Air Compressor Maintenance Guide
Follow this air compressor maintenance guide for optimal performance year-round.
It goes without saying that proper maintenance is the key to getting the most out of your power equipment. Developing (and sticking to) a maintenance routine can save you time and money in the long run. We’ve developed this handy air compressor maintenance guide to help you along the way. Keep in mind that proper safety equipment should always be worn while servicing your air compressor. Do not start, operate or service your machine until you read and fully understand the owner’s manual.
Some of these recommendations are pretty straightforward, while others require instructions and/or specifications. Click each recommendation for additional information.
Check Oil Level
Prior to daily operation, make a habit of checking the oil level of the compressor pump and engine (if compressor is gas powered). Every direct-drive hand-carry air compressor has a dipstick to help check and maintain the proper oil level. The dipstick also functions as a crankcase vent. Never operate a direct-drive unit without the factory-supplied dipstick. Our belt-driven air compressors are equipped with a sight gauge to make the daily task of checking the oil level easier. Always maintain the oil level to read 2/3 full on the sight gauge.
Drain Moisture From Tank(s)
One or more drain valves are installed to allow moisture to be drained on a daily basis from the compressor storage tank(s). Open drains carefully and slowly to prevent scale, rust, or debris from becoming expelled at a high rate of speed.
Inspect Air Filter(s)
When checking filters, make sure the filter housing is structurally sound and the element is intact and free of dust and debris. If you need to replace the filter, you can obtain the part number from the schematic in your owner’s manual.
Check for Unusual Noise or Vibration
While the air compressor is running, listen for any rattling or knocking sounds. It is best to perform this step after checking the belt tension, bolts and condition of vibration pads.
Inspect Belt Guard
Ensure that belt guard cover is firmly in place and all screws are tight. Check for cracks or compromised mounting holes.
Check for Air or Oil Leaks
To check for air leaks, isolate the compressor by removing any air hoses and allowing it to fill up to top pressure. When the compressor shuts off or idles down, observe the tank pressure gauge. Keep in mind that pressure will drop slightly as the internal air temperature decreases. If the needle drops continuously, a leak is present somewhere in the system. If you can’t locate by sound, coat all fittings in a soap and water solution and watch for bubbling.
To check for oil leaks, watch for pooling oil around the base of the pump and engine (if applicable). Also, if you find yourself having to refill the crankcase frequently, the compressor may be bypassing an excessive amount of oil. In any case, take the compressor to an authorized ROLAIR® service center to diagnose and repair the issue.
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Clean Exterior of Air Compressor
Allow the air compressor to cool to room temperature before attempting to clean. Disconnect electric models from the power source. Wipe down exterior surfaces with a damp cloth. Dry thoroughly prior to operation.
Check Condition of Vibration Pads
Ensure all vibration pads are in place and air compressor sits in a level position. If vibration pads are worn or missing, refer to schematic in owner’s manual for replacement part numbers.
Tighten/Retorque Bolts
Ensure all bolts are tight. With the air compressor at room temperature, re-torque pump bolts according to the specs in the following table:
Torque Chart (inch/lb)
| Direct Drive | K17 | K18 | K24 | K28 | K30 | |
|---|---|---|---|---|---|---|
| Head Bolts | 96 | 243 | 243 | 243 | 347 | 347 |
| Cylinder Bolts | 12 | 182 | 182 | 182 | 330 | 330 |
| Bearing Carrier Bolts | N/A | 130 | 130 | 130 | 130 | 130 |
| Connecting Rod Bolts | N/A | 121.5 | 121.5 | 121.5 | 121.5 | 121.5 |
| Flywheel Nut (left-hand thread) | N/A | 382 | 382 | 382 | 477 | 477 |
Check Belt Tension
Use the diagram below to determine how much deflection is acceptable. If you determine that the belt is loose, obtain a replacement belt or make adjustments as needed. To adjust belt tension, follow these steps:
Electric
Note: Should only be performed by ROLAIR® factory authorized personnel.
- Roll the belt off of the pulley and flywheel.
- Loosen bolts that hold motor to saddle.
- Increase (slightly) the distance between the pump and motor.
- Ensure that pulley and flywheel are properly aligned.
- Tighten bolts that hold motor to saddle.
- Roll the belt on to the pulley and flywheel.
- Check tension. If there’s still too much deflection, repeat steps 1-7 until proper tension is achieved.
Gas
Note: Should only be performed by ROLAIR® factory authorized personnel.
- Loosen locknuts for engine hold-down bolts only until washers beneath spin freely.
- Rotate 1/2″ adjusting bolt until desired tension is reached.
- Re-tighten locknuts to secure engine.
- Ensure that pulley and flywheel are properly aligned.
Check Operation of Safety Valve
Locate safety relief valve (shown below) and perform a visual inspection. Look for any signs of corrosion or physical damage. With air in the system, slowly and carefully pull the ring to actuate the valve. You should hear a loud hiss of escaping air. If you are unable to open the valve, it will likely need to be replaced.
Change Compressor Oil
Use the following chart to determine which type of oil to use.
Clean/Change Air Filter
Clean air filters using low pressure, compressed air to remove dust and debris. If the filter cannot be cleaned sufficiently or shows signs of wear, obtain a replacement using the part number in your owner’s manual.
Perform Pump Up Time Test
With the tank gauge at 0 PSI and air line(s) disconnected, close drain valve(s) and record the amount of time it takes to build tank pressure. Periodically test your air compressor against this pump-up time to determine if it is operating correctly. If the time test is considerably off, contact your local authorized ROLAIR® service center.
Check Operation of System Controls
We could get overly-complicated here and write at length about how each control component is supposed to function and how they all interact. Instead, we’re going to keep it simple and just suggest running the compressor and forcing it to cycle a few times by opening the drain valves slightly. While it’s cycling, watch the tank pressure gauge to make sure the needle is rising and falling as pressure increases and decreases. If it’s an electric model, listen for a brief hiss of air from the pressure switch when the motor shuts off. This signifies that any air caught between the check valve and pump has been evacuated, making for a smooth start-up when the motor kicks back in. The motor will start up again when the tank pressure drops to a certain level, depending on the model. If it’s a gas model, you can expect to hear the engine speed decrease when the compressor has reached its top pressure setting. You’ll also hear air being discharged from the pilot valve. When the tank pressure reaches the lower setting, the pilot valve will activate the throttle control which increases the engine RPM and starts the cycle over again.
Back to Table
Check Air Tanks for Dents/Leaks
Visually inspect tanks for dents.
To check for air leaks, isolate the compressor by removing any air hoses and allowing it to fill up to top pressure. When the compressor shuts off or idles down, observe the tank pressure gauge. Keep in mind that pressure will drop slightly as the internal air temperature decreases. If the needle drops continuously, a leak is present somewhere in the system. If you can’t locate by sound, coat all fittings in a soap and water solution and watch for bubbling.