Author Topic: Is refrigerant flammable? (getting a compressor from an old air conditioner)  (Read 15330 times)

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Offline Monkeh

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If the olive isn't already a tight fit it won't work. They should only just slip on.
 

Offline XOIIO

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Gave it a try anyways since I was impatient, I'd say possibly half the air was leaking out of it, but it still got my small air cannon to 60 PSI or so, fairly quickly too, and that was with a substantial leak, I'm hoping maybe they have something I can just get the hose into, if so it will work perfectly and I have the female threaded quick connect ready to go!

Offline XOIIO

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Uhg, went to the hardware store to find a solution, spent another $10, got some more olives for each side, and the guy found another brass compression thing, which fit very well over the air hose and inside the olive, and got the gap to less than a millimeter or so I'd say, perfect solution except that while I was tightening it, one of the damn threads broke, apparently the extra brass was too much for it to handle, uhg.

Anyways, plan was to do that and maybe add super glue if it was not perfect, to seal up the little bits where it could leak out, but I had no luck, so I put the hose in the brass insert and dripped a fair bit of superglue in, going to repeat the process and also manually crimp the brass insert around the pipe, then put the thing together with plumbers tape, and hopefully it holds.

It's just so damn hard tog et 1/4" copper pipe to half inch NPT, uhg. If this doesn't work I've wasted a good $20 on this project  |O

Offline NiHaoMike

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R410a is a medium term replacement.  It has already been replaced in Japan by R32 and will be replaced in the rest of Asia, Europe and South America over the next few years.  No idea on North America.  R134a has been replaced by R600a on almost all domestic refrigeration systems and will likely be phased out soon on commercial applications along with R404a.
The irony is that R410a is actually a mix of R32 and R125, the latter of which has a very high GWP and lowers efficiency. I figure the real reason they put that in there is so when the patents expire, they would have a reason to phase it out. They started the phaseout of CFCs and HCFCs when the patents were about to expire, same story with the R134a recently.

My current favorite is R433b as well as other hydrocarbons. They're flammable, but so are all those lithium batteries in common use nowadays. The fluorocarbon industry does whatever they can to discredit "alternatives".
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Offline XOIIO

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Well, didn't work, and I am at the end of my rope, I have no clue how to do this.

I don't suppose the whole inside of the black container for the pump gets pressurized (I hear something rattling around inside) if that were the case I could drill and tap a hole to just put a quick connect on :/

Offline corrado33

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Compression fittings work as a set. The ferrules are matched to the nuts that are matched to the threads on the other side. You can't randomly use whichever size ferrule and whichever size nut you want. It will not work. Compression fittings are also MADE for a certain size tubing. Notice I said tubing not pipe. Pipe is measured on the ID, while tubing is measured on the OD. Compression fittings need a certain OD to work properly. There should be NO gap between the tubing and the ferrule. It should JUST slide on. I often have a bit of trouble putting the ferrules on tubing. Also, compression fittings are not meant to be tightened down as hard as you can. You tighten them by hand, then tighten them 1-2 complete revolutions more, depending on how big of a pipe it is.

Take a look at this. I wouldn't suggest ordering swage in your case because they're expensive, but they're well known for compression fittings. You can also easily find NPT-compression adapters. NOTE: Swagelok compression fittings are NOT compatible with the ones you buy at the store. Period.

http://www.swagelok.com/downloads/webcatalogs/EN/MS-13-151.pdf

The first section after the table of contents is about the dangers of mixing different sized components. If you continue to try to use the wrong products in this application, you're going to hurt yourself.
 

Offline XOIIO

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Uhg, I need to check princess auto's website more often, they have 1/4" compression to 1/4" npt directly, for only a couple bucks. I wasted so much damn money  |O

http://www.princessauto.com/pal/en/Couplers/1-4-in-NPT-Brass-Compression-Fitting/0400044.p

I'm just not sure what pressure these can go up to, I probably won't go much higher than 200 PSI but being able to go to 400 would be nice.
« Last Edit: August 12, 2014, 07:44:02 pm by XOIIO »
 

Offline SeanB

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They normally blow out the tubing before the fitting lets go, and typically they will pop copper tubing at around 400PSI, where the tubing shears off at the olive. Steel tube you might get 600PSI before something fails, and I would not like to be in the area when that happens.

