Compressor Service - Frequently Asked Questions

How often should a compressor be serviced?
The recurring maintenance intervals depend on the actual operating hours and time. This means that a compressor that does not reach its operating hours within 6 or 12 months or until the next recurring maintenance, it still needs a service as various wearing parts and filters are subject to an ageing process. With special consideration of the operational safety and the guarantee of a trouble-free operation, it is recommended to observe the specified maintenance intervals depending on the type of plant. Minimum interval 1 x per year.

How often must I change my compressed air filter (oil filter, air filter, fine separator filter, compressed air mains filter)?
Depending on the filter element and function, the filter elements should be changed every 6 or at least every 12 months.

Why should I replace my filter element regularly?
In order to ensure a continuous supply of high-quality compressed air and to reduce energy costs, filter elements must be replaced regularly.

How often must the oil be changed?
The oil change is usually carried out in connection with recurring maintenance. Mineral compressor oil should be changed every 4000 operating hours. Synthetic compressor oils can usually be operated twice as long. However, depending on the installation and suction conditions, the oil change intervals may vary. In case of doubt it is recommended to have the condition tested in the laboratory by means of an oil analysis (oil check).

What kind of oil should I use?
In principle, a compressor oil approved by the plant manufacturer must be used. The compressor oil is of the greatest importance in the compressor (for oil-lubricated screw compressors). The oil must cool, compress and lubricate. However, it also needs the property to be separable again afterwards. Depending on the application of the system, mineral oils can also be used as synthetic or food oils. 

When do I have to replace the compressor stage?
The compressor stage (oil-lubricated screw compressor) is subject to bearing wear due to its design. The bearing manufacturers specify a running performance of approx. 35,000 operating hours for their bearings. Therefore we recommend the preventive exchange of bearings after reaching the operating hours. When concluding a warranty agreement (Assure) the preventive exchange is regulated. 

When do I have to carry out a pressure vessel test?
The recurrent pressure vessel inspection is regulated by the Ordinance on Industrial Safety and Health (BetrSichV). This specifies: Perform a visual inspection every 5 years and a pressure test every 10 years.

The test can be performed by a competent person if the pressure volume product is less than 1000L (maximum permissible pressure of the tank x tank volume < 1000L): (CompAir service engineer). Over >1000L, the test is carried out by an expert from an approved inspection body (ZÜS) such as TÜV or DEKRA.

Do I have to take a DGUV3 test at the plants and if so, when?
DGUV 3 is an accident prevention regulation of the German Social Accident Insurance (DGUV). ... The DGUV 3 in particular deals in detail with electrical systems and equipment used commercially. The recurrent inspection of compressors is based on the risk assessment for air compressors. As a rule, the inspection takes place every 4 years. The inspection can be carried out by the service technician in connection with maintenance.

Can I conclude a special service agreement for my compressor?
Every compressed air station has its own special features and special requirements. You can obtain a service agreement for each of these requirements and determine the scope of the agreement yourself. In this way, together we ensure that operating costs and operational reliability are guaranteed.

Is there a monitoring system for the compressors?
For all compressors we offer an iConn compressor service. This system monitors the operating conditions of the compressors and thus enables 24/7 monitoring of the plants.

Can I retrofit a heat recovery system on my old compressor?
In principle, a heat recovery system can be retrofitted. However, the design for this must be agreed.

How long is the lifetime of a compressor and how can it be extended?
The service life of a compressor is primarily based on the operating hours and not necessarily on the year of manufacture. Therefore, it is not necessarily possible to quantify a service life. Due to technical progress and subsidy programmes, it should rather be examined whether an economic and ecological added value can be created by replacing an older system.

This can also be achieved by modifying existing systems, e.g. by replacing energy-efficient electric motors or retrofitting heat recovery systems. 

Why does the compressor tank heat up?
During the compression process / compression energy is released which heats the compressed air and the compressor oil. 

How much compressed air can flow through a pipe?
The amount of compressed air that can flow through a pipe depends on a number of factors, including pipe diameter, material and conditions. For more information, check the specifications on or the pipe manufacturer's specifications.

Can an air compressor explode?
You should always bear in mind that compressed air can be dangerous and should therefore be used with appropriate caution. Even high quality compressed air equipment can have defects if used, handled or maintained incorrectly. Since the compressed air is under high pressure, there is a risk of sudden decompression in the event of a defect.

Can the container of an air compressor be welded?
In the event that the vessel of an air compressor needs to be welded, the welding operation must be performed by an ASME certified welder, as all pressure vessels supplied by Ingersoll Rand are certified. Therefore, all welding work on these vessels must also be carried out by ASME certified welders.

Does the operation of an air compressor produce carbon monoxide?
Air compressors compress the ambient air. Electrically powered air compressors do not produce carbon monoxide when operating, but they do suck in carbon monoxide and compress it if it is present in the ambient air. Always check the applicable regulations if you have concerns about carbon monoxide.

Does a compressor filled with compressed air weigh more?
If the air reservoir contains compressed air, it weighs more than when empty. You should never move or work on compressed air equipment under pressure or connected to the power supply.

Does it make sense to switch off the refrigeration dryer at the end of production to save energy?
Ecologically, it is of course always sensible to switch off unnecessary energy consumers.  However, with a refrigeration dryer, it should always be remembered that the dryer capacity is not immediately available after the dryer has been switched on. The refrigerant dryer needs a pre-run to cool down its system. This time varies from dryer to dryer, so as a precaution the dryer should be switched on half an hour before the compressor starts.

If it cannot be ensured that the dryer is started in time, the dryer should remain switched on permanently, because the costs and energy required to remove the condensate from the piping system far exceed the possible savings by switching off the refrigeration dryer.