HVAC guys, I pulled a smooth one. Need advice.

[Amianthus]

Well basicly, I boned myself.



It started like this. I checked the operation of my truck's A/C earlier this year and noticed that my pressures were a bit lower than I expected. So I topped it off. Completely forgot to check my temperatures and just set the thing according to lowside pressure (temp). I wound up over-charging it by about 12 ozs. That's stupid manuever number one.



Well, knowing I did this, today I decided to trim the charge and get it back to operating normally. So I hooked up my gauges, connected my 50 lb. tank and started to trim the charge. Well, I went too far. So I added some back in. But wait, my temperatures and pressures were not corresponding to the behavior of R-134a. Low side was sorta right, but the high side was almost 350 psi! I say to myself, "Self, what is going on here?" I look down and realized that I connected my R-22 recovery cylinder instead of my R-134a cylinder! AAARRRRRRRGGGGGHHHHH!!!!!! I've contaminated about 30 pounds of R-22 with R-134a!!!



So I evacuate the system, completely! Then I recharge the system with virgin R-134a and check my temperatures and pressures. It works great. But now I've got all this screwed up refrigerant.



My question is this. I have a recovery unit (obviously) and a filtering unit. Is there any way I can separate these two refrigerants? I know they have different condensing temperatures and pressures. I know this can be done when you have a tank of refrigerant and it has a cap of air, but I don't know about refrigerants. Can I skim the 134a off the top (or bottom)? Or am I just screwed? Let me know what you think.



P. S. - I won't even go into detail on how I screwed up trimming the charge on my new central air unit tonight (works now). It just wasn't my day.

 

[Amianthus]

Oh Well.

I guess by the lack of replies that I am just pretty well screwed.

 

[MidwestMotorman]

not the refrigerant that is the problem

I think the main problem is the oil used with each refrigerant system. The manufacturers have repeatedly said not to mix the systems for oil reasons, but not for actual refrigerant reasons.



The 134 molecules are a lot smaller than the R22, and the 134 would just seep out of an R22 system. I know some people who just pull out the R22 (if there is any left), shake the oil out of the compressor, and put in 134 and just go.



Being 134 molecules are smaller, they should be less dense and sit on top of the mix (in liquid form) as long as 134 evaporates sooner, then the gaseous part will be at the top.



I do not have a masters in chemistry or physics, but am just going by what I remember. The MSDS information should tell you what you need to know about their properties. From that you can get a good course of action.



good luck

 

[DennyDay]

You are screwed!!!!!!!!!!!!!

Sorry to say the mix of R22 and R134a can be tough to get rid of. Most of the re-cycle places won't take it. If you get in the tights contact Honeywell (Old Allied Chemical) in Baton Rouge, LA and they will take it for recycle. You have to ship to them by Motor Freight. Let them toss the container, cost of shipping empty back motor freight more than deposit on cylinder.



Denny

 

[HVAC]

I'm surprised you even need AC up there. How hot could it be in the summer?



Sounds like you might have shot a fifty dollar bill in the hiney. That's how we define a contractor as compared to being an employee, etc. You have the opportunity to loose money

 

[Rob Thomas]

Nowell,



I'm in MI, which is right next to WI, and it's been in the 90's here lately, it gets plenty friggin' hot here. AC is a must for me.



Later, Rob

 

[Amianthus]

Pretty much what I thought.

I pretty much figured that was the case. I can try to separate them, but I think that would be too much trouble and it might not work as well as I thought.

I have a buddy in the airgas business. Maybe he can hook me up somehow.

I don't see the oil thingy being an issue. Polyoilester should be able to mix with the R-22 oil (synthetic I'm pretty sure) without too many problems. But it'll be something I'll have to keep a very close eye on.

Just one more thing. :{