Pentair FLECK 3150 NXT Installer Manual page 33

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
slow rinse
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
fast rinse
To calculate the refill duration:
The refill flow rate is controlled by the refill controller (BLFC). The relation between the
BLFC size, the tank size and the resin volume is given in the valve specifications.
To calculate the refill duration:
T = V / Q
refill WB
Ref. MKT-IM-010 / C - 18.10.2019
Installer manual Fleck 3150 NXT/NXT2 - System sizing
x BV) / Q
BVsr SR
x BV) / Q
BVfr DLFC
BLFC
with:
T : slow rinse duration [min]
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:
T : fast rinse duration [min]
fast rinse
N : number of bed volume for fast rinse
BVfr
BV: bed volume [L]
Q : drain line flow controller size [L/min]
DLFC
with:
T : refill duration [min]
refill
V : Volume of water to be refill to prepare the
WB
brine [L]
Q : BLFC size [L/min]
BLFC
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