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14. NXT Pro and pressure tank fitment
The nXt Pro controller behaves as a pressure controller in Mode 1 and as a pressure switch
in Mode 2
As supplied, the controller has a 0.3 litre pressure
accumulator threaded onto the rear of the unit Removing
the OEM tank exposes an internal 1" BSPF thread which
allows the user to thread a 2l pressure directly to the
controller or to connect larger pressure vessels via a
flexible hose.
Maximum size for direct fitment
– 2 litre
Mode 1
A pressure controller minimises pump cycling by keeping the pump running until the flow
drops below 0.9 lpm so it cannot be said that a pressure vessel is essential.
Most systems suffer from small water losses (dripping taps, leaking cisterns, feeding low
demand items such as ice makers or Reverse Osmosis filtration units)
the addition of a 2, 8
or 18 litre tank is strongly encouraged
Fitting a pressure tank will reduce the number of pump starts giving a number of benefits:
•
Power saving (reduced power bill!)
•
Longer pump life
•
Reduced noise
Mode 2
As with all pressure switches,
a suitably sized
pressure vessel MUST be added to the
system to prevent the pump from cycling
.
Typically surface mounted pumps up to 2.2kW
should start less than 30 times per hour.
Pressure tanks should never hold more than 1/3
of their total volume as water.
Manufacturer’s recommend the gas pressure in
the tank to be 66% of the maximum system
pressure.
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