System Operation In Service (System 14-Demand Recall) - Pentair FLECK NXT TIMER Service Manual

SYSTEM OPERATION IN SERVICE
(SYSTEM 14-DEMAND RECALL)
The system operates as part of a multi-valve regeneration
system.
Each valve in the system will have an active flow meter input,
even in Standby.
The number of valves in service depends on the flow rate.
Examples of a Four-Unit System:
1. One Valve is in service at all times (the "primary valve").
1
In Service
(Primary Tank)
2. The total flow rate to the primary valve increased past
the first trip point programmed rate. The flow stayed past
the trip point delayed time. The next valve (least volume
remaining) changes from Standby to In Service. This valve
then splits the total flow between two meters.
1
First Trip Point
(Primary Valve)
Total Flow Split
Between Two Meters
3. The flow rate demand decreased below the first trip point.
The valve returns to Standby.
1
Flow Rate Demand
Below First Trip Point
(Primary Valve)
4. Total flow rate demand increased past a second trip point
programmed rate. The second and third valve (least volume
remaining) changes from Standby to In Service. The total
flow is split between the three meters.
1 2
Flow Split Between
Three Meters
2 3 4
Standby
2 3 4
In Service
Standby
2 3 4
Standby
3 4
Standby
5. The third valves returns to stand by as demand decreases
past the second trip point.
1 2
Flow Split Between
Two Meters
6. Valves return to stand by due to decreased total flow rate
and trip points programmed. The valve with the most
remaining volume will be the first to go into Standby.
1 2
Full Capacity 3/4 Capacity
4th in Standby 3rd in Standby
(Primary Valve)
7. The primary valve regenerates. The next valve with the least
remaining volume becomes the new primary valve. The
valve with the next least volume remaining will be the first
trip point programmed rate. Valves continue operating in
this order.
System Operation in Regeneration:
1 2
Full Capacity 3/4 Capacity
4th in Standby 3rd in Standby
If two valves are In Service and both reach
Volume Remaining = 0, the other two valves will shift from
Standby to In Service. The lead valve with
Volume Remaining = 0 will start regeneration. The second valve
with Volume Remaining = 0 will enter Standby. If flow increases
past the trip point a third valve needs to enter In Service. The
valve in Standby with Volume Remaining = 0 will shift into
In Service to maintain a steady flow. Operating for extended
periods in this mode may degrade the water quality.
3 4
Standby
3 4
1/2 Capacity 1/4 Capacity
2nd in Standby 1st in Standby
3 4
1/2 Capacity 1/4 Capacity
First Trip Point New Primary Tank
Programmed Rate
Fleck 3200 NXT • 5