There is a reason airconditioning uses a flared joint in those places where the piping is not hard brazed.
 

Offline Richard Crowley

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400 PSI (or even 200 PSI, for that mater) seems dangerous and potentially lethal with such poor knowledge of the mechanics of high-performance plumbing and fittings.
This is why I asked about the size of the tubing and whether you could actually find suitable fittings for it.
 

Offline XOIIO

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They normally blow out the tubing before the fitting lets go, and typically they will pop copper tubing at around 400PSI, where the tubing shears off at the olive. Steel tube you might get 600PSI before something fails, and I would not like to be in the area when that happens.

There is a reason airconditioning uses a flared joint in those places where the piping is not hard brazed.

Yeah, I would rather braze/solder it but all these fittings are stainless or brass and I don't think you can braze/solder brass/stainless to copper pipe, or if so I don't think my soldering iron cold do it. Pretty sure you need a blowtorch.

Trying to think of a DIY way I could flare the end o the copper tube, but most things would probably do it unevenly. The tools to flare the pipe probably won't be very cheap either
« Last Edit: August 12, 2014, 08:30:57 pm by XOIIO »
 

Offline SeanB

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Flare tools are cheap enough, and very useful if you do work with AC or even just do machinery with hydraulic fittings. Copper pipe brazes quite well to brass, steel or even stainless steel with the right flux and brazing rod. Yes you need a lot more heat than what a soldering iron can give, you can use a MAPP gas torch for small pipes in copper, generally up to 3/4 inch at times, but with larger fittings you really need a hotter flame.
 

Offline XOIIO

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Flare tools are cheap enough, and very useful if you do work with AC or even just do machinery with hydraulic fittings. Copper pipe brazes quite well to brass, steel or even stainless steel with the right flux and brazing rod. Yes you need a lot more heat than what a soldering iron can give, you can use a MAPP gas torch for small pipes in copper, generally up to 3/4 inch at times, but with larger fittings you really need a hotter flame.

Yeah I wouldn't go above 1/2" copper for anything really, if the flare tool is a few bucks for a cheapie I may get it but I can't really justify spending $15 on something I will be using for one thing.

Do those mini jet "soldering irons" work well for small copper pipes and stuff? Used to have a couple though they got clogged, blowing capacitors with those was a lot of fun lol. Lot cheaper than a propane tank one too.

Offline XOIIO

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Well drove across town, princess auto said they had 11, couple hours later they had none. They pointed me to a plumbing store a couple minutes away, and I got the last one, and it cost me 63 cents. Washy can't these store be closer? Raaah

Offline XOIIO

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Okay, what the hell. Someone please explain this to me.

This compressor is 120v
It is orders of magnitude quieter than the one on my 3 gallon air compressor.
It fills the 3 gallon tank in less than a third the amount of time it takes the standard compressor.
It is capable of much higher pressures.

Yes, it's heavier than the entire other compressor, but still.

Why on earth are these not the standard for air compressors? My god it is fantastic compared to the mastercraft one, or any other I have heard running. In the time it normally takes to fill the 7 pound fire extinguisher air cannon to 100PSI with the regular compressor I can fill it to 160PSI twice with this one.

Seriously, this is insane, and even with it just running, no reserve air tank it's not a half bad amount of air to dust off loose particles.

My grandmother picked up a culligan (well not really culligan) water cooler with a small fridge and it has a tiny one of these, I have a feeling it would be amazing in my room for gently dusting off laptop fans and the like, though I am not sure how much air it puts out.

Seriously, this is ludicrous.

