Do you drain your air compressor tank?

Originally Posted by nomas
I don't like blowing moisture into my tires when I air them up . Possible damage to the tire pressure monitors ? I don't know but that's my theory anyway .



In your area those days are probably pretty rare except for winter time.
 
My home compressor gets drained after each use. When the compressor is not in use, I keep the drain valve open.
 
I open the drain after each use. The pressure forces the moisture out so there is little if any moisture left in the tank.
 
Originally Posted by The Critic
My home compressor gets drained after each use. When the compressor is not in use, I keep the drain valve open.

This is my practice..
 
At auction I bought the used but running compressor from an out of business service station turned into a convenience store. It had a 120 gallon tank. Evidently when they change to convenience store, they never drained the compressor. It drained for over an hour, drained in the back of the truck and was still draining when I got it home. I imagine the tank was severely rusted, since the drain was very slow due to rust blocking the drain. So I cleaned up the outside, and sold it for a profit. I wonder if the tank is leaking air yet.

Rod
 
My Craftsman's compressor is leaking somewhere so it's like daily drain of air but not water......very annoying.
 
Originally Posted by ragtoplvr
At auction I bought the used but running compressor from an out of business service station turned into a convenience store. It had a 120 gallon tank. Evidently when they change to convenience store, they never drained the compressor. It drained for over an hour, drained in the back of the truck and was still draining when I got it home. I imagine the tank was severely rusted, since the drain was very slow due to rust blocking the drain. So I cleaned up the outside, and sold it for a profit. I wonder if the tank is leaking air yet.

Rod



Supposedly they peel back like a sardine can and explode when they rust through. I don't know if that's only if you continue to use a leaky tank or what.
 
Originally Posted by motor_oil_madman
Originally Posted by ragtoplvr
At auction I bought the used but running compressor from an out of business service station turned into a convenience store. It had a 120 gallon tank. Evidently when they change to convenience store, they never drained the compressor. It drained for over an hour, drained in the back of the truck and was still draining when I got it home. I imagine the tank was severely rusted, since the drain was very slow due to rust blocking the drain. So I cleaned up the outside, and sold it for a profit. I wonder if the tank is leaking air yet.

Rod



Supposedly they peel back like a sardine can and explode when they rust through. I don't know if that's only if you continue to use a leaky tank or what.


This old fools tale has been refuted many times.

That defies logic and basic understanding of a compressor.

First there is a pressure regulator.

Second, a pressure relief valve.

Why would a rusty tank explode, even if both devices failed?

It would leak, like a punctured tire leaks air.
 
Last edited:
I wonder when when an air compressor tank should be retired? Should I just sell it at the 20 year Mark?
 
Originally Posted by user52165
Originally Posted by motor_oil_madman
Originally Posted by ragtoplvr
At auction I bought the used but running compressor from an out of business service station turned into a convenience store. It had a 120 gallon tank. Evidently when they change to convenience store, they never drained the compressor. It drained for over an hour, drained in the back of the truck and was still draining when I got it home. I imagine the tank was severely rusted, since the drain was very slow due to rust blocking the drain. So I cleaned up the outside, and sold it for a profit. I wonder if the tank is leaking air yet.

Rod



Supposedly they peel back like a sardine can and explode when they rust through. I don't know if that's only if you continue to use a leaky tank or what.


This old fools tale has been refuted many times.

That defies logic and basic understanding of a compressor.

First there is a pressure regulator.

Second, a pressure relief valve.

Why would a rusty tank explode, even if both devices failed?

It would leak, like a punctured tire leaks air.



The regulator and relief valve have nothing to do with a tank failing at a normal operating pressure due to rust. They do explode and kill people.
 
I don't have a home compressor, but do trade off maintenance of the one at work with a few other people.

