Grundfos Booster Pump Repair London

Grundfos booster faults we see most

On Hydro sets the common calls are alarms from the CU control unit, a drive that trips on overload, a transducer reading incorrectly so the set never reaches its set point, and a duty pump that has lost performance through a worn chamber stack. On CR and CRE pumps a weeping mechanical seal is the classic failure, often after running dry or after long periods of cycling. On Scala and Home Booster units the faults are more often electronic — a failed sensor, a dry-run lockout, or a unit short cycling because the internal vessel has lost pre-charge.

• CU 3xx controller alarms and set point faults
• Drive overload trips and inverter faults
• Pressure transducer drift and failure
• Worn chamber stacks and lost pump head
• Mechanical seal leaks on CR and CRE bodies
• Dry-run lockouts and low inlet pressure alarms

How we diagnose Grundfos sets

We read the alarm log from the controller or drive before touching anything, because Grundfos records the fault history and it usually tells the story — repeated dry-run alarms point at the inlet, repeated overloads at a mechanical problem, and no alarms at all with poor pressure at a worn pump or a failed transducer. We then verify the reading against a calibrated gauge, test the accumulator pre-charge, and run each pump individually against its curve with the current measured.

• Controller and drive alarm history downloaded
• Transducer reading verified against a gauge
• Each pump run individually against its duty curve
• Accumulator pre-charge tested on a drained water side

Parts, spares and turnaround

We fit genuine Grundfos spares. Seal kits, shaft assemblies, chamber stacks, transducers, sensors and control boards for the common CR, CRE, Hydro, Scala and Home Booster ranges are readily available, and we carry the highest-turnover items on the van. Where a part needs ordering we make the set safe and, on twin or triple configurations, leave the building running on the healthy pumps while we wait.

Blocks, hotels and commercial plant rooms

Most of our Grundfos work is in residential blocks and commercial plant rooms where a failed booster means upper floors lose water. We attend same day, stabilise the supply, and follow up with a written report for the managing agent covering the fault, the repair and anything else in the plant room that is heading the same way. Sets we repair can be placed on a planned maintenance visit so pre-charge and changeover are checked before the next peak.

• Same-day emergency attendance for blocks and hotels
• Written reports for managing agents and facilities teams
• Planned maintenance offered after the repair