I have a 6 gallon air compressor tank (the pancake kind) that I got for a few bucks at the scrap yard, no feet or compressor but it's in good enough shape, I'd like to get feet for it, and mount this on it. I'd need to use some bits of steel and weld them to the old compressor mounts to fit this one on, but it would be so much better. Do that and have a valve to either directly fill the tank (which can do max 150 PSI) or bypass it directly to the hose to fill air cannons and it would be pure awesome, probably would need two separate connectors for the hose, that might be cheaper anyways and not sure if there is a "T" valve or way to do this with only one ball valve but I definitely want to try. This is so much more superior than the mastercrap loud as hell one.
« Last Edit: August 13, 2014, 12:45:39 am by XOIIO »
 

Offline Richard Crowley

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It fills the 3 gallon tank in less than a third the amount of time it takes the standard compressor.
But does that really translate into an equivalent SCFM volume rating?
Are you trying to supply air-driven power tools from this?
The requirements for a refrigeration system aren't quite the same as for supplying a few power tools.
 

Offline XOIIO

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It fills the 3 gallon tank in less than a third the amount of time it takes the standard compressor.
But does that really translate into an equivalent SCFM volume rating?
Are you trying to supply air-driven power tools from this?
The requirements for a refrigeration system aren't quite the same as for supplying a few power tools.

Not powering any air tools, and wouldn't until the air from it stops smelling sweet, but if I have the old compressor on just blowing onto my hand through the hose and little air nozzle it's not as strong as the air conditioning one.

Of course when things get bigger and you want to power three nail guns or something the larger rotary or screw compressors will be better, no doubt, but for these smaller 3 and 6 gallon ones I think that the air conditioning ones can be vastly superior, there is probably a smaller size one that would fill at the same rate of the mastercraft one, and while still being heavy would not be quite so heavy and would be quiet.

Offline ignator

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Your smelling oil from the compressor can that is spraying into your tank. This was mentioned before. The compressor can is at suction pressure. This is so the returning cold refrigerant (Freon is a trade mark name of Dupont) cools the motor windings. This is old enough that it's a reciprocating compressor. Probably a 2 cylinder.
If you have posted any youtube videos of you cutting into this system remove them. You are subject to fines of $25000 for releasing R22. I'm not joking. And your videoing this is evidence to prosecute you.
You did have the right idea of crimping the tubing, then cutting it and brazing the cut closed. This could be done with locking pliers, one on each side of the cut.
If you look there are dead end tubes sticking out of the compressor, or a tee in existing piping that was closed off in the factory, using a special pinch tool.
Understand that a refrigeration compressor is operating in a closed loop, and as such a small amount of oil circulates, as this is used to lubricate the piston rings, and cylinder.
Refrigeration tubing/piping, rigid and soft is measured by outside diameter. Your hardware store uses the 'nominal ID' as this is intended as plumbing for water, and that's how the industry has measured it since it's inception. Note 1/8" and 1/4" plumbing piping is much larger then the nominal ID of it's measurement rating, as the process to manufacture has  improve and allowed the wall thickness to be much thiner (over the last 120 years). The OD of the plumbing had to stay the same for the pipe thread or sweat fitting used.  What is 1/4 OD refrigeration tube, is 1/8" plumbing tube. There is reuse of common piping and fittings, but they are called out differently.

My guess is your compressor will seize someday because you pumped all the oil out. They make a oil separator that collects the find oil mist, and has a float in the bottom that is connected to the suction line of the compressor. This is installed in the hot gas output of the compressor before the condenser in a typical system. Scroll compressors use oil as the 'piston ring' and pump lots of oil during operation.

Also don't ever burn R22 (or other fluorocarbon/halocarbon gases), this creates phosgene gas. This is toxic, and smells sweet. It was used during WW I as a chemical weapon.

