Air lines freeze up

by Tony Greer
(Cresco, IA)

i work in an automated feedmill and the air compressor that opens and closes my scale gates is located in a warehouse about 60 feet away from my mixing room. when the weather gets cold i have a problem with the vapor in the lines freezing and not allowing the celinoids to function properly which in turn won't allow the gates to open/close is there a way to use an air tool oiler or something to bleed airline antifreeze into the lines periodically

Bill says...

Hello Tony:

I suppose you could put an air line lubricator in the line to add anti-freeze, but I don't recommend it.

I don't know what the anti-freeze would do to seals and so on, and then you would have anti-freeze fogging out the valve's exhaust port, too.

I think what you need to do is install a desiccant dryer to remove all water vapor until the air has a DEW point below the coldest point through which the compressed air has to travel. Pretty much bone dry. Then there is no vapor to condense and freeze.



Comments for Air lines freeze up

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Jul 27, 2011
Another Option

Try They have a variety of solutions for any size of compressed air systems that are experiencing freeze-up.


Very interesting, and worthwhile looking into.


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Portable compressor freezing lines up

by noel brady
(cavan Ireland Europe)

We are having problems with our compressed air frezzing in our tools for pumping insulation, we have a 106cfm at 7 bar compressor running in a truck body, the air temp is 3 degrees and the hose lenght is 40m.At the end is a PCL coupling which is freezing.We have two inline filters which remove the moisture aparently.Is there something else we can do, warm the air? Add antifreeze in the oiler?The equipement is using 2 x 40 cfm. We have to keep dipping the tools into warm water to unfreeze them.

Bill says...

Noel, the lines are freezing as you are pumping hot, moist, water vapour-laden compressed air into lines that are running through cold temps.

The water vapour in the lines is condensing, and freezing. You need to strip the water vapour out of the air, not just the free water, from the compressed air stream before it gets to the cold lines.

How much money do you want to spend on desiccant air dryers?

Good luck.


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Jan 02, 2010
by: Anonymous

Hi Bill,

We put on 2 large expensive filters costing 289 euro each, they brought it to 0.05 and 0.01 micron which we expected to be good enough,It seems the hand tools are going to have to be coated to prevent them freezing or add your filter if I can find one,not much luck on the net,I am getting some in teflon coated but the valve will probably still freeze up,We pump insulation through the hand tools which works in a venturi effect with the compressed air creating the venturi effect.


Your filters are designed to remove fine debris and free water, not water vapour.

In order to remove water vapour, so there is no condensation of water in sub-zero lines, is to use a desiccant dryer to remove all water vapor below the DEW point of the lines through which the compressed air will travel.

Try using desiccant dryer in a search engine to find a source.


Dec 30, 2009
Desiccant air dryers
by: noel brady

Hi Bill,

We have two filters on the Air line before it goes into the 40m coils,these take out a lot of the moisture as you cannot get any smaller filters.We are fitting lubricators on one and putting in antifreeze in instead of oil to see if it helps.We have 200 euro to spend approx on each truck.How much are the dryers you talk about costing?
Noel, you don't say what filters you have, but I'm guessing they are general purpose type units with perhaps a 40 micron element followed by one with a 5 micron element? These filters will take our free water, but they don't take out water vapour. That's what you need. The air exiting the warm space to the cold space must have a DEW point below the ambient outside temperature, or condensation will develop, and then freeze.

I don't sell compressed air components from this website, though I'm sure some of my advertisers do. Do a web search for desiccant dryers, find a local source, and ask them to recommend what you need.



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Plumbing compressed air outside.

by Dave

I need to pipe compressed air from one building, outside and into another building.

Temperatures can get down to minus 35 below zero in the winter months here.

Would placing an insulated pipe inside of an insulated box with air from the two buildings allowed to circulate in the box between the buildings be enough to not give me any problems with moisture?

The distance between the two buildings is 20 ft.

Thank you.


Bill answers...

Hi Dave:

The problem of water in your pipe between buildings is that it will freeze in the winter time, and, depending on how much water your compressor generates, there's a real possibility of ice closing the inside of the pipe entirely.

Picture a cold beer on the railing of your deck. It's mighty hot outside, and it doesn't take long before beads of water form and start dripping down the outside of the bottle as water vapour in the air condenses on the cold surface of the beer bottle.

The cold beer inside your bottle is equivalent to the cold air that will be on the outside of your compressed air pipe running between the buildings.

The compressed air inside your pipe is warmer than the outside of the pipe passing through minus degree temperatures, and so condensation takes place inside your compressed air pipe as does on the outside of your ice cold beer bottle in the summer time.

If you have moisture in your compressed air (whether free water or water vapour)and that compressed air gets exposed to a surface that's colder than the air itself, then condensation takes place.

In order for compressed air to flow in a pipe outside in sub-zero temps, and not have water condensing out inside the pipe, either the compressed air has to be colder than the temperature outside the pipe or the compressed air has to be dried to a dew point below the temperature of the inside surface of the pipe through which it flows.

With the steps you are taking to insulate the pipe, you must make certain that the pipe temperature stays above the temperature of the compressed air passing through it, and, for safety's sake, you want to have that compressed air passed through an air-dryer before it exits the building.

Please follow this link for information on air dryers.

Hope this helps.



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What hose material is suitable for running underground for a compressed air system?

by P. Stam

I need to run air to multiple stations via underground. What can I use?


Bill says...

P. Stam, hi. I don't know!

I would think that polyethylene tube would be suitable, as public works uses P.E. pipe to plumb water underground, suggesting to me that it doesn't deteriorate.

What size of line are you considering? What is the line feeding? If you need larger than 1/2", you may want to look at Rubber hose, or a rubber vinyl compound air hose.

To be safe, once you know the size required, and you've decided that a particular material might suit, it were me, I'd contact that manufacturer to make sure.

Sorry I couldn't be more help.



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