Salt Amount Definition; Injector Flow Rates - Pentair FLECK 2750 NXT Installer Manual

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
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 BLFC
V = D x BV / S
WB Salt sol
Tip
When calculating the time required to draw the brine, take into account that the volume
of brine [Vbrine] will be 1.125 bigger than the volume of water refilled !
4.3

Salt amount definition

The salt settings are controlled through the controller programming. See Resin exchange capacity
and capacity of the unit [
4.4

Injector flow rates

The following graphics represent the injectors flow rate as a function of the inlet pressure for the
different injector sizes.
Ref. MKT-IM-026 / C - 15.12.2020
DLFC
→ Page 33].
Installer manual Fleck 2750 NXT/NXT2 - System sizing
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 brine
WB
[L]
Q : BLFC size [L/min]
BLFC
with:
V : Volume of water to be refill to prepare the brine
WB
[L]
D : Salt dosage per litre of resin [g/L]
Salt
BV: Bed volume [L]
S : 360g/L - Solubility of salt per litre of water
sol
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