Your unit is a HOTPOINT brand which is manufactured by General Electric (Garbage electric IMO). They may have used custom copper tubing throughout as they value engineer the crap out of any of their consumer products, and saving raw copper weight with their volume of manufacture can justify not used COTS (commercial off the shelf). But I don't know specific to this, seems you were having issues with fittings.

I hope this clears up some information that was missing. Sorry about too much information not germane to your post. Working on this was my first schooling back 74-76, and as a lab tech for The Trane Company in La Crosse WI.
 

Offline XOIIO

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Yeah, I wonder how long they last for. Maybe it would be a good idea to occasionally put some oil in the suction side to keep things lubricated? I did just reclaim two nice sized jars of what I believe is silicon oil from a rear projection TV.

Also, I'll edit out that part of the video now, thanks for the advice lol. I do need a good set of locking pliers.

Offline RiverTown

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Why on earth are these not the standard for air compressors?

Because air conditioner and refrigeration compressors aren't designed for long time run.
Another thing is that refrigerant helps with lubrication and cooling.
So while pumping air it can work only for short periods of time, much shorter than standard air compressors.
So you shouldn't use this kind of compressors for powering air tools that require a lot of air (hammers, sandblasters, painting guns, wrenches etc.)
But they are perfect for electronics lab shop air.
You don't need much air in electronics lab and this compressors can be used for dusting, paint brush (for fronts panels etc.), or used as air supplies for desoldering stations and paste dispensers.
Its big advantage is that it is very quiet and can be used even in apartments or offices, without neighbours complaining.
I think that you shouldn't go over 120-150 psi.
It's more than enough for regular use, and I think that you don't have knowledge or confidence in tank and compressor itself to use higher pressures.

I'll try to explain how to properly make air compressor for your lab.
DISCLAIMER: Everything you do, you are doing on your own responsibility.
This tutorial contains working with mains wiring and with high pressure. You should have basic knowledge of electricity and pneumatics.
Any mistakes can lead to the electrical shock or explosion with result of injury or death.
Ebay links are here for example only. I'm not in affiliate with any of the sellers. Items are chosen randomly, and they maybe don't have proper pressure ratings.
Double check that all of items have proper pressure ratings needed for your sistem before you buy them. Buy locally if you can and check all details prior buying, ask seller anything that isn't clear for you.


You already have compressor and tank, and they are expensive parts of project.
First of all you will need some kind of filter on the compressor inlet so that dust can't get in.
You can use gasoline filter used on motorcycles and lawn mowers.
http://www.ebay.com/itm/3-INDUSTRIAL-HIGH-PERFORMANCE-UNIVERSAL-INLINE-GAS-FUEL-FILTER-5-16-4-L-NEW-/171399419009?pt=Motors_Car_Truck_Parts_Accessories&hash=item27e8339481&vxp=mtr
Now we have solved the inlet.

Another thing that we will need is pressure switch. Something like this, they aren't expensive:
http://www.ebay.com/itm/Heavy-Duty-Air-Compressor-Pressure-Switch-Control-Valve-90-PSI-120-PSI-F1-/321453020305?pt=LH_DefaultDomain_0&hash=item4ad817d491

Safety valve with proper pressure rating is a M U S T..
http://www.ebay.com/itm/1-4-BSPT-Air-Compressor-Pressure-Relief-Valve-Safety-Release-Valves-/360614076885?pt=LH_DefaultDomain_0&hash=item53f64621d5
http://www.ebay.com/itm/New-1-4-safety-relief-valve-for-air-compressor-150-psi-/190692710351?pt=LH_DefaultDomain_0&hash=item2c662bd7cf

You should have manometer gauge to control pressure in the tank.

