Operating Modes; Manual Operation; Automatic Operation; Dry-Running Protection - Grundfos Hydro Multi-S Instrucciones De Instalación Y Funcionamiento

9. Operating modes

The operating mode of each pump can be selected with the
dedicated buttons for "Automatic operation", "Stop" and "Manual
operation" as described in section

9.1 Manual operation

Manual operation is generally used during commissioning, testing
or for maintenance and service purposes.
To enable manual operation, press and hold down the button for
manual operation.
The button for manual operation has no
Note permanent position. Therefore, keep the button
pressed during the test cycle.

9.2 Automatic operation

When this operating mode is selected, the pumps will operate
automatically according to the system requirements, e.g. the
pressures set on the pressure switches.
• When a tap is opened, water will be drawn from the diaphragm
tank, if fitted, until the tank is empty.
• When the pressure drops to the first cut-in pressure, the first
pump will start.
• If the consumption is still increasing, more pumps will be cut in
until the performance of the pumps in operation corresponds
to the requirements.
• When the water consumption decreases, the discharge
pressure will rise to the first cut-out pressure, the pressure
switch will cut out, and one pump will be stopped.
• If the consumption is still decreasing, more pumps will be cut
out until the last pump stops.

9.3 Dry-running protection

The Hydro Multi-S incorporates dry-running protection to protect
the pumps from running dry. The dry-running protection is
activated by a pressure switch or a level switch connected on the
suction side and then connected to the control cabinet.
Each pressure switch will be related to one pump
Note only and not necessarily to the same pump when
the pumps alternate after each cycle.
7. Control panel.

9.4 Emergency operation

Warning
The terminals and the cables connected before
the mains switch will remain powered even if the
switch is in off position.
Emergency operation should only be used in
case of emergency and only for short periods of
time.
Caution
A defective circuit board should always be
replaced by a new one. Contact Grundfos for a
new circuit board.
All functions of the Hydro Multi-S are controlled by an electronic
circuit board inside the control cabinet. If the circuit board should
fail, it is possible to avoid system stops. For three-phase booster
systems, it is possible to bypass the circuit board and operate the
booster system by using the pressure switches only.
To establish emergency operation, proceed as follows:
1. Switch off the power supply, and open the control cabinet.
2. Remove the control connector from its original position,
see fig. 5, pos. A, and insert the connector in the emergency
position, see fig. 5, pos. B.
3. Close the control cabinet, and switch on the power supply.
B
A
Fig. 5 Electronic circuit board

10. Functions

The Hydro Multi-S offers the following features:
• Automatic cascade control of pumps by means of two or three
pressure switches.
• Automatic pump changeover at any start/stop cycle.
• If a pump is in fault status, it is automatically taken out of
operation.
• Automatic resetting of dry-running fault status.
• Manual resetting of tripped-overload status.
• Pump and system protection:
– Short-circuit protection by means of fuses.
– Motor protection by means of a thermal overload relay.
– Dry-running protection by means of an additional pressure
switch or level switch.
– Start-up delay between two pumps: Prevents simultaneous
start-up of more than one pump.
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