Hydro Multi B

Summary

Product Identification

The Grundfos Hydro Multi-B is a booster system designed to maintain constant pressure despite flow fluctuations. It is suitable for clean-water pressure-boosting applications in buildings where the mains water supply is insufficient or unstable, such as office buildings, blocks of flats, hotels, shopping centres, hospitals, and schools.

Standard Hydro Multi-B systems consist of two or three CM(E) pumps coupled in parallel, mounted on a common base frame with necessary fittings and a control cabinet. The system features a CU 323 controller for automatic cascade control.

Two control variants are available:

• Hydro Multi-B E: Features two or three speed-controlled CME pumps.
• Hydro Multi-B ES: Features one speed-controlled CME pump and one or two mains-operated CM pumps.

Operating Limits

• Maximum operating pressure: 16 bar
• Liquid temperature: 0 °C to +60 °C
• Ambient temperature: 0 °C to +40 °C
• Relative air humidity: Maximum 95 %

Feed Water

The system is designed for clean-water pressure-boosting applications.

Mechanical / Hydraulic

• Number of pumps: 2 or 3
• Pump types: Grundfos CM (mains-operated) and CME (integrated frequency converter) non-self-priming, horizontal, multistage, end-suction centrifugal pumps.
• Shaft seal: AQQE (SiC/SiC/EPDM)
• Materials:
  • CM(E) 3 to CM(E) 25 pumps: Stainless steel (EN/DIN 1.4301/AISI 304)
  • Manifold: Stainless steel (standard), Galvanised steel (optional in some countries)
• Pipework connection:
  • Union: R 2 to R 2 1/2
  • DIN flange: DN 80 to DN 100
• Diaphragm tank: One diaphragm tank is included, with 35-litre tanks delivered separately for some models.
• Maximum head:
  • Hydro Multi-B E: 120 m
  • Hydro Multi-B ES: 125 m
• Flow rate: 0 to 108 m³/h for both E and ES variants.
• Dimensions and weights: Dimensional sketches are provided for two and three pump systems. Exact dimensions (L, W, W1, W2, H1, H2) and weights vary significantly by pump type, number of pumps, and voltage. See the official PDF for exact tabulated values.

Electrical

• Motor power: 0.55 to 7.5 kW
• Supply voltage:
  • U1: 3 x 380-415 V -10 %/+10 %, N, PE
  • U2: 3 x 380-415 V -5 %/+5 %, PE
• Frequency: 50/60 Hz
• Enclosure class: IP54
• Protection: ES systems should be protected against phase failure.

Functions

The Hydro Multi-B systems offer the following functions via the CU 323 control panel:

• Constant-pressure control: Maintains constant pressure by adjusting pump speed and/or number of pumps.
• Pump cascade control: Automatically ensures the required number of pumps run efficiently.
• Automatic pump changeover: Ensures equal operating hours and starts a standby pump if a running pump fails.
• Stop function/Low-flow mode: Stops the last pump or switches to on/off control during very low or no consumption to prevent liquid heating.
• Integrated frequency converter: Standard in all systems, with at least one CME pump having an integrated speed-controlled motor.
• Water shortage protection (optional): Monitors inlet pressure or tank level and stops pumps if too low. Can be reset manually or automatically.
• Standby pumps (optional): Allows limiting maximum performance by designating one or more pumps as standby.
• Tank-filling software (optional): Controls pumps for safe and controlled tank filling.
• Digital input for external start/stop relay: Standard.
• Alarm and operation outputs: Standard.
• Motor protection: Standard.
• Maximum pressure protection: Standard (for constant-pressure boosting).
• Protection in case of sensor fault: Standard.
• Protection in case of high tank level: Standard (for tank filling).
• Button lock function: Standard.
• Communication options (optional):
  • CIM module (Communication Interface Module) for SCADA or mobile phone communication.
  • External GENIbus connection.
• Redundant primary sensor (optional): Available for enhanced reliability.

Performance

Performance range charts are provided for 50 Hz, 60 Hz, and 50/60 Hz operations, illustrating head (H in m) versus flow rate (Q in m³/h) for various CM(E) pump configurations (1, 2, or 3 pumps in operation). These curves adhere to ISO 9906 Annex A tolerances, are based on airless water at +20 °C with a kinematic viscosity of 1 mm²/s (1 cSt), and apply to fixed speeds of 2900 min⁻¹ (50 Hz) and 3480 min⁻¹ (60 Hz). See the official PDF for detailed performance curves and selection guidance.

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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 on the project.

Official datasheet (PDF)

Lenntech datasheet mirror