GrundfosBooster Pumps

Sizing comes down to two figures: the flow rate you need (litres per minute, based on the number of outlets used simultaneously) and the boost pressure required to overcome your incoming main's shortfall. As a rule of thumb, a single CM pump suits most domestic properties, while twin or triple configurations are used where higher flow or built-in redundancy is needed, such as multi-occupancy buildings. If you're unsure, get your incoming mains pressure and peak demand checked before ordering.

A single pump configuration is the most compact option and suits typical domestic cold-water boosting. Twin and triple set-ups run pumps in parallel, giving greater flow capacity and duty-standby operation, so if one pump needs servicing or fails, the others keep the supply running. Twin and triple units are generally specified for commercial buildings, larger HMOs, or anywhere continuity of supply is critical.

Yes, every Grundfos CM pump in this range is fully WRAS-approved, meaning it meets the UK Water Regulations Advisory Scheme's requirements for use on a potable water supply. This is essential where the pump is boosting drinking water rather than non-potable or rainwater harvesting systems, and it's what water suppliers and building control will expect to see documented.

The RS inverter paired with each Grundfos booster pump controls motor speed to match real-time demand, rather than running flat-out or cycling on/off, which improves energy efficiency and reduces wear. It also gives you a readout of pump performance, flags error codes for diagnostics, and lets you adjust set pressure and control parameters without needing to strip the unit down.

You'll need a suitable electrical supply matched to the pump and inverter's specification, adequate incoming water pressure and flow to feed the pump (boosters increase pressure, they don't create water from nothing), and enough space with drainage nearby in case of maintenance or leaks. Most installations are straightforward for a competent plumber or electrician, but on-mains boosting also needs to comply with your water company's byelaws, so check before connecting.

These horizontal multistage pumps are widely used for cold-water pressure boosting where incoming mains pressure is too low for upper-floor bathrooms, power showers, or multi-outlet demand. They're equally suited to domestic homes, blocks of flats, and light commercial premises, and their compact modular design makes them a practical retrofit where plant room space is limited.