank. It has the usual grid at the bottom, and a
> ~3" diameter tube that contains the "air check valve" (long stick in
> the tube, with a float, and the valve at the bottom). The softener
> Fleck valve has an injector that's marked as "0.5 GPM = 1.5
> lbs/minute; 2 GPM drain flow", which sounds very reasonable.
The 3” tube is a brine well. The float and valve is a safety brine
system. The air check is on the bottom of the “long stick” gray tubing;
it is a ball (valve) in a cage.
> Our water is very hard, about 21 grains per gallon. The softener has
> 1 cuft of resin, with 32 kgrains capacity. Because we are on a
> well/tank system, the water pressure cycles between 40 and 60 psi.
> Typical water usage is around (or below) 100 gallons per day, which
> means that regeneration should occur on average every two weeks.
“around or below” isn’t good enough. Use 60 gallons per person per day.
Or if you use the people dial on the meter dial, you get 75 gpd/person.
> There are a few things that I think I understand: The amount of brine
> used during the brining/regeneration step is determined by the setting
> of the tank fill/makeup step. In our case, we need about 10 lbs of
> salt for each regeneration (we have 1 cuft of resin), which means
> about 3.3 gallons of brins; round that up to 3.5 gallons for
> simplicity. With a 0.5 gpm injector valve, that means that we have to
> run the refill/makeup cycle for about 7 minutes.
To fully regenerate 1 cuft of resin you need 15# of salt. Although you
don’t get very good efficiency with that setting so use 10 but then you
don’t get 30K of capacity, use 24K. We get 2.7# of salt per gallon of
water.
> This is my understanding of the various steps in the regeneration
cycle:
> - First comes a fast backwash cycle (in our case set for 10 minutes at
> full drain flow), which is intended to flush out "dirt" from the
> resin bed, since the resin bed effectively acts as a depth filter.
> - Second is the actual brining / regeneration step. During this step,
> at first brine is run into the resin bed, and once we're out of
> brine, the resin bed is slowly rinsed. In our case, this step is
> set for 60 minutes (which seems very reasonable, and agrees with the
> recommendations of the resin manufacturer, Purolite).
> - Third is the fast rinse cycle, again at full drain flow, again 10
> minutes.
The resin bed doesn’t act like a depth filter, and you don’t want it
too. Dirt and resin don’t get along well and your capacity will be
greatly reduced. I think you’ll find slow rinse is running all during
the Brine/Slow Rinse position, otherwise there is no way to get brine
out of the salt tank; no syphon action. And It’s Rinse, Backwash,
Brine/Slow Rinse, Rapid Rinse, Settle Rinse, Brine Refill IIRC. And the
safety brine system float should not be set where it stops the water
going to the tank before the brine valve in the control stops the flow.
> - Last is the tank fill / makeup cycle. It runs for 7 minutes, and
> supposedly puts 3.5 gallons of water into the brine tank, which is
> exactly the amount of brine that's going to be used in the next
> regeneration cycle.
>
> So far, so good. Did I get everything right above? Do the numbers
> above sound right? Now come the parts I don't quite understand.
>
> First, during the regeneration step, we measured the flow of water
> coming out of the drain of the water softener. And it's quite
> accurately 1 gallon per minute. This means that it will go through
> all the brine (3.5 gallons) in 3.5 minutes, and then it starts sucking
> air from the brine tank.
Your brine line flow control allows (point) .5 gpm/1.5# per minute, not
1 gpm. And you’re in Slow Rinse so you don’t get the DLFC (drain line
flow control into play during that position. The #500 air check in the
bottom of the brine well stops any air from being sucked after the brine
has been sucked down to its usable level. There is always about 2.5” of
water left in the tank; that is the height of the sir check off the
bottom of the tank but the safety brine system valve nay be set a ½” or
so higher so the air check cage is off the bottom of the salt tank.
> It will then spend the remaining 56.5
> minutes doing slow rinse, while continuously sucking air from the
> brine tank. Is this right ?
No, see above.
> The particular reason I worry about it
> is that I always thought that resin beds hate having air in them: it
> shakes the resin loose, and the it gets flushed down the drain.
A possibility but not during brining/slow rinse.
> Second, what is the real purpose of the "air check valve" in the brine
> tank?
You’re looking at the safety brine valve, a part number 2310, a black
plastic (Noryl) valve that the float controls when the water lifts the
float; it shuts off the brine refill water flow.
> First, it is a shutoff valve: When the brine level gets way too
> high in the brine tank (which could happen if the tank fill / makeup
> cycle is set way too long), it shuts of the incoming water to the
> brine tank. This is good, but a little redundant, as the brine tank
> also has an overflow spigot that is plumbed to a drain. I would have
> thought that the valve should also operate as an air check: During the
> regeneration/brining step, as soon as we are out of brine, it shuts
> the suction off, so no air gets sucked into the mineral tank.
ummmm if you get too much water due to the salt dosage setting, then
your salt tank is too small or you need a higher salt grid. So.... the
safety brine system is used to stop brine tank overflow, the salt tank
drain elbow is a safety in the event the safety brine system fails. To
use it you need to attach tubing to it and end it in a floor drain; it
is gravity fed, no water pressure. And they sometimes do fail. And one
cause is the brine valve (in the 6700 control valve) may fail to shut
off water to the brine line. Another cause would be if all the brine isn
’t sucked out, due to sucking air through loose brine line fittings and
other causes, and then the refill adds the water that should have been
used but wasn’t and the water level rises each incomplete regeneration
until the float shuts it off or the tank overflows.
> Explanations from owners of Fleck-valve equipped softeners or other
> experts would be very welcome.
Gary
Quality Water Associates