Compressor drain valve - replace with extended ball valve setup

[stickshift]

Compressor old style drain valve - replace with extended ball valve setup

Picked up a used air compressor. It has the old style drain valve where you have to partially unscrew it to drain, which is a real pain, in addition to the usual hassle of reaching to the very bottom of the tank.

I'd like to replace it with a 1/4 turn ball valve and extend it out so that I can operate the valve with my foot.

There's not much ground clearance, and I'd like to not decrease the clearance, since this is a portable compressor and I'll have to move it around and want to minimize risk I shear the fitting off and ruin the tank's threads. I may also add something to pad the steel 'foot' of the compressor (maybe a piece of 1/2" foam board scrap) to reduce vibration back to pump and motor, so that will improve ground clearance a little.

I'm thinking all brass fittings to avoid rust, or does it not matter if I go with galvanized pipe or black pipe?

For the first fitting, I'm thinking either a 1/4" street elbow or a tee fitting, whichever has the lowest profile (again, trying to maximize ground clearance), then a 1/4" ****** that extends out to one side of the steel 'foot' on the handle end of the compressor, then a 1/4" ball valve. I'll zip tie (and eventually ask a friend to weld) the ****** to the steel 'foot', so that operating the ball valve (with my foot) doesn't apply any torque to the elbow at the tank's drain hole.

Thoughts on this plan?

 

[The Cobbler]

your plan makes sense. you can always plumb the valve up higher with flexible copper so you can operate it by hand instead of foot

 

[Bigblockyeti]

I put a 1/4" NPT street elbow on mine, a short ****** and a 1/4 turn ball valve, I don't open it with my foot as you only have to bump it wrong once to have a big mess. If you do break it off, brass will be much easier to extract and less likely to mess up the female threads.

 

[Jswain]

Mount two hockey pucks under the front leg and it will give you some clearance and reduce vibrations a bit.

I like the brass / stainless because as you mentioned it won't rust. The street elbow is a good one as well to save clearance and if you're scared of breaking it off you could go for a higher pressure fitting 3k/5k/7500psi which will give it a thicker wall/harder to break but it's likely not to be a problem

 

[stickshift]

your plan makes sense. you can always plumb the valve up higher with flexible copper so you can operate it by hand instead of foot

I like the idea of the valve higher up so that it can be operated by hand without reaching down to nearly the ground. If the valve is up higher, won't some of the water remain in the line between tank and valve? Or is the idea that massive air pressure will push out all the water in front of it?

 

[Aquamoose]

Re: Compressor old style drain valve - replace with extended ball valve setup

I have the same style compressor. At the end of the day, I simply tip it vertically, reach down to open the valve, and set it back down all while still on my feet.


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[The Cobbler]

The water will blow out of the line with the air pressure

 

[stickshift]

The water will blow out of the line with the air pressure

OK, great. Would be pretty sweet to run the line up along the handle of the compressor, and have the ball valve in easy reach, maybe with an elbow pointed downward to redirect water/air down.

When you say flexible copper, do you mean this?
https://www.homedepot.com/p/Everbilt-1-4-in-x-10-ft-Soft-Copper-Refrigeration-Coil-Tubing-1-4-R-10RE/203654086

How do you make the connection from threaded pipe fittings to this?

 

[The Cobbler]

yes that type of copper, or use nylon plastic tubing . depending on if you're using flared or compression fittings there are fittings available.
a stationary compressor I used for quite a while I used a pc of air hose & a blow gun for draining. grab the blow gun, open the door & shoot away .

 

[BD1]

Re: Compressor old style drain valve - replace with extended ball valve setup

You may consider a 1/4" male pipe thread x 1/4" male pipe thread brass fitting. For Example

https://www.amazon.com/dp/B07795PJWK/?tag=atomicindus08-20

Not sure if male x Female would be shorter tight radius.

https://www.amazon.com/dp/B000BQRHHM/?tag=atomicindus08-20

 

[Zmann]

When I read the title I was expecting a big ole vertical unit

 

[stickshift]

Re: Compressor old style drain valve - replace with extended ball valve setup

You may consider a 1/4" male pipe thread x 1/4" male pipe thread brass fitting. For Example

https://www.amazon.com/dp/B07795PJWK/?tag=atomicindus08-20

Not sure if male x Female would be shorter tight radius.

https://www.amazon.com/dp/B000BQRHHM/?tag=atomicindus08-20

That male x female fitting looks nice and low profile.

 

[stickshift]

yes that type of copper, or use nylon plastic tubing . depending on if you're using flared or compression fittings there are fittings available.
a stationary compressor I used for quite a while I used a pc of air hose & a blow gun for draining. grab the blow gun, open the door & shoot away .

nylon plastic tubing can withstand 120-125 PSI? I'm talking about piping between tank and valve, not downstream of valve.

The HD Husky extended tank drain valve use braided steel flex hose. If cheaper nylon hose would have sufficed, I'd figure they would have used it. Too bad the Husky setup doesn't use a longer hose and a valve with a larger handle, it would have been perfect.

