Cold-Related CNC Air Pressure Problems

      Below-freezing temperatures can create problems with pneumatic air supply. June 17, 2009

My router runs fine (pressure wise) 360 days out of the year, however when it gets really cold (20 degrees F), I can't seem to hold pressure in my router. Whenever the tool changes happen, the pressure drops below the E-brake line and shuts off.

I have a dedicated heater on the ceiling trying to heat the router which gets pretty hot, but I have a feeling my problem might be between my compressor and the router. Is this a common problem, and if so, is there a trick to getting my router to run better in the cold? Wrapping hoses, etc.?

Forum Responses
(CNC Forum)
From contributor D:
Water freezes at 32 degrees F. If there is any water in your air it will freeze and cause a blockage. Best thing would be to get your shop temp above freezing, plain and simple. I find it hard to believe that you would have a big expensive router in a building with no heat.

From the original questioner:
I guess in Dallas, Texas, since it only gets below freezing a few days out of the year, it wasn't cost efficient. Anyways, since I have a dryer between my compressor and router, I assume any water freezing is happening either in the compressor, the dryer, or the hoses between them. Am I safe to put heat directly on that area (it doesn't really get any as it is now)? We have small propane heaters I could potentially use.

From contributor D:
Find what the truckers use in their brake lines to keep them from freezing and dump some of that in there. Any and all heat is good below freezing. Air driers need to reach a certain pressure/temp before they are even effective. The cold weather could be causing your drier to not work properly. Heat would help. I guess I should have asked your location before commenting about shop heat. Where I'm at (central Minnesota) heat for the shop is an automatic.

From contributor M:
We are down the road from you in Houston and I thank God it is not 20 degrees down here. We keep a rule here that I heard long ago. Never run a CNC under 50 degrees. Remember metal will expand and contract. You may not see an immediate difference now, but I believe you will wear your bearings and other close tolerance ways prematurely.

We built a room just for one of the CNCs with a dedicated HVAC system for it and heavily insulated it. If the temperature is forecasted to go below 50 degrees I will have the programmable t-stat set at 50 overnight and we are good to go in the AM. Have not had the temp in the shop get down to 20 degrees, so we have not had to test the compressor.

Depending on if you own your building where you keep your CNC and the ceiling height, it would probably be beneficial for you to enclose it and use a roll up garage door to save space or make big bi-fold or sliding doors so you can get your material and/or forklift in and out. We built the room with a strong enough ceiling so we could deck the top and use it for storage. So we actually gained about 600 sq ft of space.

From contributor N:
Have you spoken with the manufacturer of the equipment? It would be my belief that the recommended operating temp is well above 20 degrees. I would think the cold would not only affect the machinery, but also the boards and quality of workmanship by employees in shop with the temp below freezing.

From contributor J:
Your air dryer probably works by freezing the water out of the air Ė itís a refrigerator/water condenser. If itís operated in a cold environment, it will over-cool and ice up, restricting the air passage and dropping pressure. This happens all the time in the great white north - very common.

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