For successful Preventative Maintenance, begin with a baseline, then adjust as needed

Preventative maintenance (PM) is essential for any organization that relies on machinery to operate at high level of efficiency. Creating an effective PM plan requires a deep understanding of the equipment application and operating environment.

Successful PM starts with building a baseline set of requirements for an ongoing program. A PM baseline sets a benchmark, perhaps on paper or more often in a computerized maintenance program, that allows for easy tracking – automated reminders, checklists, or forms – of when a maintenance action is likely needed. For example, a baseline might include a three-month reminder to clean or replace a drying filter to prevent a dip in equipment performance.

In most situations, under “typical” operating conditions, the maintenance guidelines offered by manufacturers are sufficient to help form baseline maintenance plans. However, processors who confront any of a series of harsh equipment operating or environmental conditions may find that they have to develop a PM baseline that is “maintenance heavy,” with much more frequent and intensive maintenance requirements.

“Maintenance heavy” situations

Regrind dust.  Equipment in any facility that handles and processes regrind is likely to need much more intensive maintenance due to the increased load of dirt and dust. Though processors don’t do a lot of material drying that involves regrind, a steady supply of ambient air – and the dust it contains – circulates constantly through dryer filters.  And, as it accumulates on filters, it can affect the performance of both the material drying circuit and the desiccant-recharge circuit. So, those filters must be kept clean if dryers are to maintain consistent dew-point and temperature performance.

Frequent PM may be even more important for vacuum pumps used in material conveying systems, because they, along with other system components, are directly exposed to dusty regrind materials.  The pumps are constantly pulling in this dusty air, drawing it all the way back to the dust collectors and their own internal filters. As filters become blocked, conveying system performance drops off, pumps overheat, and eventually shut down.  Equipment in extremely dusty conditions may need baseline maintenance on a filters every day.

Lousy water. A lot of processors have water problems involving low-quality, poor filtration, or insufficient treatment of marginal water supplies.  Poor quality water usually hits heat-transfer equipment, especially chillers. To help ensure a smooth flow of water through sensitive internal components, chillers rely on strainers to capture minerals, debris, or particulates in the incoming water stream, some of which are quite small.  These strainers can get plugged up, so they’ve got to be pulled out regularly and cleaned.  Otherwise, water flow to the chillers’ evaporator becomes limited, causing heat transfer problems and unstable process-coolant temperatures. In extreme cases, chillers may even trip off line due to “low flow” conditions.

Poor quality water can also cause strainers to fail.  Improper cleaning of strainers, or material buildup on strainers can cause the strainers to physically break down, creating openings that allow contaminants to pass into the chiller. Such debris can reduce internal flows or cause plugging as it accumulates in the smaller channels and passages in the evaporator. It’s not uncommon to see evaporators where low internal flows or blockages cause passages to freeze up and breach, which can seriously damage the entire refrigeration circuit and necessitate major repairs.  So again, it’s important to prevent all this by setting a PM baseline that calls for regularly removing and cleaning these relatively basket- and wye-type strainers.

Another water-related chiller concern involves the temperature and flow sensors within chillers, which also need regular inspection and cleaning.  Should debris or sludge be allowed to build up on these very small sensors, which may be just a ¼ in in size, your chiller may begin to issue some unusual or inaccurate readings, again indicating potential problems. Dirty or blocked sensors can affect chiller lines of any size – from 1-1/2 inch lines serving smaller units to 10-inch lines serving really large units.

Moist air.  Compressed air drives key components of process equipment – valves on loaders, valves on dust collectors, blender air cylinders, vacuum pump idle-mode valves, and many more. And to drive pneumatic components reliably, you need a compressed air supply that is both ample and dry.

Having excessive moisture in compressed air is a frequent and serious maintenance problem, because it accelerates ordinary wear, breakdown, rust, and corrosion in the surfaces, seals, and operating components of a host of equipment. What causes the problem?  Most likely, you didn’t size your compressed-air dryer large enough initially, or that you’ve added additional compressor capacity to your system.  Note that moisture related problems are aggravated in warmer plant environments.

Three ways to set up a maintenance baseline

So, whether your plant is affected by any of the above problems or not, there are three typical ways to establish a PM baseline. Note that a well-matched preventative maintenance plan can yield significant cost savings in the long run, but every plan must strike a sometimes-delicate balance. A baseline that’s too aggressive risks replacing parts prematurely and incurring unnecessary expenses, while a plan that’s too relaxed can contribute to unexpected equipment failures, costly emergency repairs, and downtime.

There’s really only one way to see if you’re striking the balance:  by evaluating how well your equipment is running.  Be on the lookout for changes in equipment efficiency:  higher conveying pump vacuum levels or rising pump temperatures, unsteady drying dewpoints, unusual chiller flow readings, reduced conveying throughputs, relief valve triggers, or any of dozens more. Obviously, the key is observing and maintaining – pulling filters, cleaning sensors, identifying and repairing leaks, etc. Regular maintenance activities like these should tell you what you need to know, e.g., that you need a two-week threshold for filter cleanings, or that chiller lines may need cleaning and flushing.

