Restarting Your Compressors After COVID-19

Thursday, June 4, 2020

Many businesses have been shut down during the COVID-19 pandemic.

Compressor maintenance

Many businesses have been shut down during the COVID-19 pandemic.  As lockdown restrictions begin to ease, thoughts are turning to rebuilding demand, bringing furloughed staff safely back into the workplace and restarting production systems as efficiently as possible.


According to BCAS (the British Compressed Air Society), around 70% of all UK companies use compressed air.  That represents a significant number of compressors of all types.  Many of these will have been shut down, or at best used intermittently during the COVID-19 shutdown.


Shutting down a compressor for a prolonged period should always be carried out following the manufacturer’s instructions. These normally include manually stopping the compressor, rather than through a centralised controller, to prevent the machine from trying to compensate for air leaks in system pipework; isolating water cooling systems; and leaving electrical power switched on for variable speed drives to ensure capacitors remain fully charged.


If you’ve had to shut your compressors down during COVID-19 then hopefully you followed the correct procedures. If so, then this will reduce potential problems during restarting.

There are, however, a number of key measures that should still be considered to ensure that your compressors are restarted safely and without the risk of costly damage.


The correct way to restart compressors


Before doing any work on a compressed air system make sure that you are wearing the correct PPE and have isolated the machine from its power source.

The first step is to carry out a visual inspection. Check that nothing has been damaged during shutdown, that all connections are intact and that there are no oil or water leaks. The condition of oil should be inspected for discolouration or particulate matter; if in doubt, arrange for the oil to be checked by your service provider and, if necessary, changed to avoid the risk of damage to lubricated parts within the compressor.


Additionally, make sure that all intakes and filters are free of obstructions – strange as it may sound, it’s not uncommon for animals or birds to try and build nests on or inside compressors!


If everything is as it should be then it may be necessary to prime the air-end.  This is essential if the machine has been shut down for eight weeks or more and requires a small amount of oil to be added to the suction controller prior to start-up.  It is important to use the same grade and brand of oil as that already in the machine.


If your compressor is belt-driven then ensure that all belts are tightened to the correct tension.  Similarly, if a separate controller is installed then this must be correctly powered-up.  It may also be necessary to carry out an insulation test on the motor, in case condensation during shutdown has caused moisture to collect inside the casing.


At this stage, you should be ready to restart the compressor.  Our recommendation is to start the machine with the outlet valve to the receiver closed, wait for the compressor to reach operating pressure and then slowly open the valve to equalise the pressure.


If you have any concerns about restarting your compressors then please contact our UK technical support team on 0800 318104, or email us at