Grundfos CMBE TWIN Duplex Booster System

The Grundfos CMBE TWIN is a packaged duplex booster: two CMBE pumps connected in parallel and mounted on a common base plate with a manifold set. Each CMBE pump carries a Grundfos integrated variable frequency drive and is delivered complete with five-way fitting, non-return valve, diaphragm tank, pressure sensor and pressure gauge. Both pumps run when a higher flow is needed to hold a constant pressure; one pump carries the load the rest of the time.

Cascade control adapts the system to consumption by switching pumps on or off and changing the speed of the pumps in operation, so the system runs with constant pressure using only the number of pumps required. Pump alternation distributes operating hours evenly — the system automatically starts the available pump with the lowest number of running hours since the last power-off. The premium-efficiency IE5 MGE motors need no external motor protection and run at 55 dB(A) or lower.

Hydraulics are stainless steel AISI 304 throughout — pump housing, sleeve, shaft, impellers and chambers — with an AISI 316 sensor fitting. CMBE TWIN is designed for flooded suction (maximum 3.28 ft of lift; not self-priming), handles liquid temperatures to 140°F, and is radio-enabled for Grundfos GO through the MI 301 module. Typical installations are apartment buildings, hospitals, hotels, small industrial plants and domestic fire suppression.

• Constant pressure — an integrated speed controller on each pump holds the set pressure; a pressure sensor signals the controller to speed up or slow down as consumption changes.
• Cascade control — pumps switch on and off automatically and run only as many as the demand needs, at the lowest energy cost.
• Pump alternation — operating hours are shared evenly; the pump with the fewest running hours starts first.
• Dry-running protection — on loss of inlet pressure or water the system stops and enters alarm mode, then attempts 5 restarts at 10-second intervals and 8 restarts at 5-minute intervals, repeating the cycle after 24 hours.
• No external motor protection — the MGE motor has built-in thermal protection against slow overload and blocking (TP 211, IEC 34.11).
• Robust stainless-steel design — AISI 304 hydraulics, stainless manifold set with ball valves and unions on a common base plate.
• Compact and quiet — noise level below 55 dB(A), lower still at controlled speed.
• Easy installation — connect the manifolds to the pipework, wire to the fuse box, set the pressure on the operating panel.
• Grundfos GO — wireless setup, status and operating data from a phone via the MI 301 radio module.

The Grundfos GO app does not connect to the system on its own — it needs the Grundfos MI 301 mobile interface, which is sold separately. The MI 301 is a pocket-sized module that pairs to your iOS or Android phone over Bluetooth Low Energy and then reaches the pumps by radio or infrared. Without it, the app cannot see the system — the CMBE TWIN still runs and the pressure set point is still entered on the operating panel, but everything below requires the module.

With the MI 301 connected, the free Grundfos GO app gives you setup, status overviews, technical product information and live operating parameters from your phone. Each CMBE pump on the TWIN connects to Grundfos GO through the module, so commissioning takes minutes and no laptop. Add the Grundfos MI 301 to your order.