Detecting misalignment in chiller water pump with vibration analysis in a pharmaceutical manufacturing plant located in Ireland.

This chiller water pump is critical in the HVAC System, which is designed to provide thermal comfort and acceptable indoor air quality in the manufacturing areas.

The Eastway team have been supporting the on-site maintenance personnel in this plant since 2012, carrying out a range of condition monitoring services as well as other services such as balancing and alignment.

Case Description

During the vibration survey in May 2020, high vibration velocity values (mm/s RMS) were recorded at the chiller water pump and motor test points.  Vibration data was collected on-site using a portable vibration data collector.  See Figure 1. for the motor non-drive end velocity (mm/s RMS) trend showing this unexpected increase in vibration values.

                                   Figure 1. Velocity (mm/s RMS) trend from motor non-drive end test point

Recommended Action

Further analysis of the vibration data from the motor and pump was completed by the Eastway condition monitoring team. For this analysis, the velocity (mm/s RMS), acceleration (g RMS) and demodulation (g RMS) data were examined.

During the analysis a 1X high in the horizontal direction was observed, the vibration pattern indicated frequencies related with misalignment. Figure 2. displays a sample from the motor non-drive end velocity FFT spectrum (mm/s) showing a dominant 1X peak and presence of 2X, 3X, etc. Based on the increasing vibration trend at the motor and pump, it was recommended to check the shaft alignment at the motor/pump at next downtime to prevent further damage.

Figure 2. Motor non-drive end velocity FFT spectrum (mm/s) showing a dominant 1X peak

Action Taken

Following this recommendation, a downtime window for the chiller water pump was planned with the plant production team. Eastway was selected to carried out the shaft alignment on the unit.

Before attempting the shaft alignment, Eastway took cross-channel phase readings across different points of the unit. This analysis confirmed that the main cause of the high vibration levels was misalignment.

After the alignment completion, the vibration was tested across the unit and a significant reduction in vibration values was found at the motor and pump and they have remained at low magnitudes since. See Figure 5. for the pump drive end – velocity (mm/s) trend showing this decrease in vibration values.

Figure 3. Velocity (mm/s RMS) trend from pump drive end test point


This case prevented the premature deterioration of the bearings, seals, shafts, and coupling of the water pump by using vibration analysis. Thus, in addition to identifying problems and dramatically reducing downtime, the detection also extended the life of components and allowed for maintenance work to be carried out in an efficient way.

Table 1. below displays the importance of having predictive maintenance in place to detect failures, in this case detecting misalignment in chiller water pump with vibration analysis, allowing corrections to be carried out before costly system failures occur.

Next Vibration Analysis case study: Detecting Compressor Motor Bearing Wear with Vibration Analysis