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Air Compressors and cold weather

Air Compressors and Cold Weather

Air Compressors hate cold weather

Air Compressors are designed to operate in ‘normal’ European ambient temperatures between about 5’C and 35’C. Outside these temperatures they start to have problems with either overheating or freezing. It should be remembered that the ambient temperature should be the temperature around the compressor itself, which is not necessarily the outside air temperature. The compressor ambient temperature will vary from the outside air temperature depending on whether it is in a heated compressor room, in an unheated, ventilated compressor room or outside under a rain cover.

It needs to be stressed that air compressors need to be situated in a very well ventilated place, so even if the room is heated there will still need to be plenty of ventilation for the compressor to work properly.


Problems start when the temperature falls below 5’C

As the ambient temperature starts to fall below about 5’C problems can start to occur. The low temperatures cause several issues within the compressed air system. These are primarily related to the fluids within the compressor itself and to the condensate created in the compression process. Note: when the compressor is running and is up to its normal working temperature the ambient air temperature is not too much of a problem, except if the actual compressed air is routed to a low temperature area and has not been adequately dried.


Air Compressors and cold weather – What can go wrong?

Air Compressor Oil

The air compressor coolant or oil is affected by low temperatures. Oil tends to get thicker when it is cold, if the oil is aged or of poor quality the oil may become too viscous. Either way the thicker oil may prevent the compressor from turning easily enough. This may lead to the electrical system tripping since the electrical demand is too high.

If the compressor is not serviced properly it is possible that the oil will contain a high level of water. This is not a huge problem at normal ambient temperatures but if the temperature falls too far this water can freeze in the oil, causing issues for the compressor at start up or causing damage to the compressor internals.


Air Compressor Condensate

Condensate is probably the cause of the biggest cause of problems for air compressors and cold weather. Condensate is formed when air is compressed and then cooled. Condensate is a mix of water (99%) and oil (1%).

Condensate tends to collect at low points within the compressed air system. These include, the compressor, separators, receivers, filters and dryers as well as in low points in the compressed air pipework. If temperatures fall low enough this condensate will freeze, blocking pipes or voids within the compressor, dryers, filters and pipework.

If there is frozen condensate in the compressor this can cause damage to the compressor, if it is in the filters or dryers again this can cause damage. If there if frozen condensate in the pipework this can get blown to the downstream equipment, again causing damage to the downstream equipment.


Air Compressor Dryers and Filters

Strangely the best protection devices for Air Compressors and cold weather are the dryers and filters built into your compressed air system. This is because this equipment removes water from the compressed air and this prevents water from freezing in the downstream pipework and equipment. So keeping your dryers and filters working effectively is important to protect the rest of your compressed air system.

Refrigerated dryers only work effectively at ambient temperatures above 5’C. So if your dryer is in an unheated compressor room this could be damaging the rest of your compressed air system. Installation of cabinet heating could help protect your dryer and the rest of your compressed air system.


5 tips to protect your Air Compressor in Cold weather

1/ Regularly drain the condensate from your compressor system

You should be doing this regularly as part of your normal daily compressor checks. But in cold weather the condensate can freeze causing blockages or damage within the compressor and compressed air pipework system. As an alternative look at fitting an auto drain system to manage condensate automatically.


2/ Fit cabinet heating inside your compressor cabinet

A simple low power heater fitted inside you compressor cabinet or compressor room will keep the compressor above 5’C and will ensure the compressor will operate correctly even after a long cold weekend.


3/ Use trace heating with appropriate lagging on external pipework

Trace heating and lagging on outside pipe runs will stop any condensate from freezing within the pipes. This will prevent problems of ice being blown into downstream plant. Alternatively look at rerouting pipework inside buildings to keep the pipework above outside temperatures


4/ Make sure your compressor has been serviced regularly

If a compressor is not being serviced regularly a number of issues can arise including a build-up of water in the lubricating oil within the compressor itself. If this water freezes this can cause significant damage to the compressor itself. Also cold oil will be thicker than warm oil, possibly creating overload issues when the compressor is starting up. A cabinet heater will help solve this issue too.


5/ Dont forget your dryers and filters

Strangely your filters and dryers are one of the most important tools to protect your system from cold weather. This makes sense when you consider they remove water from the compressed air so preventing water from freezing downstream in your pipes and other equipment. Refrigerated dryers only work effectively in ambient temperatures down to 5’C. If your refrigerated dryer is in an unheated compressor room the dryer could fail to operate correctly.


The critical issue is to keep the temperature of the compressor above 5’C. This can be achieved by fitting heaters to the compressor itself, or by heating the compressor house. It is also important to heat the filters and dryers. Finally, it is really important to heat the compressed air pipework particularly if it runs outside the building. This is easily done with low power trace heating and suitable lagging.


Click here to take a look at our advice on Air Compressors and hot weather