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Running an Air Compressor in Cold Weather Months

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Freezing winter temperatures can have adverse effects on your air compressor system, its components, and accessories. This can lead you to run into some serious problems so this article will provide you with all the necessary information about how to run an air compressor in colder weather, including the additional maintenance.

Table of Contents

Running Air Compressors in Cold Weather

So what is it about cold weather that makes compressed air systems difficult to perform optimally? Most compressed air systems are designed to operate in temperature conditions above 40° Fahrenheit and in the winter months, when temperatures drop below this, the compressed air system is likely to sustain both short-term and long-term damage.

The main reason is due to the moisture or condensate generated inside the system which is liable to freezing. When it freezes, the compressed air system may become clogged at certain components, or even undergo cracking. The last thing you want is for a component in the compressed air system to become frozen and halt further use or operations.

There are several effects that a cold ambient temperature will have on your compressed air system. The most affected include:

  • Air Compressor Control Lines
  • Air Compressor Oil
  • Air Compressor Regulators
  • Air Dryers – Desiccant Air Dryers & Heat Exchangers
  • Compressed Air Filters
  • Drain Valves
  • Rotary Screw Air compressors

In freezing temperatures, refrigerated air dryers may begin to operate too efficiently, meaning the moisture being separated out by the dryer is cooled so much that it freezes within the heat exchanger leading to blockages or significant damage.

All other air compressor components and accessories are also vulnerable to damage in cold conditions because of the flowing condensation in the air moving through the system. Air compressor accessories and even receiver tanks can be suspect to air or water blockages due to the frozen condensation. In the case that enough ice is allowed to build up in the receiver tank, this will cause expansion and permanent damage to the tank, and maybe even an explosion!

The air compressor components are also more likely to corrode faster in cold weather. Moisture can build up and remain in the system for a longer period, and if this moisture doesn’t freeze which is an issue in itself, the moisture will cause components to rust.

Now, let’s take a look at each of those listed affectees in more detail!

Air Compressor Control Lines

Air compressor air lines accumulate moisture from condensate during the normal operation of an air compressor. Because of this, in freezing temperatures, they’re likely to freeze and adversely affect the compressor’s performance.

Air Compressor Oil

As ambient temperature drops the air compressor’s oil becomes thicker. When this happens, the lubrication capabilities are significantly reduced and thereafter require additional power to operate the pump effectively. Now, the motor will need to draw higher air compressor amps and adversely increase strain on the motor itself. This will reduce the lifespan of your air compressor’s motor over time.

Air Compressor Regulators

If the air compressor regulator were to freeze in the winter months, you’d likely experience pressure fluctuations that would compromise the machine’s performance to deliver your pneumatic tool’s required air pressure.

Air Dryers – Desiccant Air Dryers & Heat Exchangers

When it comes to desiccant air dryers, any air entering the inlet is likely to freeze inside the piping and cause a blockage in the airlines. This then leads to the malfunction of the tower switching valves. If the discharge air purge mufflers were to freeze then the purge airflow would either be restricted or completely stopped and so, the drying capacity of the systems dryers decreases.

Freezing moisture inside the heat exchanger is more than likely to block the system and may also lead to cracking. If the drain valve on a refrigerated air dryer becomes frozen and left open or closed you will have even more issues. This will block the condensate from draining properly or at all, and so, with the moisture not being able to escape, the dryer effectively becomes useless.

Compressed Air Filters

Cold weather damage to compressed air filters can cause restriction and the prevention of efficient airflow. Ice buildup within the air filter can cause fractures to the filter bowl and so, you will experience major pressure reduction.

Drain Valves

If water were to freeze due to low temperatures in a drain valve it can result in cracking. Especially auto drain valves, as you rely on them to drain themselves so they must be checked frequently.

Rotary Screw Air Compressors

Rotary screw air compressors are one of the most common types of air compressors. They often come equipped with some form of low ambient temperature sensor which prevents their system from starting if the ambient temperature is below 40° Fahrenheit. In the case that the compressor is already running, it will generate enough of its heat to keep it above freezing temperatures, but, this does not mean that other parts of the system are not being impacted by the cold temperatures.

Running Air Compressors in Cold Weather Maintenance Advice

Any damage caused to your compressed air system due to low ambient temperatures can lead to expensive repairs, rendering you unable to use your compressor and halting all progress on your projects. This damage can, however, be avoided by taking the necessary air compressor maintenance steps on a regular basis. This preventive maintenance includes:

  • Cold-Proofing Your Air Compressor System
  • Cold-Weather Preventive Daily Maintenance
  • Weatherproofing Your Air Compressor Room

Let’s take a look at what each one involves in more detail!

Cold-Proofing Your Air Compressor System

If the surrounding area of your compressor is difficult to keep above 40° Fahrenheit then there are some steps you can take to cold-proof the compressor itself. These include adding appropriate insulation for the pipes the system’s components to help reduce the risk of freezing. You could also fit an internal sump heater on your compressor to help keep the temperatures above the 40° Fahrenheit. Though this may be more suited to an industrial air compressor.

If your air compressor doesn’t have one already, it is advised to install a low ambient temperature sensor so that your compressor doesn’t run in cold temperatures and so, will prevent any permanent damage from occurring. You could also look at introducing trace heating around the pipes to prevent ice obstructions and help your air dryers work more efficiently.

Snowflake macro

Cold-Weather Preventive Daily Maintenance

The steps you should take to protect your air compressor and its components from cold weather on a daily basis include:

  • Checking the air compressor pipes and components far from the motor for moisture and ice buildup
  • Checking the auto drain system for obstructions and ice build up. If yours is manual, then you should drain the condensate daily
  • Checking oil levels and potentially change the oil to a lighter winter-grade to suit the colder weather
  • Checking filters for signs of icing of blockages and replace the filters when necessary

Weatherproofing Your Air Compressor Room

Another preventive step is weatherproofing the room in which your air compressor is situated by utilizing heaters or proper ventilation. It’s important to be aware that you don’t need to heat the room to the same levels human comfort requires, anything around 45° Fahrenheit will suffice and go a long way to maintaining your compressor through the winter months.

Of course, if you’re going to implement a temporary heating source you must ensure it’s installed correctly and that you don’t create any fire hazards.

Restart a Frozen Air Compressor Guide

Even with the preventive maintenance provided, it’s not guaranteed that your compressed air system won’t freeze. If it does, and you’re wondering how do you start a cold compressor, here are some steps on how to get it started:

  • Shut off all external fresh outside air sources
  • Remove or open any doors/panels of the compressor if it is enclosed
  • Add a heat source or turn up an existing one to get the ambient room temperature above 45 degrees Fahrenheit
  • Add a heat source to the bottom of the sump tank until the oil is warmed above 70 degrees Fahrenheit
  • Reset the alarm on the control panel once the compressor is at the desired room temperature. Now you can start the machine
  • Inspect all components for leaks and condensate drain valves when running


Air Compressor Won’t Start When Cold

The typical reason the air compressor will not start when cold is because of the air compressor oil. If your air compressor is an oil-lubricated model when it becomes cold, the oil will become thicker, and more viscous. Now that the oil is thicker, it will move more sluggishly.

So you now have this cold air compressor with cold, thick, and maybe frozen oil that won’t start! Your air compressor is already marginal when it comes to the power available when it is starting in warm weather. And now we have this issue that the compressor operation may now not be optimal since it’s no longer new, along with being cold.

The additional load put on the motor by this thickened oil will result in the motor not being able to turn over, you may get a fuse has blown or a breaker that let’s go, and at the least, the compressor will not start when it is cold.

A solution for this is to bring the compressor indoors a couple of hours before you want to use it. Here you can let it warm up to room temperature, and then plug it in and/or turn it on if yours has an ON/OFF compressor switch.

That should hopefully do the trick, assuming that trying to start it when it was cold hasn’t created another compressor start problem that is not related to the compressor temperature. You, therefore, may need to do one of the following:

If you’re having trouble identifying an old air compressor, visit our guide for tips!

FAQs (Frequently Asked Questions)

Do air compressors work in cold weather?

Air compressors can still operate in cold weather but you’re likely to cause either short-term or long-term damage by doing so. It is generally advised that air compressors shouldn’t be run below 40°F unless specified otherwise. You’ll risk the moisture content inside the compressor freezing and either causing parts of the system to clog, or crack.

How do I keep my air compressor from freezing?

To stop your air compressor from freezing you need to weatherproof the room in which the compressor sits, maybe by installing a heater to produce hot air and get the room temperature above 45°F. You could also cold-proof the compressed air system itself in a number of ways, including insulating the pipes by inserting a sump heater. Finally, conduct daily preventive maintenance on the system like the oil level and all the components for signs of frosting or cracking.

Can you keep an air compressor outside?

Yes, you can keep an air compressor outside but you must be careful as they’re not designed to be exposed to extreme weather conditions. Direct sunlight, snow, cold weather, and heavy rain can all provide extra strain on your compressor which will cause premature wear. If you wish to store a compressor outside you should definitely keep it under some form of weatherproof cover.

Can you leave an air compressor in the cold?

It’s certainly not advised, but if you do, you must conduct a series of checks before starting the compressor to ensure it is in working order. Even then, it is likely that the efficiency of the compressor has been adversely affected by the cold air temperatures.

Can you leave an air compressor outside in winter?

You can, but is it recommended? No! Leaving a compressor outside during winter is going to cause all sorts of problems. If you do, however, ensure that the compressor is covered, insulating and conduct regular checks to maintain it.

If you have any questions regarding running air compressors in cold weather months, please leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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