The manual provides installation steps, system sizing, sensor positioning, pressure settings, alarm functions and technical data for the Grundfos CU 301…
The Grundfos CU 301 controls pump speed to keep water pressure constant. It receives pressure sensor signals and communicates with the pump via mains‑borne signalling, eliminating extra wiring.
The guide covers system sizing, sensor placement, pre‑charge pressure, alarm handling, LED and fuse locations, wiring diagrams, and detailed technical specifications such as supply voltage, power consumption and environmental limits.
| Supply voltage | 1 × 100‑240 V –10%/+6%, 50/60 Hz |
|---|---|
| Power consumption | 5 W |
| Maximum backup fuse | 16 A |
| Maximum current consumption | 130 mA |
| Enclosure class | IP55 |
| Maximum cable length to pump | 200 m |
| Operating temperature range | –30 °C to +50 °C |
| Weight | 2.0 kg |
The pump starts automatically when the pressure drops at a rate of 0.1 bar/s or faster.
It must be set to 70 % of the desired pressure setting.
A permanently on service‑alarm indicator light shows that a factory‑set alarm value has been exceeded.
This manual explains 1 error code. Open a code for its meaning, causes and what to do: