Each month, track compressor operating hours, loaded and unloaded time, pressure at several locations, energy use where metering is available, air-treatment performance, leaks, and maintenance history. Record production hours alongside those readings. Without that context, a higher electric bill or longer compressor runtime doesn’t tell you much.
The goal isn’t another clipboard that nobody reads. It’s catching changes early enough to distinguish a maintenance problem from a genuine shortage of capacity. For Tennessee facilities working on compressed air system efficiency, a consistent monthly record can help answer an expensive question: do we need more equipment, or does the existing system need attention?
Build a Monthly Record You Can Actually Compare
Use one shared log, with a separate entry for each compressor and common entries for the dryer, filters, receivers, and distribution system. Name the measurement locations so different technicians aren’t recording different gauges under the same heading.
Record readings under comparable conditions:
Production: Operating shifts, production hours, active lines, and major air-consuming equipment.
System configuration: Compressors running, standby equipment, control settings, and any equipment taken offline.
Conditions: Compressor room temperature and unusual heat, humidity, or cold-weather exposure.
Changes: New machines, piping extensions, pressure adjustments, repairs, and shutdowns.
A monthly review should summarize routine observations and available controller trends—not replace daily checks or manufacturer service intervals. One quiet-morning reading won’t capture the pressure dip that happens every afternoon during overlapping machine cycles.
Track Runtime, Loading, and Energy Together
Read the counters, then calculate the monthly change
Record total operating hours and, where available, loaded hours for each compressor. Subtract the previous month’s readings to get hours accumulated during the reporting period. Keep the dates consistent.
For a load/unload machine, increasing unloaded hours deserve attention. An unloaded compressor can still consume substantial power while delivering no useful air. However, the meaning depends on its control arrangement and operating sequence. A designated trim compressor won’t behave like a fully loaded base machine.
For variable-speed equipment, review speed, power, and output trends where the controls provide them. Loaded-hour counters alone may not describe how that machine is operating. Don’t treat speed percentage as a direct airflow measurement.
Also record starts, load/unload cycles, and changes in which compressor leads the system. Frequent cycling may involve storage, control settings, or demand fluctuations. It doesn’t automatically mean the compressor is failing.
Use measured power when available
Track monthly compressor-system kilowatt-hours from installed metering. Keep the measurement boundary consistent: compressor-only energy isn’t directly comparable with a later total that includes dryers and auxiliary equipment.
If there’s no dedicated meter, runtime provides a useful warning signal, but motor nameplate horsepower isn’t an energy measurement. Electrical metering installation and testing belong with qualified personnel.
Useful comparisons include energy per production hour or per unit produced, provided the product mix is comparable. Where reliable airflow metering exists, compare energy with delivered air volume using consistent reference conditions. Don’t call lower energy use an efficiency improvement if production simply slowed down.
Measure Pressure Where Production Uses the Air
A compressor discharge gauge doesn’t tell you what a machine receives. Track pressure at the compressor discharge, downstream of air treatment, and at a representative distant or demanding point of use.
Record these readings at the same time during a known production load. Comparing discharge pressure from an idle shift with machine pressure from peak production can suggest a pressure loss that wasn’t actually measured.
Record normal and lowest observed pressure: Include the production event associated with a dip.
Track filter differential pressure: Compare readings at similar airflow and against the manufacturer’s service guidance.
Log pressure-setting changes: Include who changed the setting and why.
Note local restrictions: Small hoses, couplers, regulators, and machine filters can affect delivery even when the header pressure looks acceptable.
If maintenance keeps raising system pressure to satisfy one machine, flag that pattern. Higher pressure may conceal a distribution restriction while increasing energy demand and air consumption through leaks and some end uses.
Existing gauges should also agree reasonably when measuring the same condition. Suspect instruments need verification before their readings drive equipment decisions.
Record Dryer Performance, Condensate, and Temperature
Track dryer alarms, available inlet conditions, and pressure dew point where a suitable instrument is installed. Pressure dew point describes the temperature at which moisture would begin condensing at the measured pressure. It’s more useful than simply writing “dryer running.”
Know what the display actually measures. A refrigeration temperature display isn’t necessarily a direct pressure-dew-point reading. Compare performance with the dryer’s operating limits and the plant’s air-quality requirement, not a generic target.
Monthly records should include:
Water complaints by machine, location, shift, and weather conditions.
Observed operation of accessible condensate drains at separators, receivers, filters, and dryers.
Drains that appear blocked or discharge air continuously.
Compressor room temperature, operating temperature trends, and visible ventilation obstructions.
Dryer or filter maintenance completed and whether the original symptom returned.
Hot, humid Tennessee summers can increase incoming moisture load. Higher inlet temperatures can also affect dryer capacity. Water appearing in July doesn’t prove the dryer needs replacement; inlet conditions, drains, airflow, and equipment condition all need checking.
Outdoor condensate lines and exposed piping deserve separate attention during freezing weather.
Keep a Leak Register With Repair Verification
“Found several leaks” isn’t a useful monthly result. Give each identified leak a location or tag, record how it was detected, assign a repair owner, and note its status.
Prioritize leaks using qualified survey findings, operating hours, accessibility, and production impact. Don’t assign airflow losses from sound alone. Ultrasonic survey estimates also depend on the instrument, pressure, and measurement method.
Track air use or compressor behavior during a comparable nonproduction period. First account for legitimate continuous demands, including dryer purge where applicable. A running compressor during shutdown suggests demand worth investigating, not proof that every bit of it is leakage.
After repairs, repeat the check under similar conditions. Closing a work order confirms someone performed a repair; a follow-up check confirms whether it held.
Turn the Readings Into a Monthly Work Plan
Review trends against a known-good baseline and comparable production conditions. Set investigation thresholds using equipment limits, process requirements, and normal system behavior. There isn’t one acceptable runtime, pressure drop, or dew point for every plant.
Maintain a short action list with an owner, due date, and verification method. Include service due by calendar date or accumulated hours, recurring alarms, overdue repairs, and repeat failures.
Consider a Middle Tennessee machine shop that adds CNC equipment. Compressor runtime rises, and operators report low pressure at the far end of the building. Discharge pressure still looks normal.
If synchronized readings show stable upstream pressure but a larger downstream drop during production, investigate treatment and distribution restrictions before ordering another compressor. If pressure falls throughout the system while available compressors remain fully loaded, demand, leakage, controls, and available capacity need closer evaluation. Both situations can feel identical to the operator.
Know When the Log Calls for Professional Diagnosis
Maintenance teams can review displays, listen for unusual noise, observe accessible drains, check visible ventilation paths, and document operating conditions. These observations often give a service technician a much better starting point.
Leave electrical testing, internal compressor work, pressurized component repairs, and control changes requiring specialized knowledge to qualified personnel. Intrusive work requires proper isolation, lockout, and verification that stored pressure has been released.
Bring in a compressed air professional for unexplained energy increases, recurring trips, persistent moisture, unstable pressure, or conflicting readings. A compressed air system audit with temporary pressure, power, and airflow logging can capture events that monthly snapshots miss.
Bottom Line
A useful monthly review ends with decisions: what changed, what needs investigation, who owns the work, and how the result will be checked. Keep production context beside the equipment readings, and verify repairs before treating the problem as closed.
Contact Industrial Air Services for help reviewing your Tennessee facility’s operating trends and determining whether maintenance, controls, air treatment, piping, or additional capacity deserves attention.
Industrial Air Services is an authorized Bobcat® Industrial Air Compressors distributor serving Central to East Tennessee, including Nashville, Knoxville, and Chattanooga.
(615) 641-3100
138 Bain Drive • LaVergne, TN 37086
