Make Plans for Plant Maintenance this Winter
BY Michael Petrie
Editor’s Note: The Focus on Performance series from AsphaltPro Magazine allows OEMs and service providers to highlight professionals in the industry who have improved efficiencies and the bottom line through best practices and performance. This month’s installment from Motion Engineering, Inc., focuses on plant maintenance strategies during the off season.
When the last ton of mix goes out the gate for the paving season, it’s tempting to close shop and call it a season well done. But for the forward-thinking asphalt producer, winter isn’t downtime. It’s go-time for planning, inspecting and maintaining the critical equipment that keeps production rolling the other nine months of the year. Asphalt plants are complex systems of mechanical, electrical and combustion equipment—each with their own wear patterns, failure points and maintenance needs.
Many of the failures we see in peak season—burner malfunctions, seized valves, worn-out drag slats, failed sensors—are entirely preventable. The culprit is often deferred maintenance and a lack of thorough winter inspections.
When you fail to inspect and maintain during the off-season, you’re rolling the dice on everything from your drum bearings and flighting to your silo gates and burner systems. In most cases, early detection means a simple repair; ignored, it becomes a catastrophic failure.
“What I continue to see out in the field is that we are nearing a time when a significant number of plant operators who have extensive experience are retiring.”—Michael Petrie
Winter is the perfect storm for hidden damage as moisture intrusion causes rust and electrical issues. Also, thermal cycling can cause stress cracks and reduce the strength of welds. As with all mechanical equipment, periods of inactivity can result in seizing, corrosion or undetected mechanical failure.
At Motion Engineering, Inc., we’ve been in the guts of hundreds of plants, and we’ve seen what works, what breaks and what costs producers serious money. If you’re wondering what you should inspect this winter, here’s your prioritized guide, system by system, with insider tips on what to look for and how to address potential issues before they turn into operational nightmares.
Drum/Dryer System
I have personally seen entire drum sections separate from excessive wear and lack of proper inspection. With a new drum costing upwards of $1 million, it is critical to extend the life of your current drum by properly inspecting it and completing the necessary repairs.
Here are the key areas that you should be evaluating once production stops for the season.
- Drum shell and tire wear: Look for excessive scarring, pitting or ovality. Uneven wear on tires or trunnion surfaces often indicates misalignment. It’s also important to inspect the thickness of the drum shell looking for cracks and separation.
- Flighting: Check for broken or severely worn flights that affect aggregate veil and drying efficiency. Check for worn out hardware.
- Trunnion rollers and bearings: Look for flat spots, vibration, excessive noise and leaking seals.
- Gearboxes: Check all gearboxes for oil leaks or unusual noises that may indicate failure.
- Thrust rollers: Inspect for proper positioning and contact pressure.
What to Do:
- Realign the drum if there’s abnormal wear.
- Install replacement liners if thickness testing comes back at a level reaching anything less than ¾ of the manufacturer’s original thickness.
- Replace broken or worn flighting to maintain proper drying.
- Grease and test roller bearings. If they’re noisy or have play, replace them before failure occurs.
Burner System
As a distributor for multiple combustion manufacturers, I have witnessed the catastrophic failures and the impact they have on producers when these systems fail at the most crucial of times. Particularly when spring hits and the first batch of mix is on the schedule, the last thing you need is a burner malfunction.
Just this past spring, I had a customer that waited until their first job to fire up their burner only to realize the control system was having intermittent failure that would not allow them to run. This cost them unprecedented downtime and hundreds of thousands of dollars to try to diagnose and correct the problem. A simple test run earlier in the season could have prevented this from occurring.
Here are things to inspect on your test run.
- Combustion zone and flame shape: Look for evidence of soot, poor combustion or flame impingement.
- Blower motors and controls: Check the amperage draw, noise and contactor condition.
- Fuel lines and filters: Inspect for leaks, clogs or degradation.
- Ignition systems: Check spark plug condition, transformer performance and timing controls.
What to Do:
- Clean and calibrate the burner. A proper tune-up can significantly improve fuel efficiency and reduce emissions.
- Replace any aging or cracked fuel hoses.
- Make sure all safety components are working properly: Pressure switches, safety shut-off valves, flame supervision and limit switches.
- Schedule an inspection for the fuel filtration system.
- Make sure your burner management system is functioning properly. It’s not enough just to turn it on. You need to make a test batch and ensure your burner ramps up and down properly.
