How to add refrigerant?

[BioHazard]

As you can tell by my posts here I'm doing a lot of experimenting with air conditioning. I have a 10k BTU window air conditioner that I'm trying to make water cooled. When I'm done, I would need to recharge the A/C with R22. (which I can buy on ebay)

The question is, how can I do that when the window A/C doesn't have any service ports? Do they sell some sort of fitting to add a service port to the copper lines? I might even try propane as a refrigerant, but again, I have the same problem.

[vdubnut62]

Look for a little 1/8th diameter or so stub about 2 or 3 inches long  with the end soldered shut that looks completely out of place.
That's where the charging happens. I don't know how, I call one of my son's friend's Dad.
That confusing enough?
Ron.

[BioHazard]

Look for a little 1/8th diameter or so stub about 2 or 3 inches long  with the end soldered shut that looks completely out of place.

Yep, thought that was for charging. How in the world do you use it? 

[vdubnut62]

I assume there's a little gripper type fitting like for a plastic air line or a pex  water line.
Other than that, no clue.
Ron.

I just had an (for me anyhow) epiphany! Why can't you use a compression fitting and then adapt it to your gauges?

[Tom Reed]

The best thing to do is get a 1/4" schrader valve and put one on the suction and discharge side of the compressor. A schrader valve is like a big tire valve. Then get a set of gauges and hoses so you can see what's going on. If you start to see the suction line freezing up time to loose some refrigerant before the compressor hydrolocks. Put caps on the fittings when not in use.

[Thob]

Search in your favorite industrial supply place for "access valve".  Something like this:

http://www1.mscdirect.com/eCommerce/NavigationServlet/Access-Valves/_/N-77g37?cm_re=Category-_-BodyLink-_-Access+Valves&Ntk=All_MSC&Ntt=a%2Fc+access+valve&Ntx=mode+matchallpartial&Nty=1&rawInput=a%2Fc+access+valve%C2%A2a%2Fc+access+valve

or here:

http://www.grainger.com/Grainger/wwg/search.shtml?op=search&N=11379&in_dim_search=1


or here:

http://www.mcmaster.com/#access-valves/=gfrmqa



Sometimes knowing the right search term is the whole trick.  I had to go dig through the drawer and find a package I bought years ago to figure it out. 

[BioHazard]

Search in your favorite industrial supply place for "access valve".  Something like this:

http://www1.mscdirect.com/eCommerce/NavigationServlet/Access-Valves/_/N-77g37?cm_re=Category-_-BodyLink-_-Access+Valves&Ntk=All_MSC&Ntt=a%2Fc+access+valve&Ntx=mode+matchallpartial&Nty=1&rawInput=a%2Fc+access+valve%C2%A2a%2Fc+access+valve

or here:

http://www.grainger.com/Grainger/wwg/search.shtml?op=search&N=11379&in_dim_search=1


or here:

http://www.mcmaster.com/#access-valves/=gfrmqa



Sometimes knowing the right search term is the whole trick.  I had to go dig through the drawer and find a package I bought years ago to figure it out. 

Fantastic!

[Ronmar]

Dad started a AC and R business when I was in high school.  Used to use a tap assembly that added a pressure test fitting to any coper tube.  The 2 part block clamped over the tube and a sharpened probe punctured the tube and a seal maintained the seal.  This was how he added pressure fittings to a reefer or AC to service it.  Once you get the pressure fittings installed, you need a manifold gauge and a vacume pump to completely evacuate the system of air(and moisture) before you can add new refrigerant.  If the system is open to the air for long, it may need a new drier installed also before recharging.

You might have trouble getting R22 without a lisence, as I think the EPA regs require appropriate training and recovery equipment to work with the stuff.  About the only stuff you can work with over the counter without qualifications is R134, at least untill some government study finds it harms some brazillian bullfrog and that gets restricted as well... 

[BioHazard]

You might have trouble getting R22 without a lisence, as I think the EPA regs require appropriate training and recovery equipment to work with the stuff.

http://www.ebay.com/itm/Refrigerant-R22-15-oz-Can-/170740291901?pt=BI_Commercial_Refrigerators_Freezers&hash=item27c0ea193d

You must be EPA certified to purchase this product and show proof of certification before the item will be shipped.