Check valve is highly recommended, it allows easy start for compressor (it will be unloaded).
There are different types of check valves, here is one example.
http://www.ebay.com/sch/i.html?_odkw=check+valve&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR12.TRC2.A0.H0.Xcheck+valve+air+compressor&_nkw=check+valve+air+compressor&_sacat=0

Now we covered all things related to the pressure switch.
As you already know compressor is full of oil, and small amount will be sprayed with the air.
We must prevent this for two reasons. First oil must stay in compressor, or it will die. Another reason is that you don't want any oil in your air tools or on the electronics you want clean of dust.
We will use oil/water separator for that purpose.
http://www.ebay.com/itm/TEKTON-4755-Oil-Water-Separator-/221477545760?pt=LH_DefaultDomain_0&hash=item3391172720
You must be sure to use separator that have right pressure ratings.
These separators have small valve, so you can return any trapped oil back to the compressor through air inlet (of course you need to remove filter first).

On the output you should have air regulator. They are cheap and come with air pressure gauge and additional separator.
Additional separator is also highly recommended because there will be some condensed water in the tank.
http://www.ebay.com/itm/1-4-Air-Filter-Regulator-Lubricator-Combination-Water-Oil-Separator-AFC-2000-GBW-/151231391994?pt=LH_DefaultDomain_0&hash=item233617e8fa

You should put quick air hose couplers after regulator for easy connecting.

This is how you should connect everything.
First you should instal filter on the air inlet.
First thing that goes to the air outlet is w/o separator, then check valve. From there you go to the tank.
If there isn't any convenient place to install safety valve and manometer on the tank you can install them after check valve.
First thing that you should install on the output of the tank is pressure switch. I won't explain how to wire it, or how to adjust pressures. Check your switch manual for that.
Air regulator goes after pressure switch, and then quick coupler is mounted.
Some air tanks have valve at the bottom. It's recommended to open that valve and let condensed water to drain out once a year.
 

Offline SeanB

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Refrigerant oil is not something to just chuck any oil in. Luckily for you this unit is old enough that the oil is straight SAE10 mineral oil, so the replacement oil must be a plain mineral oil, not a silicone oil, which will turn into gum and grinding paste inside the unit. Rear projection TV sets use a silicone based oil that is designed to be optically clear, it is not a lubricant at all.

You can go to any tool supplier and get air oil, designed for putting into air powered equipment, quite cheap. It is mostly clear and thin, and is ideal for this compressor, though you can also go and buy proper mineral refrigeration oil, I buy Fuchs Reniso 32 compressor oil in gallon bottles for use in vacuum pumps, as it is a good lubricant and the right viscosity. It also is a good general purpose light oil that does not go tacky.

Other refrigerant oils are based on organic acids and will turn into something that eats metal and corrodes copper when exposed to air and water. They are not something you want to use in any application other than a closed hermetic system.
 

Offline XOIIO

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Alright, so a way to identify the oil type is that sweet smell then?


Good tips, wouldn't have thought to put a filter on the input end, already have a quick connect mounted directly to it, and a couple local stores sell water/dirt filters for the output side, I'll get one of those whenever I start using this on stuff other than my air cannon, I also need one for the 33 gallon well pressurization tank I got for use as an air cannon/reserve air supply (just reserve air for now).

The little 6 gallon pancake tank I have already has the valve at the bottom, unfortunately the regulator that came with it was smashed to shit. I think when I get my angle grinder/auto darkening helmet I will take the paint off the four old compressor mounts, weld some steel plates to those, and drill holes to mount the compressor on top. Might even be able to re-use some of the galvanized stuff from the air conditioner though I'll be sure to do it with more ventilation.

Offline NiHaoMike

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For your use, you can just put car engine oil in the compressor.
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Offline XOIIO

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Ohboy  >:D

The light is pretty low today, but I managed to get one reading on my chrono, at 200PSI, my mini air cannon shot a rock at 345FPS, and it can go up to 250 no problem, that's where y current gauge maxes out, but when I tried it the barrel blew off too lol, I need to get some hearing protection though, it's quite a snap when you fire it.

Offline kc9qvl

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Take a picture of label on the compressor most will say what is in it. "min" mineral oil, "a/b alkylbenzene, "poe" polyolester.

most likely mineral oil, possibly alkylbenzene, too old to be polyolester.
 


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