Reading Between the Lines – Daily Rounds → Ammonia

Daily rounds, the mundane task of walking throughout your facility, logging all operating conditions, and noting any issues, typically on paper forms, and then turning them in to your supervisor or even just a drop box. This is a routine task for pretty much every industrial refrigeration technician that on the surface only “checks the box” for management, seems to be a waste of time and has little return on investment…but what if these could be more?

Lets take a look at what daily rounds are:

Daily rounds completed by refrigeration technicians typically involve a series of tasks and checks to ensure the proper functioning and performance of refrigeration systems. While specific routines may vary depending on the facility and equipment, here are some common daily rounds conducted by refrigeration technicians:

Visual Inspections: Refrigeration technicians perform visual inspections of the refrigeration system, checking for any signs of leaks, abnormal noise, or visual damage to equipment components such as compressors, condensers, evaporators, and piping.
Temperature and Pressure Checks: Monitoring and recording temperature and pressure readings at various points in the refrigeration system is essential. Technicians compare these readings to the expected values or setpoints to ensure proper system operation. This may involve checking temperatures in the evaporator, condenser, and suction/discharge lines, as well as monitoring refrigerant pressures.
Refrigerant Level Checks: Refrigeration technicians verify the refrigerant levels in the system to ensure they are within the recommended range. They may use sight glasses or refrigerant gauges to assess the refrigerant charge and make adjustments if necessary.
System Performance Evaluation: Technicians assess the overall performance of the refrigeration system by reviewing data trends and comparing them with established benchmarks or historical data. This includes analyzing energy consumption, refrigeration capacity, and system efficiency to identify any deviations or areas for improvement.
Control System Checks: Refrigeration technicians inspect and test the control systems, including temperature and pressure controllers, safety switches, and alarms. They ensure that the control settings are correct and troubleshoot any malfunctions or anomalies.
Oil Level and Quality Checks: For systems that utilize oil lubrication, technicians check the oil levels in compressors and assess the oil quality. They may perform oil sampling for analysis to detect any contaminants or signs of degradation.
Filter and Strainer Inspections: Inspecting and cleaning or replacing filters and strainers is part of routine maintenance. Technicians check for clogged or dirty filters and strainers, which can impede the flow of refrigerant or cause system inefficiencies.
Safety Checks: Refrigeration technicians verify the proper operation of safety devices, such as pressure relief valves, high-pressure switches, low-pressure switches, and temperature alarms. They ensure these safety mechanisms are functioning correctly to protect the system from potential hazards.
Documentation and Reporting: Technicians maintain accurate records of daily rounds, including readings, observations, and any maintenance or corrective actions taken. This documentation serves as a reference for tracking system performance and identifying recurring issues.
Communication: Refrigeration technicians may communicate with facility operators or supervisors, providing updates on system performance, any abnormalities detected, and maintenance recommendations.

Now, beyond the typical “put it in the filing cabinet” outcome, lets look at how you can better use this vital data:

Daily rounds completed by refrigeration technicians serve as a valuable foundation for implementing predictive maintenance programs in refrigeration systems. Here’s how these daily rounds can be utilized for predictive maintenance:

Data Collection: During daily rounds, technicians collect essential data such as temperature, pressure, and performance readings from the refrigeration system. This data forms the basis for monitoring equipment health and identifying potential issues. Technicians should use standardized forms or digital tools to record this information accurately and consistently.
Trend Analysis: By tracking and analyzing the collected data over time, technicians can identify patterns or trends that indicate deviations from normal operating conditions. This analysis helps identify early warning signs of potential equipment failures or inefficiencies. Technicians can compare current readings to historical data and established benchmarks to assess the system’s performance.
Condition Monitoring: Daily rounds provide an opportunity for technicians to visually inspect the equipment and identify any signs of wear, leaks, abnormal noise, or visual damage. These observations, along with the collected data, contribute to assessing the condition of the equipment. Technicians should document and report any abnormalities or potential issues discovered during their rounds.
Alarm and Safety Device Monitoring: Monitoring the proper operation of safety devices and alarms is crucial for predictive maintenance. Technicians should review the alarm logs and analyze any recurring alarms or system trips. These events can indicate underlying problems that require further investigation or maintenance.
Early Fault Detection: By analyzing the collected data and comparing it to established thresholds or equipment specifications, technicians can detect early signs of equipment faults or performance degradation. For example, a gradual increase in compressor discharge pressure or a decrease in evaporator temperature could indicate a potential issue. Technicians can then schedule proactive maintenance tasks or further diagnostic tests to address these emerging problems before they escalate.
Documentation and Analysis: Accurate and consistent documentation of daily rounds is vital for predictive maintenance programs. Technicians should record all observations, measurements, alarms, and maintenance actions taken. This documentation becomes a valuable historical reference for trend analysis, identifying recurring issues, and making data-driven decisions for maintenance planning.
Integration with CMMS or EAM Systems: To fully leverage the data collected during daily rounds, integrating it into Computerized Maintenance Management Systems (CMMS) or Enterprise Asset Management (EAM) systems is beneficial. This integration allows for centralized data management, automated data analysis, and generation of maintenance work orders based on predefined rules or thresholds.