There are three basic ways that processors develop PM baselines:

  1. Trial and Error Approach:  If you, or your equipment, are somewhat new, you can begin to establish a baseline by trial-and-error – a given period of detailed observation of equipment that’s operating at full capacity. During this phase, it’s advisable to start with a more aggressive maintenance schedule and gradually transition towards a more relaxed one, finding a comfortable middle ground. This approach is particularly valuable when the equipment operates in a demanding environment, as it allows for adjustments based on real-world performance.  In any trial period, vigilance is essential – observations, record keeping, data logging – to pinpoint when different equipment begins to experience operational changes that could indicate a maintenance threshold or suggest additional measures to improve the operating environment.
  2. Manufacturer Assessment: Another valuable approach is to enlist the help of the equipment manufacturer or a specialized service provider. Often, processors reach out for help after they’ve had a maintenance problem, or when new maintenance personnel are unsure of equipment status and need a “reset” on the PM baseline. A growing number of equipment companies offer comprehensive assessments, such as Conair’s “MachineHealth™ Assessment.” This assessment brings in a skilled technician to compare maintenance logs to the current equipment condition and offer tailored maintenance recommendations. At the same time, the assessment provides a thorough, checklist-based inspection and offers repairs needed to leave the equipment in optimal condition. An assessment report provides a detailed record of findings, including suggested maintenance benchmarks, and is supplied on digital forms to simplify transfer of information to local maintenance software. Customers who wish to limit their PM responsibilities may also enter into service agreements with manufacturers. Ordinarily, these provide for regular visits and maintenance assessments, and produce maintenance, repair, and parts recommendations for follow-up by the customer. While equipment assessments and service agreements require additional customer investment, most customers see their value as a means of avoiding unexpected downtime and emergency repairs. Many find that creating an annual PM schedule or service agreement cost less, on an annual basis, than a single day of downtime.
  3. Automated System Monitoring: While establishing a PM baseline provides a solid framework for maintenance, manually logging data, even on a computer, can be a time-consuming process. Now, there is an alternative approach – automated system monitoring – that uses Industry 4.0 tools, such as Conair’s SmartServices®, to track, record, and analyze real-time equipment data and trends. Such tools also allow you to set digital thresholds on key equipment performance parameters or differentials/changes in temperature, vibration, throughput, pressure, flow rates, and more). The system triggers trigger automated notifications if the parameters stray beyond threshold values.  Solutions like this move processors toward predictive maintenance approaches by signaling early warning signs for maintenance actions when the run capacity of the equipment begins to be compromised. The SmartServices software not only works with computerized equipment controls, but can also monitor hardwired equipment – pumps, motors, dust collectors and more – by way of add-on, digital sensor kits that capture and communicate equipment data to the SmartServices cloud-based platform.  The monitoring and maintenance capabilities of Industry 4.0 solutions like this are almost limitless.

No matter what approach you adopt, establishing a maintenance baseline serves as the foundation for a well-planned preventative maintenance schedule. In conjunction with this schedule, meticulous maintenance logs should be maintained, detailing all tasks performed. Together, these practices enhance equipment performance, minimize downtime, and align maintenance efforts with performance objectives.


In the world of preventative maintenance, one size does not fit all. To ensure the longevity and efficiency of your equipment, it’s imperative to create a maintenance plan custom to your specific application and needs. By establishing a baseline through trial and error or manufacturer assessments, you can strike the right balance between proactive maintenance and cost-effectiveness, ultimately maximizing equipment uptime and performance. Additionally, maintaining detailed records of your maintenance activities will provide a valuable resource for continuous improvement and long-term success.

Dirty, Dusty Air.  Hard-working air filters and screens are vital for protecting vacuum pumps, loaders and receivers, and other material handling equipment from choking regrind dust and angel hair.  However, if they are not cleaned on a regular basis, clogged screens and filters like those shown in an actual processing plant can lead critical components to overheat, trip-off line and potentially, to fail and require significant repairs.  In dusty environments, filter maintenance is a top PM priority.

Dirty Heat Exchanger. Darkened and caked with impurities, this air-to-air aftercooler can no longer efficiently dissipate heat.  As a result, it is less-than-efficient at providing the air-to-air heat exchange that is essential to cool the desiccant wheel of a Conair desiccant dryer and enable maximum moisture absorption.  Thorough, regular cleaning of this aftercooler is essential to maximize drying performance and minimize energy consumption.

Low-quality water.  Poor water quality – or long neglected maintenance – as shown in these badly blocked in-line water filters, can allow minerals and sediments to flow into the fine channels of heat-transfer equipment, reducing chiller efficiency and ultimately leading to clogs that can cause freezing or cracking, necessitating repairs.

Moisture and corrosion.  Rust, sediments, lubricants or other impurities may also be captured in moisture traps, such as those found in the dryers used in compressed air systems (left, below).  These traps must also be emptied and cleaned regularly to ensure that they have capacity to continue protecting the equipment, then secured to prevent leaks and rust-staining (right, below).

MachineHealth™ Assessment.  Below is the MachineHealth checklist used by a Conair field technician to repair a desiccant dryer.  Performed in response to a complaint about poor dryer performance, the MachineHealth assessment indicated problems with the desiccant circuit and recommended essential repairs.

Baseline maintenance plan. A baseline maintenance plan may be based on manufacturers recommendations, unless your equipment is subject to severe conditions including excessive dust, airborne moisture, contaminated water, or high levels of ambient heat. Below are Conair factory recommendations for maintaining a D Series dryer.

Learn more about the service agreements and preventative maintenance we offer when you partner with Conair.