Preparing Compressed Air Systems for Winter: Part 1

Cold weather brings with it a particular set of challenges for compressed air systems and a number of problems can occur when temperatures drop below 5˚C (41˚F).

Here are some common problem areas to look out for:

Air Compressor Oil:

If the temperatures drop below 5°C (41°F), the viscosity of the compressor oil can increase, impeding the free movement of internal components and resulting in higher electrical loads or even motor overheating issues.

Localised Freezing:

Localised Freezing is what we call areas specifically vulnerable to icing or freezing and this can happen at several points in your compressed air system when temperatures drop below 1°C (34°F). At 0°C (32°F) water will freeze and any condensate in the system will begin to turn to ice. If moisture is not removed at the right point in the system accumulated condensate can cause a number of issues.

Compressed Air Filters and Condensate Traps:

Compressed air filters and condensate traps all have drains to purge condensate water from the system. Effluent drain points can be particularly problematic because they are further away from the main air stream and are heavily loaded with water. This means freezing can often occur more rapidly in these areas

Refrigerated Air Dryers:

Typically, refrigerated dryers will only lower the pressure dew point to 4˚C (39 ˚F), meaning that if the compressed air temperature drops below this temperature condensation will still occur. In cold conditions, refrigerated compressed air dryers can become too cold and freeze internally causing severe pressure drop or, in the worst cases, stop air flow completely.

Desiccant Air Dryers:

With desiccant compressed air dryers, localised freezing problems can also happen at any point where air is exhausted.

Valve Icing:

Pneumatic control valves can operate slowly when the air is cold. Lubricants can become more viscous and small orifices can quickly become blocked with ice.

External Compressed Air Lines:

Even if the main compressed air system is indoors pipes may exit the heated space for some distance before re-entering another heated space. If condensate exists in the pipework as it exits a heated space it may freeze when exposed to a colder ambient temperature. This is particularly true if the pipework has low points where liquid may be allowed to collect.

Find out how to prevent and resolve localised freezing problems, and how to prepare your compressed air systems for winter, in Preparing Compressed Air Systems for Winter: Part 2