If the purchase is for "resale only"  to a EPA Certified Technician, you can send us an email indicating the purchase is for "RESALE ONLY TO AN EPA CERTIFIED TECHNICIAN".

[vdubnut62]

I've got an old piston type reefer compressor with a Delco electric motor on it that I use to vacuum automotive systems with,
it'll pull 28". Not too shabby considering it's probably 70 years old.
Ron.

[Thob]

I've used propane for refrigerant before, it worked quite well in one case and only marginally in another.  I guess it depends on whether you want a refrigerant that is flammable, or one that is toxic and corrosive.  The typical old style schrader valve (access valve) used in refrigeration is the same size as a 1/4" copper tube flair fitting.  I cannibalized an old torch, removed the venturi from the top and found a compression fitting that just fit on the main tube, the other end of which I put 1/4" flair fitting.  This created an adapter from the typical 1 pound propane can that my manifold valves would connect to.

I checked one of the online sellers of HC (hydrocarbon) refrigerant, their MSDS indicated that it contains di-methyl methane, which is a synonym for propane.  You can pay $6 a pound for their stuff or buy regular propane just about anywhere for $2 per 1 lb can.

You do need to evacuate the system before adding refrigerant.  R12, R22, and R134a will form corrosive mixtures with any moisture in the system.  Propane doesn't do that, but you still need to get the air and moisture out (moisture will freeze inside the system and plug it up).

[TimSR2]

HC coolant rocks in older systems!  I don't even drain the older coolant now, i just top up with HC.  R12a   Non flammable refrigerants are a  chemical manufacturer's scam, and they always have been.   

The legislator's rules about  'conventional refrigerants" was always that they be non flammable in case of accidental release of gas.  In reality, any accidental release of refrigerant gas is always full of compressor  oil mist, and always an explosive mixture in any case. 

I have 3 cars, All are R22 originally or conversions.   and are all topped up with R12A for 5 years now.   No problems. 

(Engage flame shield..)

[BioHazard]

Ok, somebody back me up here. Tell me straight it's OK to pump propane right out of the green bottle and into an A/C compressor where it gets compressed to around 400 PSI and heated. 

It's not that I don't believe you guys, it's just that sounds really bad. Probably safer than a lot of other things I've done....

Propane is definately far cheaper than R22...I've been refilling the little green bottles for less than a dollar.

[billswan]

Ok, somebody back me up here. Tell me straight it's OK to pump propane right out of the green bottle and into an A/C compressor where it gets compressed to around 400 PSI and heated. 

Well bio I admit to having a central air unit running on propane that came right out of a grill tank that was filled out of a 1000 gallon house tank. It has run for around 20 years that way. And it was a used salvaged unit to boot. Paid $ 40 for it. And yes the unit cools the house I live in.

I also have 2 150 hp farm tractors that use plain old propane also.

By the way check out 134a and see if it will burn? I believe it is listed as nonflammable but try spilling some through a flame and see what happens. Oh by the way if you do that don't breath it in as it is a cancer causer.

Billswan

[Thob]

Ok, somebody back me up here. Tell me straight it's OK to pump propane right out of the green bottle and into an A/C compressor where it gets compressed to around 400 PSI and heated. 

It's not that I don't believe you guys, it's just that sounds really bad. Probably safer than a lot of other things I've done....

Propane is definately far cheaper than R22...I've been refilling the little green bottles for less than a dollar.

Keep in mind that as long as there is not any oxygen in the system, the propane will NOT burn.  No matter how hot or how much pressure.  The propane has to leak out of the system and mix with air to burn (or air has to somehow leak into the system).  There is both an upper and lower flammability limit, I don't know what the numbers are but something like 2% and 10% (propane in air).  Below the lower limit, it's too lean to burn; above the upper limit, it's to rich to burn.  As long as you stay well away from the limits, it shouldn't be a problem.  Getting most of the air out so that when you charge the system with propane should be easy for just about any vacuum pump.