 

[The Cobbler]

I like copper myself, but a lot of compressor unloader valves are plumbed with nylon ( like truck air brake hose)

 

[stickshift]

I like copper myself, but a lot of compressor unloader valves are plumbed with nylon ( like truck air brake hose)

I learn something new every day.

 

[Ing3018]

nylon plastic tubing can withstand 120-125 PSI? I'm talking about piping between tank and valve, not downstream of valve.

Yes, it's fine for this kind of use. I used 3/8 o.d. clear nylon tubing as the drain for mine. Sees constant 175 psi. The small stuff can handle the higher pressures and is good for these non-mainline uses. Flexible copper tubing is fine too.

 

[NUTTSGT]

Got a welder ? You could bend up some steel and weld it to the wheel mounts and back foot. Gaining 1.5" of clearance would make alot of difference and not make it too top heavy.

Looking at the 2nd picture, you may already have room to re-drill the holes for the wheel bolts. Maybe a strip of PT deck board bolted to the back would give you enough clearance ?

 

[stickshift]

Yes, it's fine for this kind of use. I used 3/8 o.d. clear nylon tubing as the drain for mine. Sees constant 175 psi. The small stuff can handle the higher pressures and is good for these non-mainline uses. Flexible copper tubing is fine too.

Good to know. Had no idea this kind of tubing could withstand high pressure.

 

[stickshift]

Got a welder ? You could bend up some steel and weld it to the wheel mounts and back foot. Gaining 1.5" of clearance would make alot of difference and not make it too top heavy.

Looking at the 2nd picture, you may already have room to re-drill the holes for the wheel bolts. Maybe a strip of PT deck board bolted to the back would give you enough clearance ?

No welder, but I could raise up the steel foot using hockey pucks or similar as suggested earlier. PT wood could also work, but I'm also going for vibration absorption.

And you're right, there does seem to be room to drill new holes and drop the wheels a bit lower. But I'll rig up the extended drain valve setup and see how it looks. I can probably raise up the handle end of the compressor when moving it around, such that the fitting at the tank bottom doesn't make contact with anything.

 

[The Cobbler]

but you want to keep the tank pitched forward towards the drain

 

[stickshift]

but you want to keep the tank pitched forward towards the drain

Ah, good point. So if I raise one end up, I need to raise the other end a similar amount to avoid pooling of water.

 

[Ing3018]

Good to know. Had no idea this kind of tubing could withstand high pressure.

Check the pressure rating of the tubing. Mine says 300 psi.

 

[stickshift]

From browsing HD website, here's the sequence of fittings I came up with to be able to run the drain valve up to where the handle is (making it easy to reach the valve from a standing position). As far as I can tell, these are all suitable for high pressure air use. Starting from the tank's female threaded drain:
1/4 in. MIP x 1/4 in. FIP 90-Degree Brass Street Elbow Fitting

1/4 in. OD Compression x 1/4 in. MIP Brass Adapter Fitting

1/4 in. x 10 ft. Soft Copper Refrigeration Coil Tubing

Another 1/4 in. OD Compression x 1/4 in. MIP Brass Adapter Fitting

1/4 in. Lead Free Brass Threaded FIP x FIP Ball Valve

Then to redirect water and air downward, another 1/4 in. OD Compression x 1/4 in. MIP Brass Adapter Fitting and a bit of that flexible copper.

Works out to ~$35 in parts. A little steep, but if it works well, worth it to not have to reach down to nearly the ground to drain water from the tank. Easier it is to drain, the more often I'll do it. But if there's a cheaper way to accomplish the same thing, I'm all ears.

 

[stickshift]

Or how about this more simplified (and cheaper) setup:

same elbow out of the tank as before:
1/4 in. MIP x 1/4 in. FIP 90-Degree Brass Street Elbow Fitting

adapter to step up from 1/4" NPT to 3/8" NPT:
1/4-in x 3/8-in Adapter

then a short air hose, kinda like what @The Cobbler described earlier.
3/8 In. X 3 Ft. Air Hose Lead

finish with ball valve:
Brass 3/8-in FNPT Ball Valve

With the hose zip tied to the handle, I can use some kind of clip to retain the ball valve. When I want to drain, release ball valve from clip, aim at the lawn and blast away.

 

[nadogail]

My compressor drain is a brass street ell, a 4" long ****** and a ball valve that I operate with my toe.

 

[Jswain]

Yeah I'd just go with a street elbow/long enough ****** to get the valve out from underneath the tank and a ball valve. Cheapest and easy to operate with your foot or bite the bullet and bend down once per use, maybe at the same time you're plugging in the power or air line

 

[redmondjp]

One thing to keep in mind here, is that besides being the cheapest for the manufacturer, the other primary advantage of the petcock drain valve is that it holds all of the water inside the tank, where if the water freezes, it will do no damage.

The risk of moving the valve out (and don't get me wrong, I have done this myself a few times) is that the pipe leg between the tank and the valve can fill up with water, which if allowed to freeze can cause a problem. If you are diligent about draining the tank, it shouldn't be an issue. If you aren't, and you have the compressor in a place where it could freeze, you can use heat tape or a small incandescent light bulb on a timer or temperature switch to keep that area warm.

