I just bought a used 24gal Ingersoll Rand compressor. It is spotless and
looks almost new. I got it home and changed the oil and air filter, then
cranked it up. Alls well. Then I drained the air (mostly), then opened
the drain plug. I got about 2 ounces of brown water.
Any thoughts on what I should do going forward? Just keep up with proper
drainage or should I be concerned about rust inside?
Sounds as if it's been kept drained, so I wouldn't be too concerned.
One of the neat ideas I came across (here on the wreck?) was to install
a short hose with a ball valve at the end in place of the stock drain
plug to make regular draining of the tank easier. I keep telling myself
that I need to do that "one of these days - real soon now". :-)
Do replumb the drain, mine was at the bottom, (Horz comp) you had to get on
your hands and knees to drain. Got drained, *maybe* once a week. A bit of
1/4 inch copper, some compression fittings and a small ball valve. $12 and
10 min. Drained every day now.
I've had one of those HF auto drains on my stationary compressor for a
couple of years now and it seems to be doing the job quite well. Every
so often I'll exercise my lower back and open the manual valve. So
far, it's always been dry.
Only problem I've had with mine is a rupture in the cheap plastic
pressure hose which was then replaced with a more substantial nylon
Mac or Tom, I've been wanting to get one of these for years but never
got around to it. The instructions at HF say this kit will not work
with switches that have copper "unloader" tubing. I assume this is
because of the supplied fittings. Would it be possible/reasonable to
make this thing work with copper fittings? I imagine the connection on
the valve would have to work with standard NTP copper fittings.
I've just read where a guy bought this HF one and he said he can't find
a fitting to match his line, and that the HF one has very non-standard
size fittings that he can't find? My compressor has a 1/4" copper
I haven't drained my compressor in years, I'm almost afraid to open the
cock and see what's in there. I'm sure I'm not the only one:-)
Tom Veatch wrote
I'm not Mac or Tom, but I hooked up a HF automatic drain to mine using
copper tubing. It worked fine for a few months then started leaking
air (not closing completely). I dismantled it a couple of times and
cleaned it out but the last time I just took it off. I have a
galvanized extension on my drain using street El's and a quarter turn
ball valve with a long handle (possibly a gas shut off valve) and it
works fine, just not automatic.
I tried two HF automatic tank drains, both failed in a short time. Check out
Grainger, item number 4KT04. Easier to install than the HF, no signal line,
just screw it to the drain hole on the tank, senses change in tank pressure
to activate it. I put one on probably 8 years ago and has worked great.
Thanks Greg. I was on Grainger for a good while searching for that very
thing and it would not come up. I looked for everything I could think
of, air drains, automatic drains, and drain valves, and about everything
else I could think of and came up with nothing. Anyway, this looks like
what I would buy although it is a lot more money at $77 vs $10. I had
replaced the pet cock on the tank with a piece of tubing and a little
brass gas valve years ago so it's not like it's hard to drain the thing.
After draining a few pints of water off after years of neglect, I think
I'll just plan on doing it by hand a few more times. I think it will
out last me as it is.
I drained my tank often enough I thought. Stinking thing started
hissing recently. Tank was only 15 years old. I need to replace the
tank if I can find one but I rarely have the need for that compressor.
I suspect that oil type compressors tanks last longer than oil-less
compressor tanks for one oily reason. No quantitative or even
anecdotal support for that except my dad's oil compressor is more than
30 years old. That Thomas oil-less compressor of mine might be 20
I don't think it's the oil in the crank case, I think it is the tank
liner. If your tank liner is missing or compromised, then you will get
rust. Air tanks will always have water and air in them, two things
needed for rust. You need something to keep the air and water off the
metal that doesn't rust. Glass is nice.
My compressor is about 30 years old and seems good. My brothers
compressor is a good bit older than that and seems good. My neighbor
had a big 3 stage compressor he told me he used when he was young and
had an auto shop. He was over 90 years old and used it daily in his
lawn mower repair shop. He never drained the thing and whomever is
lucky enough to have that thing now I'd bet it still is humming along.
Interesting story, this old guy had a 2" pipe on his regulator that he
said was filled with an oil soaked wool cloth that acted as his filter.
He had no other filter on the line. My filter has a water separator on
it but I've never seen any water in the bowl, but I don't paint much any
more, mostly just use a few air tools now and then.
I agree with you though, my guess is any failure from rust would show up
as either pin holes, or, at the worst, a small blow out hole that would
be loud as hell for a few minutes but do little damage. Still, if I were
buying an auto drain, I'd go with the Grainger one and forget about it.
There are no tank liners in the compressors I have worked with. If
there was there would be a big note on the side to go with the price
tag. Your experience might be different. I am familiar with oil. I am
familiar with oil and water. There is no reason not to believe that an
oil type compressor is not going to leak some oil which will of course
come out with the water. Where I have lived we have days of 50-70%
humidity. Water condenses like crazy inside the tanks. That same water
comes shooting out of air hoses, spray guns, nailers, whatever the air
tool. Heck I have even seen it spray like crazy from the 25 cent pump
up your tires air compressors. You have to drain that tank if you are
using the compressor. If you have a leaky drain valve or you purposely
leave it leaking the amount of condensation inside is not that great.
Yes I have left a small leak on a drain valve on a bigger compressor
to reduce the need for the lazy staff to drain it. Even with draining
the tank you still get water shooting out as the air cools with
pressure drop. Yes the manual air dryer bowels will help a bit but if
one is serous about dry air then you have to do cooling system first.
Either the fancy air dryer that uses freon or its equivalent or water
cooled dryers. Of course if you live in dry low humidity areas then
you may not see much issues with condensation.
Of course, the lower the relative humidity the better, but to avoid
tank condensation, it has to be quite low - almost desert conditions.
Take my single stage compressor that runs a tank pressure of 135 psig
as an example. Thats a compression ratio of (135 + 15)/15 = 10 to 1.
Without getting into a discourse on partial pressures, condensation
will occur if the relative humidity is greater than the inverse of the
pressure ratio. In my particular case, with a CR of 10/1, condensation
will occur in the tank anytime the relative humidity of the intake air
is greater than 1/10 or 10%. Folks that run a higher tank pressure
will get condensation at even lower relative humidity.
Yeah, these things work with the pressure switch that turns the
compressor on and off.
Not sure what would work since they say it won't work with copper or
metal lines. That could mean the kit doesn't work with metal tubing or
it could mean the valve itself won't work with standard fittings.
Yeah, a little that's why I've been wanting to get an automatic drain
for the past 30 years. Interestingly, after posting this, I went down
and drained the tank. It had less than a quart of water in it, but the
water was clear as a could be, no rust in it. I think the tank is glass
lined to prevent rust failures but when things get old enough, or not
made perfect, bad things happen. Now that I saw the water, I'm not too
worried any longer. My guess is tanks, even with auto drains, are
always wet enough to cause rust, and the main preventive is not draining
them but having the glass lining in tact.
Not too much. It sounds like the previous owner
didn't drain for a while before selling it to you,
but if you do it every evening after use, you
should be fine.
In case you don't know, compressors squeeze water
out of air (really). This water can rust inside
the tank, but usually is not a big deal unless
it's an old compressor with a compromised tank.
Thanks, guys. I didn't think it was too bad, but wasn't sure. I have
had a little PC pancake and drain it religously. When I was the brown
water I was a little concerned.
Boy is the oil-lubed compressor quiet. The pancake would rattle my
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