Ours supplies air all over the building, and some high dollar and sensitive stuff depends on it. The single biggest use is the NMR spectrometers, but there are a few FT-IRs that get a constant purge of air and I also sporadically run both an atomic absorbance spectrophotometer and a GC-FID on house air. We use an in-line refrigerated dryer between the compressor and the tank, have water and hydrocarbon scrubbers centralized(away from the compressor room). My FT-IRs also have an indicating mol sieve trap feeding into them(and have silica gel dessicant packs on the bench) and I run an activated carbon scrubber on the GC. The GC final scrubber is more for my own sanity, as residual hydrocarbons(both from oil and from methane in the air) raise the baseline and lower sensitivity, while water can wreck the salt optics in FT-IR in pretty short order(that's several thousand dollars to fix in a best case scenario).

In any case, the main tank is actually original to the building from the early 1980s, but gets periodically tested and is still structurally sound because it is meticulously maintained. The compressor is only a few years old. Someone(rotating schedule) drains the water from the tank at least once a week, although the refrigerated dryer means we barely get more than a quick spray when it's opened. Last summer, the dryer was down for a few weeks, and the amount of water was brutal-we vented and completely drained the tank weekly then.

I worked in another lab building years ago that had air plumbed to the benchtops, but nothing delicate running on it. I also never could get physical plant to drain it or at least unlock the compressor room so I could do it myself. I seriously doubt that compressor had been touched in 20 years or better at the time, although it still churned away. Opening a bench tap(which was 3 floors up from the compressor) could get a 20 ft. long spray of brown aerosolized water. More than once, I was able to get a single bench tap working well enough for a week or two-my usual procedure was to actually take a long(~30 ft) piece of Tygon tubing, hook one end up to the tap, and run the other end out the window. I'd then turn it on and just let it blast for a half hour or so. Don't let your compressor get like that! I was afraid the tank was going to go boom one day...
 
Originally Posted by motor_oil_madman
I wonder when when an air compressor tank should be retired? Should I just sell it at the 20 year Mark?


Mine's 37 years old, A good thick pressure vessel can last indefinitely if water doesn't sit in them for years at a time.

Those little Cracker Jack Toy pressure vessels shown in those photos were probably never ASME certified/registered to begin with.

Your tank should have a data plate or sticker if you're curious to know the specifications of the Pressure Vessel, I haven't personally seen or know of an actual explosion involving a industrial/commercial air compressor vessel......But I've seen plenty of them leak from pin holes caused by rust.
 
Last edited:
For the home hobby mechanics that might use the air compressor 1-2x per month, do you guys leave it pressurized all the time? Or just turn it on before a job, then drain it fully?
 
I once worked in a small Lathe / Milling shop. Had a big air compressor, bath tube size tank. Placed in the attic of the building, above the shop.
This was running for years... the boss dont belived in Maintanance.
One day, Water cames out of the air guns. No Kidding.

Turns out, the whole Compressor Tank was FULL with water! The funny thing was to empty it. Hauling a big floor jack and a big pan the steep stairs up under the attic, then jack the compressor up so you can slide the pan under it, let water flow in the pan, when full, pull the pan out, empty the pan with buckets, going downstairs and empty the buckets, repeat many times.

Great fun.
grin.gif
 
My 20gal compressor is over 30 years old now. I drain it every couple of years whether it needs it or not. Not much water every comes out of it, pretty dry here in Colorado.
 
This thread reminded me to drain mine. Nothing.

I do have an auto draining pressure regulator/ filter that seems to collect some water though.
 
I put a piece of galvanized pipe on the bottom of mine with a valve on the end to give easier access. Another benefit is water will collect in the pipe vs the tank. Water always comes out clear.
 
Originally Posted by hatt
I put a piece of galvanized pipe on the bottom of mine with a valve on the end to give easier access. Another benefit is water will collect in the pipe vs the tank. Water always comes out clear.

That is exactly what I did when I bought my compressor 22 years ago.
 
I drain mine almost every time use the compresser. The quincy is an awesome unit.
 
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