 

[stickshift]

One thing to keep in mind here, is that besides being the cheapest for the manufacturer, the other primary advantage of the petcock drain valve is that it holds all of the water inside the tank, where if the water freezes, it will do no damage.

The risk of moving the valve out (and don't get me wrong, I have done this myself a few times) is that the pipe leg between the tank and the valve can fill up with water, which if allowed to freeze can cause a problem. If you are diligent about draining the tank, it shouldn't be an issue. If you aren't, and you have the compressor in a place where it could freeze, you can use heat tape or a small incandescent light bulb on a timer or temperature switch to keep that area warm.

That's a good point and not one I've seen mentioned before.

It's a portable 20 gal unit, so I will typically be draining it after use, especially in the winter.

 

[stickshift]

I removed the cover to the air filter. It uses pieces of foam as the filter, not the pleated paper circular filter I had on my prior much newer compressor. I guess I can replace with a similar porous foam? Or is there specific air compressor filter foam I should be using?

Pic with foam removed. Is that little pinhole (red arrow) the air intake? Seems rather small for a 20 gal compressor, no?

 

[Jswain]

Is that not two larger holes, one on either side of the small hole?

 

[The Cobbler]

Is that not two larger holes, one on either side of the small hole?

they are the mounting posts fro the filter cover, but yes, there's usually 2 holes in those compressors. I think the small hole is it on this unit and the original filter was a felt type , set in the chanel along the leading edge of the housing there. there are retrofits for a screw in filter, but a bit pricey. I started to make a few but got sidetracked! LOL

 

[stickshift]

Is that not two larger holes, one on either side of the small hole?

Are you referring to those depressions on either side, or the small threaded holes? The latter are the mounting posts for the filter cover.

The former - not sure, there is a very small gap between the edges of those depressions and the material beneath, so it does seem like air could pass through there.

 

[Jswain]

Yeah I seen the mounting posts I meant the larger holes above them in the picture. There wouldn't be much room between the head & the valve plate but I'd guess those are your intake holes

I'd guess the small one mayyy be a crankcase breather if it doesn't have an externally mounted one

Turn it on and see if the two larger ones are sucking and the smaller one blows a little air out of it

 

[stickshift]

Yeah I seen the mounting posts I meant the larger holes above them in the picture. There wouldn't be much room between the head & the valve plate but I'd guess those are your intake holes

I'd guess the small one mayyy be a crankcase breather if it doesn't have an externally mounted one

Turn it on and see if the two larger ones are sucking and the smaller one blows a little air out of it

You were right, those are air ports. The one on the left is pulsing air out (must be with every piston stroke) and the one on the right is sucking air in. Why would air be coming out from the port on the left? Wouldn't the design try to push all the air acted on by the piston into the tank?

Strange too that both are covered by the air filter. Seems you'd only want to cover the air intake. Why slow down air being pushed out?

Didn't notice any obvious flow of air from the tiny hole in the center.

 

[stickshift]

Got the drain valve done. 1/4" NPT elbow to short (maybe 5') 3/8" hose to 1/4"-to-3/8" NPT adapter to 3/8" ball valve. I wanted the larger ball valve as 1/4" ball valve is tiny and 3/8" is a little easier to handle while ensuring my hand isn't in front of the opening when I open it up.

For a portable compressor that's moved around for use, where I'm not going to have a pan always positioned under the drain, I really like the hose drain. I can point it toward grass, bushes, etc., and let 'er rip. Thanks for the idea @The Cobbler.

 

[Jswain]

You may have a leaking Reed valve if air is pulsing out of the intake unless the crankcase breather is somehow tied into them. If your fill times are good I wouldn't worry about it, but if it takes a long time to fill I'd be checking it out. Do you have a model # of the pump or some more pictures all around it

 

[STREETFIGHTER50]

I put a 1/4" NPT street elbow on mine, a short ****** and a 1/4 turn ball valve, I don't open it with my foot as you only have to bump it wrong once to have a big mess. If you do break it off, brass will be much easier to extract and less likely to mess up the female threads.

This exactly

 

[stickshift]

You may have a leaking Reed valve if air is pulsing out of the intake unless the crankcase breather is somehow tied into them. If your fill times are good I wouldn't worry about it, but if it takes a long time to fill I'd be checking it out. Do you have a model # of the pump or some more pictures all around it

I'll take a look for at pump for model # and will post up more pics.

Fill times seems ok on this old (but new to me) 20-gal unit. Longer than the fairly new 10-gal compressor I sold, but doesn't seem to take 2x as long (but my perception of time might be thrown off - that 10-gal comp was painfully loud, while this old belt drive is much quieter so I'm less aware of time passing). I'll have to time it.

 

[Jswain]

https://www.airgastech.com/resources/calculators.html#cfm-calculator

Time it and punch what ya get in there I'm assuming you should be 4-5cfm

 

[The Cobbler]

those are both suction ports. air coming out of one indicates a bad reed valve on that cylinder