Replacing compressor Drain

[Ken Krawford]

The drain valve on my PC 6 gallon compressor needs replacement and I've never liked the one that came with it. Lowes sells a 1/4 turn ball valve with a 1/4" stem. I'm a bit reluctant to start horsing on the old one because I can't see any threads protruding outside the tank. Is this stem welded or is the paint obscuring any threads?

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[John K Jordan]

The drain valve on my PC 6 gallon compressor needs replacement and I've never liked the one that came with it. Lowes sells a 1/4 turn ball valve with a 1/4" stem. I'm a bit reluctant to start horsing on the old one because I can't see any threads protruding outside the tank. Is this stem welded or is the paint obscuring any threads?

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By stem do you mean the hex nut? I don't know about yours but at least one of my compressors has a welded boss threaded for an fitting with visible threads and with a hex head, intended I think only to reduce the opening to fit a standard brass tank drain valve. You might use a wire brush on a drill to remove the paint and have a better look. But I'm not sure why the fitting would need to be replaced unless it was badly corroded (then I might be concerned about the rest of the tank.)

One thing that helps is to put the valve on the end of a piece of pipe that sticks out a bit from the bottom of the tank.

[Jim Becker]

Most compressors have 1/4" NPT threading for the drain so it's easy to replace with simple 1/4" NPT fittings and a ball valve for easy draining. The OEM drains are a pain in the backside right from the start in that respect and are also not generally "conveniently located".

[Kerry Wright]

I replaced mine last summer with a street elbow (1/4" NPT), a 4" nipple and a ball valve. Much easier to reach to drain now!

[Ken Krawford]

Problem solved. I put a wrench on it and a couple of whacks with a mallet separated the threaded portion. The pain was concealing the junction between the 2 pieces.
Thanks for the responses.

[Brice Rogers]

I have a multi-turn drain valve. I set it at the "almost closed" point about 20 years ago. It takes perhaps 3 days to 5 days to drain down the tank. My rationale for doing this is that it automatically empties the water from the bottom of the tank. When I'm out of town, I try to remember to turn off the tank so that it doesn't cycle unnecessarily.

[Tom M King]

I changed all mine to ball valves. I admit to having one that has a nipple held in with JB Weld. It's a really old one mounted up high in the trailer shed. That one gets used so rarely, only for topping off tires, or running an air wrench occasionally that I had just neglected it for too many decades. I decided to change all the others after that one, that was too much trouble to get to with a TIG welder.

[Bruce Page]

Ken, add an automatic drain valve and never mess with it again.
https://sawmillcreek.org/showthread....nally-some-air!

[Charles Lent]

I've gone through 3 automatic drain valves on my 80 gal IR compressor tank and each failed in a very short time, usually only a couple of months. I now just have an accumulator made from two 1/4 - 2" pipe adapters and a 1' long piece of 2" pipe. It's output has a 1/4" ball valve and more pipe to vent it out through the wall of my compressor shed. Whenever I think of it I open the ball valve for a few seconds and the condensate is blown outside. As long as I do this every month or so, no condensate ever builds up in the compressor tank. I just need to remember to only do it when my neighbors aren't outside, because the sudden roar is quite startling.

Charley

[Mike Cutler]

The drain valve on my PC 6 gallon compressor needs replacement and I've never liked the one that came with it. Lowes sells a 1/4 turn ball valve with a 1/4" stem. I'm a bit reluctant to start horsing on the old one because I can't see any threads protruding outside the tank. Is this stem welded or is the paint obscuring any threads?

IMG_1419.jpg

Ken
If it's like mine, that is welded boss on the tank. I put a drain valve in mine also. I no longer use it as a compressor, but as a secondary air receiver tank. The compressor died a few years back.
An auto drain will not work for you on this tank. The drain is above the bottom of the tank, so you won't get the moisture out of the bottom of the tank effectively. I always had to tip mine to put the valve at the lowest point. It's also way too small to realize the benefit of an auto drain.

[Jim Becker]

I've gone through 3 automatic drain valves on my 80 gal IR compressor tank and each failed in a very short time, usually only a couple of months.

I picked up an IR auto drain "for a song" off EBAY years ago and it's not failed yet.

[ChrisA Edwards]

I have to admit, I'd never drained my tank for several years and finally did it prior to getting ready to do some automotive type spraying.

I bled the air out of the tank and then loosened the drain valve. I expected quite a large amount of water to come out, so I moved my compressor to the edge of my garage, but all I got was about 6 drops (little brown stain) of water that didn't even flow out.

Naturally, after loosening the drain, it refused to seal again, so it leaked a little air until I could replace it.

[Charles Lent]

Drain it again when the tank has pressure in it. You will be amazed what comes out. The tank needs some pressure in it to blow the water out. That nasty rusty water from your tank says that the water has been in there a long time and has been heavily rusting the inside of the tank and decreasing it's life. You would be amazed how thin these tanks are, and it doesn't take much rusting to significantly weaken them. It's also amazing how much damage can be caused when one of the little pancake compressor tanks explodes. I can't even imagine an 80 gallon thank exploding. It would flatten the shop and quite likely kill anyone in it.

Charley

https://www.google.com/search?q=phot...obph1RLDqrE4M:

https://www.google.com/search?q=phot...dEVzxBwKWJADM:

[ChrisA Edwards]

Drain it again when the tank has pressure in it.
Charley

Wise words indeed, but realistically, and this is a question, how do you stop this rusting process? Moisture will get in as soon as the compressor runs.

I am going to replace the drain valve with an easier to get to method, as described earlier in this thread.

[Bruce Page]

I've gone through 3 automatic drain valves on my 80 gal IR compressor tank and each failed in a very short time, usually only a couple of months. I now just have an accumulator made from two 1/4 - 2" pipe adapters and a 1' long piece of 2" pipe. It's output has a 1/4" ball valve and more pipe to vent it out through the wall of my compressor shed. Whenever I think of it I open the ball valve for a few seconds and the condensate is blown outside. As long as I do this every month or so, no condensate ever builds up in the compressor tank. I just need to remember to only do it when my neighbors aren't outside, because the sudden roar is quite startling.

Charley

I installed the IR ADV in 3/2005 and it's still functioning as new. I wired an on/off switch and power it up only when I'm using air. I do not leave it powered on 24/7.