Pentair FLECK 5812 XTR Installer Manual page 38

Installer Manual Fleck 5812 - XTR - System sizing
To calculate the brine draw duration:
Knowing the injector draw flow rate at the working pressure:
T = V / Q
brine draw brine
Note
Multiply the amount of salt in kg by 3 to get a approximation of the brine volume to draw.
To calculate slow rinse duration:
The volume of water to be used for slow rinse is given in the resin manufacturers specifications.
Generally speaking, it is advised that between 2 and 4 BV of water is used to perform the slow rinse
after brine draw. The slow rinse cycle allows brine to be pushed slowly through the resin bed, allowing
the resin to be in contact with brine for sufficient time and therefore to be regenerated.
Refer to the injector curve at the common working pressure to determine the slow rinse duration.
T = (N x BV) / Q
slow rinse BVsr
To calculate fast rinse duration:
The fast rinse is aimed at eliminating an excess of salt in the resin bed and also recompacting the
resin in the tank.
Depending on the valve type, the fast rinse flow rate is controlled by the DLFC or it has about the same
flow rate as in service. The fast rinse velocity can be the same as the service velocity, and the volume
of water to be used for the fast rinse is generally between 1 and 10 BV depending on the salt dosage.
T = (N x BV) / Q
fast rinse BVfr
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with:
draw
T
brine draw
V : brine volume to be drawn [L], see Refill calculation page 39
brine
Q : injection draw flow rate [L/min]
draw
with:
SR
T
slow rinse
N : number of bed volume for slow rinse
BVsr
BV: bed volume [L]
Q : injector slow rinse flow rate [L/min]
SR
with:
DLFC
T
fast rinse
N : number of bed volume for fast rinse
BVfr
BV: bed volume [L]
Q : drain line flow controller size [L/min]
DLFC
: brine draw duration [min]
: slow rinse duration [min]
: fast rinse duration [min]
Ref. MKT-IM-019 / E - 14.10.2019