Hydro Multi S

Summary

Product identification

The Grundfos Hydro Multi-S booster systems are designed for pressure boosting of clean water in applications such as blocks of flats, hotels, and schools.

These systems consist of two or three identical Grundfos CM, CMV, or CR pumps connected in parallel, mounted on a common base frame, and include a control cabinet with a motor-protective circuit breaker and an integrated controller. They are supplied as complete, pre-assembled, and tested systems, featuring suction and discharge manifolds, isolating valves, non-return valves, a pressure gauge, and pressure switches.

The systems operate at 50 Hz, with automatic pump operation controlled by individual pressure switches based on system demand.

Operating limits

• Maximum flow rate:
  • Up to 45 m³/h (CM and CMV pumps)
  • Up to 69 m³/h (CR pumps)
• Maximum operating pressure:
  • 10 bar (CM and CMV pumps)
  • 10/16 bar (CR pumps)
• Liquid temperature:
  • +5 to +40 °C (CM and CMV pumps)
  • +5 to +50 °C (CR pumps)
• Ambient temperature:
  • +5 to +60 °C (CM and CMV pumps, and CR pumps with motor sizes 1.1 kW to 5.5 kW)
  • +5 to +40 °C (CR pumps with motor sizes 0.37 kW to 0.75 kW)
• Voltage tolerance: -10 %/+10 %
• Relative air humidity: Max. 95 %
• Enclosure class (system): IP54

Electrical

• Supply voltage:
  • 1 x 220-240 V
  • 3 x 220-240/380-415 V
  • (For CR pumps, 1 x 220 V and 3 x 400 V options are also available)
• Frequency: 50 Hz
• Maximum power:
  • Up to 3.2 kW (CM and CMV pumps)
  • Up to 5.5 kW (CR pumps)
• Starting method: DOL (Direct On Line)
• Motor enclosure class: IP55 (for individual CM, CMV, CR motors)
• Motor insulation class: F
• Motor protection:
  • Motor-protective circuit breaker incorporated in the control cabinet.
  • Thermal overload relay (built-in for single-phase motors, and for all pumps via the control cabinet).
  • Built-in thermistor (PTC) for three-phase Grundfos motors of 3 kW and up.
  • Short-circuit protection by fuses.

Mechanical / hydraulic

• System Components:
  • Pumps: 2 or 3 per system
  • Discharge manifold: 1
  • Isolating valve: 2 per pump
  • Base frame: 1
  • Control cabinet: 1
  • Pressure gauge: 1
  • Pressure switch: 1 per pump
  • Stand: 1
  • Non-return valve: 1 per pump (installed on suction side of Hydro Multi-S CMV)
  • Screw cap: 2
  • Suction manifold: 1
  • Optional pressure switch: 1
• Pump Types:
  • CM pumps: Non-self-priming, multistage, end-suction centrifugal, horizontally mounted, close-coupled type.
  • CMV pumps: Non-self-priming, multistage, end-suction centrifugal, vertically mounted, close-coupled type.
  • CR pumps: Non-self-priming, vertical, multistage centrifugal, with in-line suction and discharge ports.
• Shaft Seals:
  • CM and CMV pumps: Maintenance-free mechanical O-ring shaft seal (AQQE).
  • CR pumps: Maintenance-free mechanical HQQE shaft seal of the cartridge type.
• Materials:
  • CM-A (Galvanised-steel base frame and manifolds): Suction and discharge parts EN-GJL-200; Pump shaft, impellers/chambers EN 1.4301/AISI 304.
  • CM-I (Stainless-steel base frame and manifolds): Suction and discharge parts, pump shaft, impellers/chambers EN 1.4301/AISI 304.
  • CMV (Galvanised-steel base frame and manifolds): Suction and discharge parts EN-GJL-200; Pump shaft, impellers/chambers EN 1.4301/AISI 304.
  • CR (All stainless steel base frame and manifolds): Pump head, base EN-JL1030/ASTM 25B; Shaft stainless steel (1.4401/AISI 316 for CR 3, 5; 1.4057/AISI 431 for CR 10, 15); Impeller, chamber, sleeve EN 1.4301/AISI 304; Neck ring PTFE; Rubber parts EPDM.
• Pipework Connections: Available with Rp 2, Rp 2 1/2, or Rp 3 connections, depending on the specific pump model.
• Installation:
  • Must be installed in a well-ventilated room; not suitable for outdoor installation.
  • Sufficient clearance required around the system for operation.
  • Pipes connected to the booster system must be of adequate size; expansion joints should be fitted in the suction and discharge manifolds.
  • Pipe supports are advisable on both suction and discharge sides.
  • Position the booster system on an even and solid surface.
  • Hydro Multi-S systems with CM pumps must be bolted to the floor.
  • Hydro Multi-S systems with CMV or CR pumps can either be bolted to the floor or fitted with machine shoes.
• Diaphragm Tank: A suitable diaphragm tank must be fitted to ensure reliable automatic operation, connected to the discharge manifold or pipeline. See the official PDF for exact tabulated values for recommended tank sizes based on pump type and number of pumps.

Functions

The Hydro Multi-S systems offer the following features:

• Automatic cascade control of pumps by means of two or three pressure switches.
• Automatic pump changeover at any start/stop cycle.
• Automatic isolation of a pump if it is in a fault status.
• Automatic resetting of dry-running fault.
• Manual resetting of overload trip.
• Possibility of emergency operation.
• Pump and system protection features:
  • Short-circuit protection by fuses.
  • Motor protection by means of a thermal overload relay.
  • Dry-running protection by means of a pressure switch or level switch (optional on Hydro Multi-S CMV).
  • Start-up delay between pumps to prevent simultaneous start-up.

Accessories

• Diaphragm Tanks: Available in 10 bar and 16 bar versions, with capacities ranging from 8 litres to 300 litres. Connections include G 3/4, G 1, and DN 50.
• Dry-running Protection: Available as an electrode relay (without electrodes and electrode cable).
• Audible Alarm: Sounds in case of a system alarm, available with sound pressure levels of 80 dB(A) or 100 dB(A) (located in the control cabinet).
• Machine Shoes: Reduce vibrations and allow for height adjustment (± 20 mm). Available for CM 3/5, CMV 3/5, CR 3/5, and CM 10, CR 10/15 models. Note: Hydro Multi-S with CM pumps must be bolted directly to the floor and cannot use machine shoes.

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions from the complete OEM PDF datasheet. Contractual data must always match the specific OEM PDF revision used for the project.

Official datasheet (PDF)

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