Funny thing is I am a retired SAT Diver Well versed in mixed gas at various depths. Henrys Law deals with pressure, temp and partial pressures. But I was on the breathing end of things and did not mix my own gas. And certainly never messed with 134A. Lots going on now with florocarbons. They are a light liquid infused with O2. Since it is a liquid all other gasses can be eliminated. Dive deeper stay longer etc. Cept its a bitch breathing a liquid. Rats can do it but they dont fare well for long. Back to AC My orignal reply to the post was I did not think you could over fill a system unless you pumped it in under additional pressure. All gasses given the chance will equalize.

 

ok so my question still remains.... what should i do now? add more or what?

 

keep in mind the refiderant cans ARE under pressure so it is forcing its self into the line, but i doubt it is at a higer pressure than the system... and yes pressures will equalize but i dont know if the systems know whats too high a pressire to relieve its self...

 

As I said above the refrigerant is sucked in on the low side with the engine running and yes the can is at a higher pressure than the low side. There is a restriction between the low and high side at the entrance to the evaporator to divide the two sides.

With the engine not running both sides will equalize to about 90 PSI on a charged system. A lot depends on the OAT when you check the system and you have to get a feel for what the pressure will be under a given condition.

If you are cycling off the low-pressure switch on a hot day (OAT 90*+ F) then yes you are low and need another can but you may not need the whole can. But you would not need another can if it is a cold day (OAT 0* F) and cycling off the low-pressure switch.

 

Honestly if you have no idea what you are doing, it would be better to just have it done by a HONEST technician(hard to find)!! Recharging your a/c can cause more problems if you don't know what you are doing, especially if you are converting to another refrigerant. Not only that but you could hurt yourself. I am not sure if I am right about this in vehicles Subford, but mixed refrigerant causes a difference in pressure in the system and could cause faults within the system when mixed...pressure/ temp, right?

 

Yes you are right, you never want to mix them.

 

I thought so!

 

I'm not an idiot, i had the 134a in the truck anyways. ford started using that mix in 1994 (on the f150 anyways), also CFC free. If I'm not mistaken, you can;t buy the older refrigerants anymore for they are toxic to the environment. I've talked to a Ford technician i know and he told me the system holds three cans, and where my compressor actually stopped as if it was seized, I'm banking on it was bone dry.

Now I'm not trying to call myself an expert, cause I'm no where close to that, but i do research vehicles, mainly Ford 92-96, and i know a thing or two.

Thanks for the great help! Any more suggestions for me?

 

I know your not an idiot, and I wasn't asking in lew of anyone being an idiot, just for my own knowledge because I wasn't sure if that still applied with vehicles as it does with commercial freon. I figured it did though. Never hurts to ask they way people throw things together now adays. Ready to help you out anytime NeXtras.

 

what i sed wasnt directed at you completely lol... just stating for the general audience.

You think i should try to add in another can and see how it acts? or what?

 

Well then I guess you were talking about me and I was never trying to say you were an idiot just trying to answer your questions the best I could.

As far as the guy telling you it held three cans, he would not know that any more than I would unless he read the sticker under the hood of your truck.

If your system was completely empty then you would have air in it and without vacuuming it out it will never work right not to mention the moisture in it.

I think you misunderstood the term “mixing them”.
What I think Motorhead26 was asking was having some R12 in a system and adding some R22 or Freeze 12 to the system would that be OK. It would not.
When you have two or more Refrigerants mixed together there is no way to tell what the pressure temperature relationship is and also if you then reclaim the charge you have problems when you take it to the EPA recycling center.
I know that 134a is a mix and so is Freeze 12, and others, but you do not want to mix them with other gases.

No one can tell you if it needs another can without looking at the gauges and knowing what contaminants are in it, but if it is shutting down on the low side on a hot day it more than likely needs more in it.

 

Could be a shortage, but like Subford said get some guages and check it. Saving money and doing things yourself when it comes down to a/c systems may sound like a alright job, but without the equipment and knowledge to do so you are looking at $$$ down the road, that you could have saved for all those gas prices today! Over time you will have problems if its not done right. Talk to some auto guys in your area who are EPA and get some feedback. Typically they will tell you what is best for your type of system. Not blowing you off, but I always like one on one with whoever is working on my things. You can always throw it our way and get some advice on whats best.

The recycling center will not accept or give out freon unless you are certified to handle refrigerants. That is how the auto garage can charge you so much because they do the foot work and charge you to put in the same refrigerant they just took out of your system. Seen it done, and its not cheap. I would make sure your recovery process is SAT before recharge. Just be safe man!

 

so... i added another can of refridgerant and the compressor seems to be staying on for a good amound of time... more than a minute it holds three cans so i think im good for no... condensor and the A/C line was VERY cold and the high side was pretty hot so thats good