By utilizing the data collected during daily rounds for trend analysis, condition monitoring, early fault detection, and documentation, refrigeration technicians can proactively identify and address equipment issues before they lead to unplanned downtime or failures. Predictive maintenance programs, built on this foundation, help optimize maintenance activities, extend equipment lifespan, improve system reliability, and reduce overall maintenance costs.

Analyzing and reviewing the data and trends that can be made from the information gather during daily rounds…or “reading between the lines”…can help with reactive troubleshooting and drive predictive maintenance. Finally, lets look at some basic trends and how they can be used on your refrigeration system:

Rising Trend in System Discharge Pressures: If technicians observe a consistent rising trend in system discharge pressures, it may indicate issues such as reduced heat transfer in the condenser (fouling or scale buildup) or the presence of non-condensible gases. In response, technicians can consider maintenance actions like checking and cleaning the condenser coils, ensuring proper airflow, verifying water treatment system operations, and purging non-condensible gases from the system.
Decreasing Trend in Evaporator Differential Temperatures: A decreasing trend in evaporator temperatures could suggest reduced cooling capacity, potential refrigerant leaks, or insufficient airflow. Technicians may respond by examining the evaporator coils for ice buildup, checking for refrigerant leaks, verifying proper fan operation, and ensuring adequate refrigerant charge.
Increasing Trend in Energy Consumption: Usually going hand-in-hand with higher discharge pressures, if there is a noticeable and consistent increasing trend in energy consumption, it may indicate reduced system efficiency or equipment malfunction. Technicians can respond by check compressor loading, VFD speeds, and slide valve positions, examining the performance Condenser and evaporator fan operation, checking for non-condensible or excessive water in the system, or even repairing damaged insulation.
Deviation from Setpoint Temperatures: When the recorded temperatures consistently deviate from the setpoint values, it suggests a potential control issue or malfunctioning sensors. Technicians can respond by calibrating temperature sensors, checking the performance of control valves or dampers, and verifying the integrity of the control system.
Alarming Trends or Spikes in System Alerts: If there is a sudden increase in system alarms or recurring alerts, it may indicate critical issues that require immediate attention. Technicians can respond by investigating the cause of the alarms, seeing if there is any relation between alarms, times, and condition of the system, and performing targeted maintenance or repairs to address the underlying problems.
Changes in Refrigerant Pressures: Significant and unexpected changes in refrigerant pressures, such as rapid fluctuations or pressure drops, may signify refrigerant leaks, issues with expansion/control valves, or restrictions in the refrigerant circuit. Technicians can respond by inspecting the system for leaks, checking the condition of valves and control devices, and conducting pressure tests to identify and repair any faults.

By identifying these trends and deviations from normal operating conditions, refrigeration technicians can take proactive maintenance actions to address potential problems promptly. This approach helps prevent equipment failures, optimize system performance, and minimize unplanned downtime in refrigeration systems. There are of course many more (probably unlimited) determinations that can be made by analyzing one, two, three, even multiple sets of data extracted from the daily rounds sheet. Doing the daily rounds (we know you already are), collecting and tracking this data (Exotic software or evening simply in MS Excel), and using the trends to address and get ahead of system problems is where we can make daily rounds far more meaningful and our systems more reliable.

Author: Ryan Reardon