Adjusting The Pressure Switch - Grundfos JP PS Notice D'installation Et De Fonctionnement

4.2.2.1 Maximum system pressure
Make sure that the system in which the pump is installed
is designed for the maximum pump pressure.
The maximum inlet pressure depends on the feet of head at the
actual duty point. The sum of the inlet pressure and the feet of head
must not exceed the maximum system pressure.
We recommend installing a pressure-relief valve to protect the
pump so that the outlet pressure does not exceed the maximum
system pressure.
Related information
10.1 Operating conditions
10.3 Inlet pressure
4.2.2.2 Inlet and outlet pipes
Please follow these general precautions when connecting the inlet
and outlet pipes.
Do not let the pump support the pipes. Use pipe hangers
or other supports at proper intervals to provide pipe
support near the pump.
The internal diameter of the pipes must never be smaller
than the diameter of the pump ports.
• Install the pipes so that air pockets are avoided, especially on
the inlet side of the pump.
• Use eccentric reducers with the tapered side down.
• Make sure the pipes are as straight as possible to avoid
unnecessary bends and fittings. We recommend long-radius 90
° pipe bends to decrease friction loss.
• Run the inlet pipe as direct as possible and, ideally, make sure
the length is at least ten times the pipe diameter.
• If possible, run a horizontal inlet line. We recommend a gradual
upward slope for pumps operating in suction-lift conditions, and
a gradual downward slope for pumps operating in positive inlet-
pressure conditions.
• A short pipe must be of the same diameter as the inlet port or
larger.
• A long pipe must be one or two sizes larger than the inlet port,
depending on the length.
Recommended pipe installation to avoid friction and air pockets
Correct pipe sizing for connection to the pump inlet or outlet

4.2.2.3 Adjusting the pressure switch

See the wiring diagram on the inside of the protective
cover on the pressure switch.
A full turn of the adjustment nut is 2.5 psi.
1. Turn the larger nut clockwise to raise the cut-on/cut-off
pressures.
2. Turn the smaller clockwise to raise the the cut-off pressure
only.
7