Electrical and Control Systems
Any electrical or control failure at your plant is a sure guarantee of downtime at your facility. It is critical to ensure the functionality of all the equipment prior to your first scheduled job for the season. I have witnessed countless occurrences where producers have encountered electrical issues due to corrosion or water intrusion and simple weather proofing during the downtime could have prevented those issues.
Here is what I recommend inspecting and preparing for in the off season.
- Wiring and junction boxes: Look for water intrusion, corrosion and loose connections.
- Sensors and thermocouples: Test signal consistency and placement accuracy.
- Control panels and PLCs: Update software, test relays and backup settings.
What to Do:
- Replace compromised wiring and weatherproof enclosures.
- Calibrate all critical sensors.
- Perform a full system simulation before startup season.
- Have a backup CPU with your burner control program loaded.
Baghouse & Dust Collection
Lack of proper maintenance on dust collection systems can lead to decreased efficiency, increased operating costs as well as safety hazards for your employees. The last thing you need is for a fire to start because of lack of inspecting your baghouse bags. Clogged or damaged filters are a primary cause of environmental issues and higher energy costs.
Here is what I recommend inspecting once your team winds down production for the season.
- Filter bags: Check for holes, abrasion or oil contamination.
- Dampers and ductwork: Ensure smooth operation and check for buildup or corrosion.
- Pulse valves: Listen for consistent operation and monitor differential pressure.
What to Do:
- Replace damaged or blinded bags. Dust carryover leads to environmental issues and reduced efficiency.
- Clean ducting and realign dampers.
- Replace worn diaphragm valves for consistent pulse cleaning.
Drag Conveyor & Silo System
One of the primary areas of expertise for Motion Engineering, Inc., is the installation of silo liners. Whether they are ceramic or steel liners, proper installation of these liners will extend the life of the equipment for many years. Also, there are safety concerns if structural integrity is not sound. I’ve seen the silo tub wall settle or “beer can” on numerous plants over the years due to neglect.
I recommend inspecting these critical areas on the Drag Conveyor/Silo System.
- Slat chains and sprockets: Check for elongation, cracked links and worn teeth.
- Floor liners and troughs: Inspect for excessive wear, warping or holes.
- Discharge gates and cylinders: Look for leaks, delayed action or bent rods.
- Batcher Gates: Make sure batcher gates are operating properly. A batcher stuck open can allow a hole to wear right through the tub wall.
- Silo Thickness: Check the thickness of the cone and tub wall to ensure structural integrity.
What to Do:
- Measure chain stretch and replace if beyond spec (usually 2–3% elongation).
- Weld or replace worn liners—holes become heat loss zones and safety risks.
- Rebuild or replace gate actuators that fail under load.
- Use a thickness tester to properly map the cone and up the tub walls to ensure structural integrity as well as identify if liners are needed.
- Properly install ceramic or steel liners on any silo cones/tub walls that have a thickness of < ¾ of the original manufacturer’s thickness.
Asphalt Tank & Pump Systems
When it comes to annual maintenance, it’s important not to overlook your tank farm system. Just this year at three different asphalt plants, our service team removed and replaced liquid asphalt cement (AC) pipes due to restricted flow. After inspection, we identified that the pipes were clogged due to buildup that had been overlooked. This caused supply and return issues as well as offload issues.
Here are a few key areas to be focused on when it comes to inspection and repair for your tank farm system.
- Circulating pumps: Check for seal leaks, bearing play and pump performance.
- Heaters and lines: Inspect lines for coking and buildup. The most vulnerable lines are the AC lines that oil sits in for long periods of time. Make sure you understand what the max flow of your pump is. When you know that, you will know when your lines are starting to clog.
- Valves: Ensure valves are operating correctly and identify any valve stem leaks or seal leaks.
What to Do:
- Rebuild pumps if bearings or seals are suspect.
- Flush lines and test heater operation at full temperature. Repair and replace any pipes where flow is restricted.
- Repair and replace any valve leaks.
- Insulate exposed lines to prevent cold-weather failures.
What I continue to see out in the field is that we are nearing a time when a significant number of plant operators who have extensive experience are retiring. Less experienced plant operators are taking over those roles and they lack the proper knowledge of what to look for. This is causing problems for producers. Your team might be capable, but winter inspections are the time for precision, not assumptions. Hiring experienced maintenance professionals to assist ensures your plant is not only inspected thoroughly, but also that small issues are corrected before they snowball.
Michael Petrie is the president of Motion Engineering, Inc.